Uses and compositions

Abstract

A use of a polymer to treat a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water rep

Description

Various compounds and compositions are known to impart various properties to substrates, especially the surfaces of substrates, with which they are contacted. Some materials have surfaces (such as rough and / or water absorbent surfaces) that readily accumulate dust and / or dirt and are difficult to clean. This can cause problems such as reducing the cleanliness, robustness, and / or longevity of the material, as well as making the material aesthetically unappealing. It can be desirable to apply suitable compounds and compositions to such materials to provide benefits such as increased water repellency, reduced friction, and improved visual appearance (such as improved visual appearance). Silicone compounds, such as polydimethylsiloxane, functionalised polydimethylsiloxanes, organosilicones, and related compounds are widely used to impart water repelling, low-friction and shine properties to surfaces, including imparting lubrication and / or softening properties. However, there are a number of disadvantages associated with the use of such silicone compounds, including their low biodegradability, which has led to environmental concerns. It is thus an object of the invention to provide an alternative to silicone compounds that can be used in a wide range of applications to provide impart water repelling, low-friction and shine properties to surfaces, including imparting lubrication and / or softening properties. It is another object of the invention to provide alternatives to silicone compounds that are more biodegradable whilst having equal or improved water repelling, low-friction and shine properties to surfaces, including imparting lubrication and / or softening properties. Summary of the Invention According to aspects of the present invention, there is provided a use, method, composition and substrate as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and from the description which follows. The inventors have identified that certain polymers can provide at least one of increased water repellency, reduced friction, and improved visual appearance to surfaces, which is at least comparable to that provided by known silicone compounds, whilst also being more biodegradable. According to a first aspect of the invention, there is provided a use of a polymer to treat a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance; and wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. According to a second aspect of the invention, there is provided a method of treating a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, the method comprising contacting the surface with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. According to a third aspect of the invention, there is provided a composition for treating a surface that is not a surface of a home care substrate, wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, and wherein the composition comprises one or more polymers, wherein the or each polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. According to a fourth aspect of the invention, there is a provided a substrate that is not a home care substrate, wherein a surface of the substrate is treated with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. Other features of the invention will be apparent from the dependent claims, and from the description which follows. Features described in relation to the third and fourth aspects may have any of the suitable features and advantages described in relation to the first and second aspects. Detailed Description of the Invention Unless otherwise stated, the following terms used in the specification and claims have the meanings set out below. The terms “alkyl” and “alkylene” include both straight and branched chain alkyl and alkylene groups respectively unless otherwise stated. References to individual alkyl groups such as “propyl” are specific for the straight chain version only and references to individual branched chain alkyl groups such as “isopropyl” are specific for the branched chain version only. For example, “C3-30 alkyl” includes C6-24 alkyl, Ce-s alkyl, propyl, isopropyl and t-butyl. The term “alkenyl” includes both straight and branched chain alkenyl groups. References to individual alkenyl groups such as “propenyl” are specific for the straight chain version only and references to individual branched chain alkenyl groups such as “isopropenyl” are specific for the branched chain version only. For example, “C3-30 alkenyl” includes C6-24 alkenyl, Ce-s alkenyl, propenyl and isopropenyl. Herein C3-30 means a group having from 3 to 30 carbons atoms therein, for example having 3, 4, 5 etc up to 30 carbon atoms. The term "hydrocarbyl" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. As used in the specification and the appended claims, the singular forms "a", "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of’ means including the components specified but excluding other components except for components added for a purpose other than achieving the technical effect of the invention. The term “consisting of’ or “consists of’ means including the components specified but excluding other components. Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to include the meaning “consists essentially of’ or “consisting essentially of’, and also may also be taken to include the meaning “consists of’ or “consisting of’. As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts of percentages may be read as if prefaced by the word “about”, even if the term does not expressly appear. The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1,2,3,4 when referring to, for example, a number of elements, and can also include 1.5,2,2.70 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein. The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each exemplary aspect of the invention, as set out herein are also applicable to any other aspects or exemplary aspects of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each aspect or embodiment of the invention as interchangeable and combinable between different aspects of the invention. As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination. The term “monomer” is used herein to refer to a compound comprising at least one polymerisable functional group. As reported herein, the number average molecular weight was determined by gel permeation chromatography using a polystyrene standard according to ASTM D6579-11 (“Standard Practice for Molecular Weight Averages and Molecular Weight Distribution of Hydrocarbon, Rosin and Terpene Resins by Size Exclusion Chromatography”. UV detector; 254 nm, solvent: unstabilised THF, retention time marker: toluene, sample concentration: 2mg / ml). According to a first aspect of the invention, there is provided a use of a polymer to treat a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance; and wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. According to a second aspect of the invention, there is provided a method of treating a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, the method comprising contacting the surface with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. Suitable features of the first and second aspects will now be described. The polymer as used herein is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers as defined herein. In other words, the polymer may be obtainable or obtained by polymerising monomers comprising one or more first monomers and optionally one or more second monomers as defined herein. Thus, the reaction product is a polymer comprising repeat units derived from the one or more first monomers and optionally repeat units derived from the one or more second monomers as defined herein. When the polymer is the reaction product of monomers comprising one or more first monomers only (and no second monomers), the polymer may be a copolymer (i.e. made from two or more first monomers) or a homopolymer (i.e. made from only one first monomer). Preferably when the polymer is the reaction product of monomers comprising one or more first monomers only (and no second monomers), the polymer is a copolymer (i.e. made from two or more first monomers). It is preferred that the polymer is a copolymer. For example, it is preferred that the polymer is a copolymer comprising two or more first monomers (i.e. wherein the two or more first monomers are different) or is a copolymer comprising one or more first monomers and one or more second monomers, wherein the first and second monomer are as defined herein. Preferably, the polymer is not a homopolymer made from ricinoleic acid as the (single) first monomer, i.e. preferably the polymer is not polyricinoleic acid. Preferably, the polymer is not a homopolymer made from hydroxystearic acid as the (single) first monomer, i.e. preferably the polymer is not polyhydroxystearic acid. When the polymer is the reaction product of monomers comprising one or more first monomers and one or more second monomers, the polymer is a copolymer. The copolymer may be made from one or more first monomers and one or more second monomers. The polymer as used herein may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers as defined herein. In other words, the polymer may be obtainable or obtained by polymerising monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers as defined herein. Thus, the reaction product may be a polymer consisting essentially of or consisting of repeat units derived from the one or more first monomers and optionally the one or more second monomers as defined herein. Typically, the polymer that is the reaction product of the monomers defined herein is a polyester. The first and second monomers may be reacted in any suitable molar ratio to make the polymer, as would be appreciated by a person skilled in the art. Thus repeat units in the polymer derived from the first and second monomers may be present in the polymer in any suitable molar ratio and in any suitable arrangement. The first and second monomers may be reacted in a molar ratio of from 1:10 to 10:1, preferably from 1:6 to 6:1, for example from 1:3 to 3:1. Ratios refer to the total amounts of first monomers or second monomers if more than one first monomer or second monomer is present. The polymer may be prepared by any suitable method, as would be known to persons skilled in the art. Suitably, the polymer is not in a solid form. For example, the polymer is preferably in the form of a liquid or gel, preferably a liquid. Suitably, the polymer herein that is the reaction product of monomers comprising one or more first monomers and one or more second monomers is substantially free or free of cross-linking. In some embodiments, the polymer does not contain any nitrogen atoms. References herein to a reaction product of monomers comprising the first and second monomers are intended to refer to a product of the reaction of monomers comprising the first and second monomers conducted in any suitable manner. For example, the reaction may occur between the first and second monomers in the absence of other monomer(s) or may occur in the presence of other monomer(s). The or each of the one or more first monomers used to make the polymer is a hydroxycarboxylic acid or a cyclic ester thereof. Mixtures of two or more different first monomers (i.e. different hydroxycarboxylic acid or a cyclic ester thereof) may be used to make the polymer. Any suitable hydroxycarboxylic acid or a cyclic ester thereof may be used to make the polymer, as would be understood by the person skilled in the art. The first monomer may be a hydroxycarboxylic acid or a cyclic ester thereof. The first monomer may preferably be a hydroxycarboxylic acid. The hydroxycarboxylic acid suitably comprises one or more hydroxy groups and one or more carboxylic acid groups. The hydroxycarboxylic acid may be a monocarboxylic acid comprising one or more hydroxy groups. The hydroxycarboxylic acid may be of the formula R(CR2)nCOOH, wherein n is from 1 to 30 and each R is independently hydrogen, a hydroxy group, or a substituent other than a hydroxy group, and when n is 2 or more, two R groups on adjacent carbon atoms may optionally be taken together to form a double bond, wherein at least one of the R groups is a hydroxy group. n is suitably from 1 to 25, preferably from 1 to 20, more preferably from 1 to 17. Each (CR2) group can be the same or different. Unless otherwise specified, the terms “each R”, “R groups” and the like are intended to refer to all instances of the “R” group in the formula R(CR2)nCOOH, including the R groups in the (CR2)n group and the terminal R group outside of the (CR2)n group. In addition to at least one of the R groups being a hydroxy group, at least one of the R groups may be a substituent other than a hydroxy group. Any suitable substituent may be used. The substituent may be a hydrocarbyl group or a heteroatom-containing group. By the term “heteroatom” we mean an atom other than carbon or hydrogen, such as oxygen or nitrogen. Examples of suitable substituents include amino groups, carboxyl groups, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups, wherein the alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups are optionally substituted with one or more of a hydroxy group, an amino group, and / or a carboxyl group. Suitably, one or two (preferably one) R groups are a hydroxy group and the remaining R groups are each independently hydrogen or a substituent other than a hydroxy group. One or two (preferably one) R groups may be a hydroxy group and each of the remaining R groups may be hydrogen. The hydroxycarboxylic acid may be selected from glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), or dihydroxystearic acid. Alternatively, one or two (preferably one) R groups may be a hydroxy group, at least one of the R groups may be a substituent other than a hydroxy group, and the remaining R groups may be hydrogen. For example, one or two of the R groups may be a substituent other than a hydroxy group. One or two (preferably one) of the R groups may be a hydroxy group, one or two of the R groups may each independently be an alkyl group, a hydroxy-substituted alkyl group, or an aryl group, and the remaining R groups may be hydrogen. The hydroxycarboxylic acid may be 2,2-bis(hydroxymethyl)propionic acid or mandelic acid. When n is 2 or more, two R groups on adjacent carbon atoms may be taken together to form a double bond. The hydroxycarboxylic acid may comprise one or more such double bonds. The double bond may be in a cis or trans configuration. At least one R (preferably one) may be a hydroxy group, two R groups on adjacent carbon atoms may be taken together to form a double bond and the remaining R groups may be hydrogen. The hydroxycarboxylic acid may be ricinoleic acid. The hydroxycarboxylic acid may comprise two or more carboxylic acid groups. The hydroxycarboxylic acid may be of the formula HOOC(CR’2)nCOOH, wherein n is from 1 to 30 and each R’ is independently hydrogen, a hydroxy group, or a substituent other than a hydroxy group, wherein at least one of the R’ groups is a hydroxy group. Suitable features of the hydroxycarboxylic acid of the formula HOOC(CR’2)nCOOH will now be described. n is suitably from 1 to 20, preferably from 2 to 16, more preferably from 2 to 12, for example from 2 to 10. Each (CR’2) group can be the same or different. Unless otherwise specified, the terms “each R’”, “R’ groups” and the like are intended to refer to all instances of the “R”’ group in the formula HOOC(CR’2)nCOOH. In addition to at least one of the R’ groups being a hydroxy group, at least one of the R’ groups may be a substituent other than a hydroxy group. Any suitable substituent may be used. The substituent may be a hydrocarbyl group or a heteroatom-containing group. Examples of suitable substituents include amino groups, carboxyl groups, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups, wherein the alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups are optionally substituted with one or more of a hydroxy group, an amino group, and / or a carboxyl group. Suitably, one or two R’ groups are a hydroxy group and the remaining R’ groups are each independently hydrogen or a substituent other than a hydroxy group. One or two R’ groups may be a hydroxy group and each of the remaining R’ groups may be hydrogen. Alternatively, one or two R’ groups may be a hydroxy group, one or two of the R’ groups may be a substituent other than a hydroxy group, and the remaining R’ groups may be hydrogen. One or two of the R’ groups may be a hydroxy group, one of the R’ groups may optionally be a carboxyl group or a carboxyl-substituted methyl group, and the remaining R’ groups may be hydrogen. The hydroxycarboxylic acid may be malic acid, tartaric acid, or citric acid. The or each hydroxycarboxylic acid may be hydroxystearic acid (preferably 12-hydroxystearic acid) or ricinoleic acid. Preferably, the hydroxycarboxylic acid may be ricinoleic acid. The first monomer may be a cyclic ester of a hydroxycarboxylic acid. The hydroxycarboxylic acid may suitably be as described above. By the term “cyclic ester” of a hydroxycarboxylic acid we mean a compound comprising a cyclic group, wherein the cyclic group comprises one or more ester groups. The ester may be a cyclic monoester or a cyclic diester. The cyclic ester may correspond to a single cyclised molecule of the hydroxycarboxylic acid. This may, for example, be formed by an intramolecular reaction between the hydroxy group and the carboxylic acid group on one molecule of the hydroxycarboxylic acid. Alternatively, the cyclic ester may correspond to a cyclic dimer of a hydroxycarboxylic acid. This may, for example, be formed by an intermolecular reaction between the hydroxy groups and the carboxylic acid groups on two molecules of the hydroxycarboxylic acid. The first monomer may be a cyclic ester of formula (I) or (II): wherein R1 is hydrogen or a hydrocarbyl group; each R2 is independently hydrogen or a hydrocarbyl group; n2 is from 1 to 29; each R3 is independently hydrogen or a hydrocarbyl group; n3 is from 1 to 29; each R4 is independently hydrogen or a hydrocarbyl group; and n4 is from 1 to 29. R1 may be a hydrocarbyl group. The hydrocarbyl group suitably contains from 1 to 12 carbon atoms, such as from 1 to 6 carbon atoms. The hydrocarbyl group may be an alkyl, alkenyl, aryl, aralkyl, or alkaryl group. R1 may be an alkyl group. The alkyl group suitably contains from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. R1 may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, ort-butyl. R1 is preferably hydrogen. Each R2 is independently hydrogen or a hydrocarbyl group. The hydrocarbyl group suitably contains from 1 to 12 carbon atoms, such as from 1 to 6 carbon atoms. The hydrocarbyl group may be an alkyl, alkenyl, aryl, aralkyl, or alkaryl group. Each R2 may independently be hydrogen or an alkyl group. The alkyl group suitably contains from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. R2 may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, ort-butyl. Each R2 may be hydrogen. Alternatively, at least one R2 may be a hydrocarbyl group, preferably an alkyl group, and any remaining R2 groups may be hydrogen. n2 is suitably from 1 to 20, preferably from 1 to 10, such as from 2 to 5. Preferably, n2 is 3 or 4. Each R3 is independently hydrogen or a hydrocarbyl group. The hydrocarbyl group suitably contains from 1 to 12 carbon atoms, such as from 1 to 6 carbon atoms. The hydrocarbyl group may be an alkyl, alkenyl, aryl, aralkyl, or alkaryl group. Each R3 may independently be hydrogen or an alkyl group. The alkyl group suitably contains from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. R3 may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, ort-butyl. Preferably at least one R3 is a hydrocarbyl group, such as methyl. n3 is from 1 to 20, preferably from 1 to 10, such as 1 or 2. Preferably, n3 is 1. Each R4 is independently hydrogen or a hydrocarbyl group. The hydrocarbyl group suitably contains from 1 to 12 carbon atoms, such as from 1 to 6 carbon atoms. The hydrocarbyl group may be an alkyl, alkenyl, aryl, aralkyl, or alkaryl group. Each R4 may independently be hydrogen or an alkyl group. The alkyl group suitably contains from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. R4 may be selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, ort-butyl. Preferably at least one R4 is a hydrocarbyl group, such as methyl. n4 is from 1 to 20, preferably from 1 to 10, such as 1 or 2. Preferably, n4 is 1. Preferably, -(CHR3)n2- and -(CHR4)n3- in formula (II) are the same. Suitably, the first monomer may be a cyclic ester of formula (I) or (II) wherein: R1 is hydrogen; each R2 is independently hydrogen or an alkyl group; n2 is from 2 to 5; each R3 is independently hydrogen or a hydrocarbyl group wherein at least one R3 is a hydrocarbyl group; n3 is 1 or 2; each R4 is independently hydrogen or a hydrocarbyl group wherein at least one R4 is a hydrocarbyl group; and n4 is 1 or 2. The cyclic ester may be a lactone. Examples of suitable lactones include y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, and DL-lactide. Preferably, the lactone is s-caprolactone, menthide, or DL-lactide. Suitably, the or each hydroxycarboxylic acid or the cyclic ester thereof may be selected from glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, or DL-lactide. Preferably, the or each hydroxycarboxylic acid or the cyclic ester thereof may be selected from glycolic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, s-caprolactone, menthide, or DL-lactide (especially glycolic acid, ricinoleic acid and citric acid; most preferably glycolic acid and ricinoleic acid). In some embodiments, mixtures of two or more different first monomers may be used to make the polymer. For example, the one or more first monomers may comprise a mixture of DL-lactide and citric acid or s-caprolactone. Alternatively, the one or more first monomers may comprise a mixture of ricinoleic acid and a further hydroxycarboxylic acid selected from glycolic acid, mandelic acid, malic acid, or citric acid. Preferably, the or each first monomer is a hydroxycarboxylic acid as disclosed herein (and not a cyclic ester thereof). The hydroxycarboxylic acid or a cyclic ester thereof compounds discussed herein may be commercially available or may be prepared using procedures well known in the art. Optionally, one or more second monomers may be used to make the polymer. Preferably, the polymer is the reaction product of monomers comprising one or more first monomers as defined herein and one or more second monomers as defined herein. References herein to the second monomers are intended to refer to the polymer when one or more second monomers are used to make the polymer. The or each of the one or more second monomers (when present) used to make the polymer is one or more of the following: (i) cyclic anhydride; (ii) polyol; (iii) polycarboxylic acid or reactive equivalent thereof; (iv) monocarboxylic acid or ester thereof; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. Preferably, the or each of the one or more second monomers (when present) used to make the polymer may be one or more of the following: (i) polyol; and (ii) polycarboxylic acid or reactive equivalent thereof. Mixtures of two or more different second monomers may be used to make the polymer. For example, two or more of any of the monomers (i) to (viii) as defined herein may be used, and / or two or more of each of the monomers (ii), (ii) etc may be used. Any suitable monomer (i) to (viii) as defined herein may be used to make the polymer, as would be understood by the person skilled in the art. The one or more second monomers (when present) are different to the one or more first monomers. Thus, any monomer that represents a hydroxycarboxylic acid or a cyclic ester thereof is considered herein to be a first monomer, and not a second monomer. For example, when ricinoleic acid and glycolic acid are used to make the polymer, they are both considered to belong to the group of first monomers and not to the group of second monomers, such as monoalcohols or monocarboxylic acids or esters thereof. In other words, the one or more second monomers are not hydroxycarboxylic acids or cyclic esters thereof. One or more of the second monomers may be a cyclic anhydride. By the term cyclic anhydride we mean a compound (or monomer) that comprises at least one anhydride group that is contained within a ring structure. For example, the ring structure that contains the anhydride group may comprise from 4 to 8 atoms, which atoms are typically carbon and oxygen. The ring structure that contains the anhydride group may be saturated or partially unsaturated (and is preferably saturated). The cyclic anhydride compound may typically comprise more than 8 atoms. For example, suitable cyclic anhydrides may include one or more of an anhydride of formula (III), of formula (IV) and of formula (V): wherein in formula (III) R5 and R6 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; in formula (IV) R7 and R8 are each independently selected from hydrogen, an alkyl group and an alkenyl group, or R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; and in formula (V) X is CR13R14, O, S, or NR15; R9, R10, R11, R12, R13, R14, and R15 are each independently selected from hydrogen, an alkyl group and an alkenyl group, and / or any of R9, R10, R11, R12, R13, R14, and R15 together with the atoms to which they are attached represent an optionally substituted cyclic group. Cyclic anhydrides of formula (III) are preferred. X may suitably be CR13R14, O, or S. Preferably, X is CR13R14. When any of R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, and R15 represents an alkyl group or an alkenyl group, the or each alkyl or alkenyl group may be branched or unbranched. The or each alkyl group may contain from 1 to 30 carbon atoms and the or each alkenyl group may contain from 2 to 30 carbon atoms. Preferably, each alkyl or alkenyl group may contain 6 or more carbon atoms. For example, the or each alkyl or alkenyl group may contain from 6 to 30, such as from 8 to 24, carbon atoms (i.e. may be a Ce-30, such as a Ca-24, alkyl or alkenyl group). When any of R5 and R6, or R7 and R8, orR9, R10, R11, R12, R13, and R14 represents an alkenyl group, the alkenyl group may be a polyisobutenyl group. The polyisobutenyl group (when present) suitably has a number average molecular weight of from 100 to 2000, preferably from 100 to 1000, for example 260 or 550. The cyclic anhydride may be a polyisobutenyl succinic anhydride, for example wherein the polyisobutenyl group has a number average molecular weight of 260 or 550. When any of R5 and R6, or R7 and R8, orR9, R10, R11, R12, R13, and R14 represents an alkenyl group, the alkenyl group may be derived from a terminal olefin or an internal olefin. For example, the cyclic anhydride monomer may be an alkenyl substituted succinic anhydride prepared by the reaction of an alkene with maleic anhydride, wherein the alkene is a terminal olefin or an internal olefin. In some embodiments the alkenyl group may be derived from a terminal olefin. The term terminal olefin is used to refer to alkene compounds having a predominantly terminal double bond. Such compounds are also commonly described as terminal alkenes. Terminal double bonds terminate in a =CH2 group and may either be at the a-position or may be vinylidene groups. The terminal olefin is preferably an a-olefin. Examples of suitable terminal olefins include C12 terminal olefin, C15-18 terminal olefin, Cieterminal olefin and C18 terminal olefin. In some preferred embodiments the alkenyl group is derived from an internal olefin. The term internal olefin is used to refer to alkene compounds in which the alkene groups are predominantly not terminal. Examples of suitable internal olefins include C12 internal olefin, C15-18 internal olefin, C16 internal olefin and C18 internal olefin. The internal olefin is a p or higher olefin, such as a p-olefin. Internal olefins are sometimes known as isomerised olefins may be prepared by isomerisation of an a-olefin. Typically, terminal olefins and internal olefins may be provided as a mixture of isomers. Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the double bonds in terminal olefins are terminal double bonds. Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the terminal double bonds in the terminal olefins are at the a-position (i.e. they are a-alkene groups). Suitably at least 70 mol%, such as at least 80 mol%, preferably at least 90 mol%, for example at least 95 mol% of the double bonds in internal olefins are non-terminal double bonds. Suitably, one of R5 and R6, R7 and R8, orR9, R10, R11, R12, R13, R14, and R15 may be an alkyl group or an alkenyl group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other (or others) may be hydrogen. Examples of cyclic anhydride monomers of the formula (I), (II) or (III) wherein any of R1 and R2, R3 and R4, orR5, R6, R7, R8, R9, R10, and R11 represents hydrogen or a C6-30, such as a Cs-24, branched or unbranched alkyl or alkenyl group include succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), tetrapropenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, nonenyl succinic anhydride, C20-24 alkenyl succinic anhydride, C15-18 internal olefin-derived alkenyl succinic anhydride, C16 internal olefin-derived alkenyl succinic anhydride, C16 terminal olefin-derived alkenyl succinic anhydride, maleic anhydride and glutaric anhydride. The cyclic anhydride monomers of the formula (III), (IV) or (V) wherein any of R5 and R6, R7 and R8, orR9, R10, R11, R12, R13, R14, and R15 represents hydrogen or a C6-30, such as a Cs-24, branched or unbranched alkyl or alkenyl group may be selected from succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), tetrapropenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, nonenyl succinic anhydride, C20-24 alkenyl succinic anhydride, maleic anhydride and glutaric anhydride. When any of R5 and R6, or R7 and R8, orR9, R10, R11, R12, R13, R14, and R15, together with the atoms to which they are attached represent an optionally substituted cyclic group, the cyclic group so formed may be mono or polycyclic (preferably mono or bicyclic) and may be aromatic or non-aromatic. Examples of aromatic groups that may be so formed include benzene and naphthalene. Examples of non-aromatic groups that may be so formed include cyclopentane, cyclohexane, and cyclooctane. Any of R9, R10, R11, R12, R13, R14, and R15 together with the atoms to which they are attached may represent an optionally substituted cyclic group. Any of R9, R10, R11, R12, R13, R14, and R15 not representing a cyclic group are independently selected from hydrogen, an alkyl group and an alkenyl group as described herein. Two, three, four, five, or six of R9, R10, R11, R12, R13, R14, and R15 together with the atoms to which they are attached may represent an optionally substituted cyclic group. Suitably at least R9 and R11, or R9 and R13, or R9 and R15, or R11 and R13, or R11 and R15, or R9, R11 and R13, or R9, R11 and R15 together with the atoms to which they are attached may represent an optionally substituted cyclic group. For the avoidance of doubt, when any of R9, R10, R11, R12, R13, and R14 together with the atoms to which they are attached represent an optionally substituted cyclic group, one or more of R9, R10, R11, R12, R13, and R14 may contribute to one or more double bonds (for example, aromaticity) in the cyclic group. For example, R12 and R14 may together form a carbon-carbon double bond, which may form part of an aromatic cyclic group. The optionally substituted cyclic group represented by R5 and R6, or R7 and R8, or any of R9, R10, R11, R12, R13, R14, and R15, together with the atoms to which they are attached (when present) may be optionally substituted with any suitable substituent(s), such as for example one or more substituents independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4 or Ca-24, alkoxy-carbonyl), alkenyloxy-carbonyl (for example C2-30, preferably C2-24, such as C2-4 or Ca-24, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. The optionally substituted cyclic group represented by R5 and R6, or R7 and R8, or any of R9, R10, R11, R12, R13, R14, and R15, together with the atoms to which they are attached (when present) may alternatively be substituted by groups which form a further cyclic anhydride group. An example of such a cyclic anhydride is pyromellitic dianhydride. However, in some embodiments the cyclic anhydride monomers of the formula (III), (IV) or (V) contain a single (i.e. only one) anhydride group. In such embodiments, the optionally substituted cyclic group represented by R5 and R6, or R7 and R8, orR9, R10, R11, R12, R13, and R14, together with the atoms to which they are attached (when present) may not be substituted by a further cyclic anhydride group. Examples of suitable cyclic anhydrides of formula (III) in which R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted 1,2-cyclohexanedicarboxylic anhydride and 1,3-cyclopentanedicarboxylic anhydride. 1,2-Cyclohexanedicarboxylic anhydride is preferred. Examples of suitable anhydrides of formula (IV) in which R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted phthalic anhydride, pyromellitic dianhydride, 1,2-naphthalic anhydride and 2,3-naphthalic anhydride. Examples of a substituted phthalic anhydride may include 1,2,4-benzenetricarboxylic anhydride, and 6-((octadec-9-en-1-yloxy)carbonyl)-1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid. Examples of suitable anhydrides of formula (V) in which any of R9, R10, R11, R12, R13, R14, and R15 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group include optionally substituted 1,8-naphthalic anhydride and homophthalic anhydride. Preferred cyclic anhydrides include one or more cyclic anhydrides of formula (III) wherein R5 and R6 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkyl or alkenyl group, or wherein R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (IV) wherein R7 and R8 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkyl or alkenyl group, or wherein R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (V) wherein X is CR13R14, O, or S and R9, R10, R11, R12, R13, and R14 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, an alkyl group or alkenyl group, and / or wherein any of R9, R10, R11, R12, R13, and R14 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group. More preferred cyclic anhydrides include one or more cyclic anhydrides of formula (III) wherein R5 and R6 are each independently selected from hydrogen and a Cs-3o, such as a Cs-24, alkenyl group, or wherein R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (IV) wherein R7 and R8 are both hydrogen, or wherein R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group; or of formula (V) wherein X is CR13R14, O, or S and R9, R10, R11, R12, R13, and R14 are each hydrogen, and / or wherein any of R9, R10, R11, R12, R13, and R14 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group. At least one of the second monomers may be a cyclic anhydride of formula (III), (IV) or (V) wherein at least one of R5 and R6, or at least one of R7 and R8, or at least one of R9, R10, R11, R12, R13, R14, and R15, is a Ce-30, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin). Preferably, at least one of the second monomers may be a cyclic anhydride of formula (III), (IV) or (V) wherein at least one of R5 and R6, or at least one of R7 and R8, or at least one of R9, R10, R11, R12, R13, R14, and R15, is a Cs-3o, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other (or others) is (or are) hydrogen. For example, the cyclic anhydride may be an anhydride of formula (III) wherein R5 and R6 are both hydrogen (i.e. the cyclic anhydride may be succinic anhydride). For example, the cyclic anhydride may be an anhydride of formula (IV) wherein R7 and R8 are both hydrogen (i.e. the cyclic anhydride may be maleic anhydride). For example, the cyclic anhydride may be an anhydride of formula (V) in which X is CR13R14 and R9, R10, R11, R12, R13, and R14 each represent hydrogen (i.e. the cyclic anhydride may be glutaric anhydride). For example, the cyclic anhydride may be an anhydride of formula (V) in which X is O and R9, R10, R11, and R12 each represent hydrogen (i.e. the cyclic anhydride may be diglycolic anhydride). For example, the cyclic anhydride may be an anhydride of formula (V) in which X is S and R9, R10, R11, and R12 each represent hydrogen (i.e. the cyclic anhydride may be thiodiglycolic anhydride). For example, the or each cyclic anhydride may be an anhydride of formula (III) wherein R5 and R6 are both hydrogen or wherein one of R5 and R6 is an alkyl or alkenyl group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other of R5 and R6 is hydrogen. For example, the or each cyclic anhydride may be an anhydride of formula (III) wherein R5 and R6 are both hydrogen or wherein one of R5 and R6 is a Cs-3o, such as a Cs-24, alkyl or alkenyl (more preferably alkenyl) group (such as an alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin) and the other of R5 and R6 is hydrogen. Examples of such cyclic anhydride compounds include succinic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride and octenyl succinic anhydride. Preferably, the or each cyclic anhydride may be an anhydride of formula (III) wherein one of R5 and R6 is an alkenyl group, such as a Ce-30 (preferably Cs-24) alkenyl group (such as a Ce-30 (preferably Cs-24) alkenyl group derived from a terminal olefin or an internal olefin, preferably an internal olefin), and the other of R5 and R6 is hydrogen. Examples of such cyclic anhydride compounds include C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride and octenyl succinic anhydride. Preferably, the cyclic anhydride may be dodecenyl succinic anhydride, such as (2-dodecen-1-yl)succinic anhydride. Preferably, the cyclic anhydride may be octadecenyl succinic anhydride. The or each cyclic anhydride may be an anhydride of formula (III) wherein one of R5 and R6 is hydrogen and the other of R5 and R6 is a polyisobutenyl group, for example wherein the polyisobutenyl group suitably has a number average molecular weight of from 100 to 2000, preferably from 100 to 1000, for example 260 or 550. Preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (III) or (IV) wherein R5 and R6, or R7 and R8, together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic or a non-aromatic group and is mono or polycyclic. Preferably, the or each cyclic anhydride may be an anhydride of formula (III) wherein R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is a non-aromatic (for example saturated) mono or bicyclic group. More preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (III) wherein R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is a non-aromatic (for example saturated) monocyclic group, such as a cyclohexane group. Preferably, the or each cyclic anhydride may be an anhydride of formula (IV) wherein R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic mono or bicyclic group, such as a benzene or naphthalene group. More preferably, the or each cyclic anhydride may be a cyclic anhydride of formula (IV) wherein R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic monocyclic group, such as a benzene group. Preferably, the or each cyclic anhydride may be an anhydride of formula (V) wherein X is CR13R14 and R9, R10, R11, R12, R13, and R14 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic bicyclic group, such as a naphthalene group; or R11 and R12 are hydrogen and R9, R10, R13 and R14 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic monocyclic group, such as a benzene group. More preferably, the or each cyclic anhydride may be an anhydride of formula (V) wherein X is CR13R14 and R9, R10, R11, R12, R13, and R14 together with the carbon atoms to which they are attached represent an optionally substituted cyclic group, wherein the cyclic group is an aromatic bicyclic group, such as a naphthalene group. When the cyclic anhydride is an anhydride of formula (III) wherein R5 and R6 together with the carbon atoms to which they are attached represent an optionally substituted cyclohexane group, the cyclic anhydride may be of the formula (IIIA): wherein n5 is an integer from 0 to 4 and each R16 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups, or when n5 is 2 the two R16 groups may represent a further cyclic anhydride group (such as a further succinic anhydride group). In some embodiments, the cyclic anhydride of formula (IIIA) contains a single (i.e. only one) anhydride group. In such embodiments, two R16 groups may not represent a further cyclic anhydride group. Examples of suitable succinic anhydrides of formula (IIIA) include 1,2-cyclohexanedicarboxylic anhydride. When the cyclic anhydride is an anhydride of formula (IV) wherein R7 and R8 together with the carbon atoms to which they are attached represent an optionally substituted benzene group, the cyclic anhydride may be of the formula (IVA): wherein n6 is an integer from 0 to 4 and each R17 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups, or when n6 is 2 the two R17 groups may represent a further cyclic anhydride group (such as a further succinic anhydride group). When R17 represents a alkoxy-carbonyl (for example C1-30, preferably Ca-24, alkoxy-carbonyl) or alkenyloxy-carbonyl (for example C2-30, preferably Ca-24, alkenyloxy-carbonyl), substituent, the alkoxy-carbonyl or alkenyloxy-carbonyl group may be of the formula -C(O)OR17 wherein R17 is a C1-30, preferably Ca-24, alkyl group or a C2-30, preferably Ca-24, alkenyl group. Suitably R17 may represent an oleyl group. Examples of suitable succinic anhydrides of formula (IVA) include phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-naphthalic anhydride and 2,3-naphthalic anhydride, and 6-((octadec-9-en-1-yloxy)carbonyl)-1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid. When the cyclic anhydride is an anhydride of formula (V) wherein X is CR13R14 and R9, R10, R11, R12, R13, and R14 together with the carbon atoms to which they are attached represent an optionally substituted naphthalene group, the cyclic anhydride may be of the formula (VA): wherein each of m and m’ is independently an integer from 0 to 3 and each of R18 and R19 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example Ci-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxy-carbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. Examples of suitable succinic anhydrides of formula (VA) include 1,8-naphthalic anhydride. When the cyclic anhydride is an anhydride of formula (V) wherein X is CR13R14, R11 and R12 are hydrogen and R9, R10, R13 and R14 together with the carbon atoms to which they are attached represent an optionally substituted benzene group, the cyclic anhydride may be of the formula (VB): wherein m” is an integer from 0 to 4 and each R20 (when present) is independently selected from alkyl (for example C1-30, preferably C1-24, such as C1-4, alkyl), alkenyl (for example C2-30, preferably C2-24, such as C2-4, alkenyl), alkoxy (for example C1-30, preferably C1-24, such as C1-4, alkoxy), alkenyloxy (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy), carboxy, alkoxy-carbonyl (for example C1-30, preferably C1-24, such as C1-4, alkoxy-carbonyl), alkenyloxycarbonyl (for example C2-30, preferably C2-24, such as C2-4, alkenyloxy-carbonyl), hydroxy, halo (for example chloro or fluoro), nitro and cyano groups. Examples of suitable succinic anhydrides of formula (VB) include homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a Ce-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, glutaric anhydride, a C6-30 alkenyl succinic anhydride such as C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, octadecyl succinic anhydride, or octyl succinic anhydride, and a branched alkenyl succinic anhydride such as tetrapropenyl succinic anhydride or polyisobutenyl succinic anhydride. Suitably, the or each cyclic anhydride may be selected from one or more of phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride and homophthalic anhydride. More suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride, homophthalic anhydride and glutaric anhydride. More suitably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, and glutaric anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2- dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, octenyl succinic anhydride, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride and 1,8-naphthalic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of succinic anhydride, maleic anhydride, C20-24 alkenyl succinic anhydride, dodecenyl succinic anhydride (such as (2-dodecen-1-yl)succinic anhydride), nonenyl succinic anhydride, octadecenyl succinic anhydride, and octenyl succinic anhydride. Preferably, the or each cyclic anhydride may be selected from one or more of phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, 1,2-cyclohexanedicarboxylic anhydride and 1,8-naphthalic anhydride. The cyclic anhydride compounds discussed herein may be commercially available or may be prepared using procedures well known in the art. For example, alkenyl substituted succinic anhydrides are typically prepared by the reaction of an alkene with maleic anhydride. Preferably, the or each cyclic anhydride may be independently selected from a C6-30 alkyl or alkenyl substituted succinic anhydride, phthalic anhydride and pyromellitic dianhydride. Preferably, the or each cyclic anhydride may be independently selected from a C6-30 alkyl or alkenyl substituted succinic anhydride. Preferably, the or each cyclic anhydride may be independently selected from (2-dodecen-1-yl)succinic anhydride, nonenyl succinic anhydride, octadecenyl succinic anhydride, phthalic anhydride and pyromellitic dianhydride. Preferably, the or each cyclic anhydride may be independently selected from (2-dodecen-1-yl)succinic anhydride, nonenyl succinic anhydride, and octadecenyl succinic anhydride. Preferably, the or each cyclic anhydride may be independently selected from phthalic anhydride and pyromellitic dianhydride. One or more of the second monomers may be a polyol. The term polyol is used to refer to any compound including two or more hydroxy (OH) functional groups. In some embodiments the or each polyol may comprise carbon, hydrogen and oxygen atoms, and optionally additionally nitrogen atoms. In other embodiments, the or each polyol may consist essentially of or consist of carbon, hydrogen and oxygen atoms. Suitable polyols for preparing the polymer may be compounds having from 2 to 10, preferably from 2 to 6, more preferably 2 or 3, most preferably 2, hydroxy groups. Suitable polyols may include one or more of a polyol of formula (VI): H-(OR21)P-OH (VI) wherein each R21 is independently an optionally substituted hydrocarbylene group and p is an integer of at least 1. When p is an integer of greater than 1, the polyol of formula (VI) may comprise groups R21 that are all the same or may comprise groups R21 that are different. Suitably, each R21 in the formula (VI) may be the same. Preferably p is an integer from 1 to 140, such as from 1 to 110, from 1 to 40 or from 1 to 10. For example, suitable polyols may include one or more of a polyol of formula (VIA): H-(OR22)q-OH (VIA) wherein each R22 is independently an optionally substituted alkylene group and q is an integer of at least 1. When q is an integer of greater than 1, the polyol of formula (VIA) may comprise groups R22 that are all the same or may comprise groups R22 that are different. Suitably, each R22 in the formula (VIA) is the same. Preferably q is an integer from 1 to 140, such as from 1 to 110, from 1 to 40 or from 1 to 10. When the polyol of formula (VI) or (VIA) contains a substituted hydrocarbylene or alkylene group, any suitable substituent may be present, such as for example a carboxy or amido substituent. The polyol of formula (VIA) may have more than 2 hydroxy groups and the group R22 may be a hydroxy substituted alkylene group. Each hydroxy substituted alkylene group R22 may have 1,2 or more hydroxy groups. Each hydroxy substituted alkylene group R22 may preferably have 1 hydroxy group. The polyol of formula (VIA) may have 2 hydroxy groups and the group R22 may be an optionally substituted alkylene group wherein the optional substituent is not hydroxy. The polyol of formula (VI) or of formula (VIA) may be a sugar derived compound in which R21 or R22 includes one or more hydroxy residues. The or each R21 or R22 may represent a cyclic alkylene unit. One or more heteroatoms (for example oxygen atoms) may be present in the cyclic alkylene unit. For example the unit may contain an ether linkage. Suitably the or each R21 or R22 may be one or more saccharide units or may be substituted with one or more saccharide units. Suitably the or each R21 or R22 may be an unsubstituted alkylene group. Preferably the or each R21 or R22 is an optionally substituted alkylene group having from 1 to 50, such as from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, suitably from 1 to 12 or from 1 to 10, for example from 2 to 6, carbon atoms. Preferably the or each R21 or R22 is an unsubstituted alkylene group having from 1 to 50, preferably from 1 to 20, more preferably from 1 to 12 or from 1 to 10, suitably from 2 to 6 carbon atoms. Each R21 or R22 may be straight chained or branched. Suitably the or each R21 or R22 may be an ethylene, propylene, butylene, pentylene, hexylene or dodecylene group. When R21 or R22 has more than 2 carbon atoms any isomer may be present. Preferably R21 or R22 is an ethylene or a propylene group, most preferably an ethylene group. When q is 1, R22 may be a group of formula (CH2)x wherein x is from 2 to 12, preferably from 3 to 12. Suitably when q is 1, R22 may be a straight chain or branched optionally substituted alkylene group and the polyol may be selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, 1,12-dodecanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, 2,2-bis(hydroxymethyl)propionic acid, pentaerythritol, sorbitol, xylitol, glycerol and neopentyl glycol. Suitably when q is 1, R22 may be a straight chain or branched alkylene group having from 2 to 12, preferably from 3 to 12, carbon atoms. Suitable compounds of this type include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3- butanediol, 1,6-hexanediol, 1,12-dodecanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, pentaerythritol and neopentyl glycol. 1,6-hexanediol is a preferred polyol. Suitably when q is 1, R22 may be a branched alkylene group having from 2 to 12, preferably from 3 to 12, carbon atoms. Suitable compounds of this type include propylene glycol, 1,2-butanediol, 1,3-butanediol, trimethylolpropane, 2-ethyl-1,3,-hexanediol, 2,2-diethyl-1,3-propanediol, pentaerythritol and neopentyl glycol. Suitably when q is 2 or more, the or each R22 may be a straight chain or branched alkylene group and the polyol may, for example, be selected from diglycerol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol. Suitably when q is 2 or more, the or each R22 may be a straight chain or branched alkylene group having from 2 to 4, preferably 2 or 3, carbon atoms. Suitable compounds of this type include diethylene glycol, triethylene glycol, di propylene glycol, tripropylene glycol, polyethylene glycol (PEG), for example having a molecular weight of from 150 to 6000, and polypropylene glycol (PPG), for example having a molecular weight of from 400 to 2000. Preferred compounds of this type include polyethylene glycol (PEG), for example having a molecular weight of from 150 to 6000, and polypropylene glycol (PPG), for example having a molecular weight of from 400 to 2000 (especially PPG). Suitable polyols may include one or more of PEG 6000, PEG 1500, PEG 1000, PEG 600, PEG 400, PEG 200, PPG 2000, PPG 1000 and PPG 425. The or each R21 or R22 may comprise a mixture of isomers. For example when R21 or R22 is propylene, the polyol may include moieties -CH2CH(CH3)- and -CH(CH3)CH2- in any order within the chain. R21 or R22 may comprise a mixture of different groups for example ethylene, propylene or butylene units. The or each R22 may be an ethylene, propylene or butylene group. For example, the or each R22 may be an n-propylene or n-butylene group or an isopropylene or isobutylene group. For example the or each R22 may be -CH2CH2-, -CH2CH(CH3)-, - CH(CH3)CH2-, CH2CH2CH2-, -CH2C(CH3)2-, -CH2CH2CH2CH2-, -CH(CH3)CH(CH3)- or -CH2CH(CH2CH3)-. Preferably R22 is selected from -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2- or -CH2CH(OH)CH2, more preferably from -CH2CH2-, and-CH2CH2CH2-. Suitably the polyol of formula (VI) or (VIA) may be a sugar derived alcohol, for example, glucose, fructose, trehalose, sucrose, lactose, maltose or sorbitol, preferably sorbitol. Suitably the polyol of formula (VI) may be selected from one or more of 1,12-dodecanediol, 1,6-hexanediol, trimethylolpropane, neopentyl glycol, polyethylene glycol (such as PEG 6000, PEG 1500, PEG 1000, PEG 600, PEG 400, PEG 200), polypropylene glycol (such as PPG 2000, PPG 1000, PPG 425), sorbitol, trimethylolpropane and xylitol. Suitably, the polyol, for example of formula (VI), may be an ester of glycerol (also known as a glyceride) and a hydroxycarboxylic acid. The ester of glycerol may be a mono-, di- or triglyceride, suitably a tri-glyceride. Suitably, the hydroxycarboxylic acid comprises one or more hydroxyl groups and one or more carboxylic acid groups. The hydroxycarboxylic acid may be a monocarboxylic acid comprising one or more hydroxyl groups. The hydroxycarboxylic acid may be of the formula R23COOH, wherein R23 is a hydroxylsubstituted hydrocarbyl group. R23is suitably a hydroxy-substituted alkyl, alkenyl or alkaryl group, preferably a hydroxy-substituted alkyl or alkenyl group. R23 suitably comprises from 1 to 25 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 17 carbon atoms. Suitably, the hydroxycarboxylic acid may be selected from glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), 2,2-bis(hydroxymethyl)propionic acid, mandelic acid or ricinoleic acid. Preferably, the hydroxycarboxylic acid or the cyclic ester thereof may be selected from glycolic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid or citric acid. More preferably, the hydroxycarboxylic acid or the cyclic ester thereof is ricinoleic acid. Preferably, when the polyol is an ester of glycerol, the polyol may be a mono-, di- or tri-glyceride of ricinoleic acid. Most preferably, when the polyol is an ester of glycerol, the polyol may be a tri-glyceride of ricinoleic acid, such as castor oil. Suitable polyols may include one or more of an alkoxylated polyol of formula (VI) or (VIA). These polyols may be the reaction product of a polyol of formula (VI) or (VIA) and one or more alkylene oxides, such as ethylene oxide or propylene oxide. Such alkoxylated polyols may include polyoxyethylene (80) sorbitan monooleate (also known as Tween® 80) and 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate. Preferably, the or each polyol may be independently selected from castor oil, 1,6-hexanediol, sorbitol, neopentyl glycol and a polyalkylene glycol (such as polyethylene glycol (PEG) or polypropylene glycol (PPG), for example PEG 200 or PPG 2000). Preferably, the or each polyol may be independently selected from 1,6-hexanediol and a polyalkylene glycol (such as polyethylene glycol (PEG) or polypropylene glycol (PPG), for example PEG 200 or PPG 2000). More preferably, the or each polyol may be independently selected from 1,6-hexanediol and polypropylene glycol (PPG), for example PPG 2000). Preferably, the or each polyol may be independently selected from castor oil, 1,6-hexanediol, sorbitol, neopentyl glycol and a polyalkylene glycol (such as PEG 200). When the or each polyol comprises carbon, hydrogen, oxygen and nitrogen atoms, the or each polyol may comprise two or more (such as 2 or 3) hydroxy groups and one or more (suitably one) amine groups. The amine groups may suitably be secondary or tertiary amines. Preferably the amine groups are tertiary amines. These polyols may be referred to herein as nitrogen containing polyols. For example, suitable nitrogen containing polyols may include one or more of a polyol of formula (VI I) or a derivative thereof: Nr24r25r26 (VII) wherein R24, R25 and R26 are each independently selected from hydrogen, hydroxyalkyl and hydrocarbyl, provided that at least two of R24, R25 and R26 represents a hydroxyalkyl group. Preferably, the at least two of R24, R25 and R26 that represent a hydroxyalkyl group are the same. For example, in the compounds of formula (VII), R24 and R25 may each represent hydroxyalkyl and R26 may represent hydrogen, hydroxyalkyl or hydrocarbyl. In the formula (VII), the hydroxyalkyl group may contain from 1 to 8, such as from 1 to 4, such as 2 or 3, carbon atoms. For example, each hydroxyalkyl group may be hydroxyethyl or hydroxypropyl, particularly hydroxyethyl. In the formula (VII), the hydrocarbyl group (when present) may represent any suitable such group, such as an alkyl group, for example an alkyl group containing from 1 to 10, such as from 1 to 6 or from 1 to 4, carbon atoms. Thus, the hydrocarbyl group may represent a methyl, ethyl, propyl or butyl group (especially butyl or methyl). For example, in the compounds of formula (VII), R24 and R25 may each represent hydroxyalkyl and R26 may represent hydrogen, hydroxyalkyl or hydrocarbyl (especially hydrogen or hydrocarbyl, more especially hydrocarbyl). Preferably in the compounds of formula (VII), R24 and R25 both represent hydroxyethyl and R26 represents hydrogen or hydrocarbyl, such as a hydrocarbyl group containing from 1 to 6, or from 1 to 4, carbon atoms. Preferably in the compounds of formula (VII), R24 and R25 both represent hydroxyethyl and R26 represents hydrogen or an alkyl group containing from 1 to 6, or from 1 to 4, carbon atoms (especially methyl). Examples of suitable nitrogen containing polyols include N-methyl diethanolamine, N-butyl diethanolamine, triethanolamine and diethanolamine, and derivatives thereof. References herein to nitrogen containing polyols include derivatives thereof, such as a corresponding quaternary compound. Thus, as example of a suitable derivative of a nitrogen containing polyol is tris(2-hydroxyalkyl)methylammonium compound, for example tris(2-hydroxyethyl)methylammonium methylsulfate, which is a quaternary ammonium salt of triethanolamine. Preferably, the or each nitrogen containing polyol may be independently selected from N-butyl diethanolamine, diethanolamine and N-methyl diethanolamine, and derivatives (for example quaternary ammonium salts) thereof. Further examples of suitable nitrogen containing polyols include those formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate, such as glycerol carbonate or gluconolactone, with a suitable primary or secondary amine compound, such as ethanolamine, dipropylamine, hexylamine, dodecylamine, phenethylamine, dipropylamine, ethylenediamine, or a polyether polyamine. Suitable polyether amines may include polyether monoamines (such as for example Jeffamine M-1000) and polyether polyamines (such as for example Jeffamine ED-600). As the skilled person would appreciate, the reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound will result in a ring opening reaction to form a compound such as a N-carbamoyl polyol or an amido polyol. The or each polyol may be selected from one or more polyol of the formula (VI) or (VIA) as defined herein (including an ester of glycerol and a hydroxycarboxylic acid (such as castor oil)), one or more of an alkoxylated polyol of formula (VI) or (VIA) as defined herein, one or more nitrogen containing polyol as defined herein (including compounds of the formula (VII)) and one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. Preferably, the or each polyol may be selected from one or more polyol of the formula (VI) or (VIA) as defined herein (including an ester of glycerol and a hydroxycarboxylic acid (such as castor oil)), one or more of an alkoxylated polyol of formula (VI) or (VIA) as defined herein, one or more nitrogen containing polyol of the formula (VII) as defined herein and one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. More preferably, the or each polyol may be selected from one or more polyol of the formula (VI) or (VIA) as defined herein (such as an ester of glycerol and a hydroxycarboxylic acid , for example castor oil), and one or more nitrogen containing polyol of the formula (VII) as defined herein. In one embodiment, the or each polyol may be selected from one or more polyol of the formula (VI) or (VIA) as defined herein, such as an ester of glycerol and a hydroxycarboxylic acid (for example castor oil) / In another embodiment, the or each polyol may be selected from one or more of an alkoxylated polyol of formula (VI) or (VIA) as defined herein. In one embodiment, the or each polyol may be selected from one or more polyol of the formula (VI) or (VIA) as defined herein, such as an ester of glycerol and a hydroxycarboxylic acid (for example castor oil) and from one or more of an alkoxylated polyol of formula (VI) or (VIA) as defined herein. In another embodiment, the or each polyol may be selected from one or more nitrogen containing polyol as defined herein (including compounds of the formula (VII)). In another embodiment, the or each polyol may be selected from one or more polyol formed by reaction of a hydroxy substituted cyclic ester or cyclic carbonate with a suitable primary or secondary amine compound. One or more of the second monomers may be a polycarboxylic acid or a reactive equivalent thereof. The polycarboxylic acid may comprise two or more carboxylic acid groups, such as two or three carboxylic acid groups. Preferred polycarboxylic acids are dicarboxylic acids. The polycarboxylic acid may be aliphatic or aromatic. The aliphatic polycarboxylic acid may be cycloaliphatic. The aliphatic polycarboxylic acid may be saturated or unsaturated. By the term “unsaturated” we mean that the polycarboxylic acid comprises one or more carbon-carbon double bonds. The polycarboxylic acid may comprise one or more heteroatoms other than the oxygen atoms in the carboxylic acid groups. By the term “heteroatoms” we mean atoms other than carbon or hydrogen, such as oxygen, nitrogen and sulfur atoms. For example, the polycarboxylic acid may comprise one or more moieties selected from hydroxy groups, amino groups, ether groups, and / or thioether groups. The polycarboxylic acid may be of the formula HOOC(CR272)n7COOH, wherein n7 is from 0 to 30;and each R27 is independently hydrogen or a substituent; and / or two R27 groups on the same carbon atom may be taken together to form a methylene (=CH2) group; and / or when n7 is two or more, two R27 groups on adjacent carbon atoms may be taken together to form a double bond. n7 is suitably from 1 to 20, preferably from 2 to 16, more preferably from 2 to 12, for example from 2 to 10. Each (C R272) group can be the same or different. Unless otherwise specified, the terms “each R27”, “R27 groups” and the like are intended to refer to all instances of the “R27” group in the formula HOOC(CR272)n7COOH, Each R27 may be hydrogen. Alternatively, one or two R27 groups may be a substituent and the remaining R27 groups may be hydrogen. Any suitable substituent may be used as R27. The substituent may be a hydrocarbyl group or a heteroatom-containing group. Examples of suitable substituents include hydroxy groups, amino groups, carboxyl groups, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups, wherein the alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and alkaryl groups are optionally substituted with one or more of a hydroxy group, an amino group, and / or a carboxyl group. One or two of the R27 groups may be a hydroxy group. Another of the R27 groups may optionally be a carboxyl group or a carboxyl-substituted methyl group, and the remaining R27 groups are suitably hydrogen. Suitably, one or two of the R27 groups may be a hydroxy group, another of the R27 groups may be a carboxyl group or a carboxyl-substituted methyl group, and the remaining R27 groups may be hydrogen; or one or two of the R27 groups may be a hydroxy group and the remaining R27 groups may be hydrogen. The polycarboxylic acid may be malic acid, tartaric acid, or citric acid. One or two R27 groups may be an alkyl or alkenyl group. Preferably, one R27 group is an alkyl or alkenyl group. The remaining R27 groups are suitably hydrogen. Each alkyl or alkenyl group may contain from 6 to 30, such as from 8 to 24, carbon atoms. The polycarboxylic acid may be an alkyl or alkenyl substituted succinic acid, preferably an alkenyl substituted succinic acid. Examples of such polycarboxylic acids include C20-24 alkenyl succinic acid, dodecenyl succinic acid (such as (2-dodecen-1-yl)succinic acid), nonenyl succinic acid, octadecenyl succinic acid and octenyl succinic acid. One R27 group may be a polyisobutenyl group and the remaining R27 groups may be hydrogen. The polyisobutenyl group suitably has a number average molecular weight of from 100 to 2000, preferably from 100 to 1000, for example 260 or 550. The polycarboxylic acid may be a polyisobutenyl succinic acid, for example wherein the polyisobutenyl group has a number average molecular weight of 260 or 550. Two R27 groups on the same carbon atom may be taken together to form a methylene (=CH2) group. The polycarboxylic acid may comprise one or more such methylene groups. Two R27 groups on the same carbon atom may be taken together to form a methylene (=CH2) group and the remaining R27 groups may be hydrogen. The polycarboxylic acid may be itaconic acid. When n7 is 2 or more, two R27 groups on adjacent carbon atoms may be taken together to form a double bond. The polycarboxylic acid may comprise one or more such double bonds. The double bond may be in a cis or trans configuration. Two R27 groups on adjacent carbon atoms may be taken together to form a double bond and the remaining R27 groups may be hydrogen. The polycarboxylic acid may be maleic acid or fumaric acid. The polycarboxylic acid may be of the formula HOOC(CH2)n8COOH, wherein n8 is from 0 to 30. n8 is suitably from 1 to 20, preferably from 2 to 16, more preferably from 4 to 12, for example from 5 to 10. The polycarboxylic acid may be selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, or dodecanedioic acid. Preferably, the polycarboxylic acid may be selected from pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, or dodecanedioic acid. The polycarboxylic acid may be of the formula HOOC(CH2)miX(CH2)m2COOH, wherein m1+m2 is from 0 to 30 and X is O, S, or NR28 wherein R28 is hydrogen or a hydrocarbyl group. m1+m2 is suitably from 1 to 20, preferably from 2 to 16, more preferably from 2 to 12, for example from 2 to 6. ml and m2 may each independently be from 0 to 30, suitably from 1 to 19, preferably from 1 to 15, more preferably from 1 to 11, for example from 1 to 5. R28 may be a hydrocarbyl group, such as an alkyl or alkenyl group. The hydrocarbyl group may contain from 1 to 12 carbon atoms, preferably from 1 to 6 carbon atoms. Preferably, R28 is hydrogen. X is preferably O or S. The polycarboxylic acid may be selected from diglycolic acid, thiodiglycolic acid, 3,3’-thiodipropanoic acid, or iminodiacetic acid, preferably from diglycolic acid or thiodiglycolic acid. A preferred polycarboxylic acid is diglycolic acid. The polycarboxylic acid may be of the formula HOOCCH2(OCH2CHR29)x2OCH2COOH, wherein x2 is from 1 to 30 and each R29 is independently hydrogen or a hydrocarbyl group. x2 is suitably from 1 to 20, preferably from 2 to 16, more preferably from 4 to 14, for example from 6 to 12, such as 10. Each R29 may independently be a hydrocarbyl group, such as an alkyl group. The alkyl group may contain from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. The alkyl group is preferably methyl. In some embodiments, a portion of R29 groups are hydrocarbyl groups (such as methyl groups) and the remaining R29 groups are hydrogen. Preferably, each R29 is hydrogen. The polycarboxylic acid may be a poly(ethylene glycol)bis(carboxymethyl) ether. The poly(ethylene glycol)bis(carboxymethyl) ether may contain from 1 to 20 ethylene oxide units (i.e. -CH2CH2O-), preferably from 2 to 16 ethylene oxide units, more preferably from 4 to 14 ethylene oxide units, for example from 6 to 12 ethylene oxide units, such as 10 ethylene oxide units. The polycarboxylic acid may be a poly(ethylene glycol)bis(carboxymethyl) ether containing 10 ethylene oxide units. The polycarboxylic acid may comprise a cyclic group. The cyclic group may be substituted, for example with alkyl or alkenyl groups. The carboxyl groups of the polycarboxylic acid may be attached directly to the cyclic group, or via an alkyl or alkenyl group. The cyclic group may be a cycloaliphatic group. Examples of cycloaliphatic groups include cyclohexane and cyclohexene. The polycarboxylic acid may be 1,2-cyclohexanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid. The cyclic group may be an aromatic group. Examples of aromatic groups include benzene and naphthalene. The polycarboxylic acid may be selected from phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 1,2,4-benzenetricarboxylic acid, pyromellitic acid, 1,2-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid. 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, or 2,7-naphthalenedicarboxylic acid. The polycarboxylic acid may be a dimer acid. Such compounds are formed from the dimerisation of unsaturated acids, for example unsaturated fatty acids having from 6 to 50, suitably from 8 to 40, preferably from 10 to 36, for example from 10 to 20 carbon atoms, or from 16 to 20 carbon atoms. The dimer acid may be hydrogenated or unhydrogenated. Preferably, the dimer acid is hydrogenated. The dimer acid may have from 12 to 100 carbon atoms, preferably from 16 to 72 carbon atoms such as from 20 to 40 carbon atoms, for example from 32 to 40 carbon atoms. Preferred dimer acids comprise C36 dimer acids such as those prepared by dimerising oleic acid, linoleic acid and mixtures comprising oleic and linoleic acid, for example, tall oil fatty acids. Preferably, the dimer acid comprises a dimer acid prepared by dimerising oleic acid. The dimer acid may be a hydrogenated C36 dimer acid. A reactive equivalent of the polycarboxylic acid may be used. By the term “reactive equivalent”, we mean a compound that results in the same reaction product as the corresponding polycarboxylic acid. Suitable reactive equivalents include acid chlorides and esters of the polycarboxylic acids described herein. The reactive equivalent may be an acid chloride of the polycarboxylic acid. The acid chloride of the polycarboxylic acid suitably does not comprise any free carboxylic acid groups. The reactive equivalent may be an ester of the polycarboxylic acid. The ester of the polycarboxylic acid suitably does not comprise any free carboxylic acid groups. The ester of the polycarboxylic acid is suitably a hydrocarbyl ester, such as an alkyl ester, an alkenyl ester, an aryl ester, an aralkyl ester, or an alkaryl ester. Preferably the ester is an alkyl ester. The alkyl ester is suitably formed by reacting the polycarboxylic acid with an alkanol. The alkanol suitably contains from 1 to 10 carbon atoms, such as from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms. The alkanol is preferably methanol. The alkyl ester is preferably a methyl ester. Suitably, the or each polycarboxylic acid or the reactive equivalent thereof may be selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, maleic acid, fumaric acid, malic acid, tartaric acid, citric acid, C20-24 alkenyl succinic acid, dodecenyl succinic acid (such as (2-dodecen-1-yl)succinic acid), nonenyl succinic acid, octadecenyl succinic acid, octenyl succinic acid, polyisobutenylsuccinic acid, itaconic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 1,2,4-benzenetricarboxylic acid, pyromellitic acid, 1,2-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diglycolic acid, thiodiglycolic acid, 3,3’-thiodipropanoic acid, iminodiacetic acid, poly(ethylene glycol)bis(carboxymethyl) ether, a dimer acid, or an acid chloride or ester thereof. Suitably, the or each polycarboxylic acid or the reactive equivalent thereof may be selected from oxalic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, malic acid, tartaric acid, citric acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid, diglycolic acid, thiodiglycolic acid, poly(ethylene glycol)bis(carboxymethyl) ether, a hydrogenated dimer acid or an acid chloride thereof. Suitably, the or each polycarboxylic acid or the reactive equivalent thereof may be selected from oxalic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, malic acid, tartaric acid, citric acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, diglycolic acid, thiodiglycolic acid, poly(ethylene glycol)bis(carboxymethyl) ether, a hydrogenated dimer acid, or an acid chloride thereof. Preferably, the or each polycarboxylic acid or the reactive equivalent thereof may be selected from succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, malic acid, tartaric acid, citric acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, diglycolic acid, thiodiglycolic acid, poly(ethylene glycol)bis(carboxymethyl) ether, a hydrogenated dimer acid, oxalyl chloride, isophthaloyl chloride, or terephthaloyl chloride. Citric acid and diglycolic acid may be preferred polycarboxylic acids. One or more of the second monomers may be a monocarboxylic acid or ester thereof. Suitable monocarboxylic acids may be aliphatic or aromatic. The aliphatic monocarboxylic acid may be cycloaliphatic. The aliphatic monocarboxylic acid may be saturated or unsaturated. The monocarboxylic acid may contain from 2 to 40 carbon atoms, suitably from 4 to 30 carbon atoms, preferably from 6 to 20 carbon atoms, for example from 8 to 18 carbon atoms. The monocarboxylic acid may be a fatty acid. Examples of suitable monocarboxylic acids or esters thereof include hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolelaidic acid, arachidic acid, arachidonic acid, behenic acid, erucic acid, and esters (preferably methyl esters) thereof. Preferably, the monocarboxylic acid is selected from propionic acid, hexanoic acid, lauric acid, stearic acid, oleic acid, or erucic acid. One or more of the second monomers may be an epoxide compound. Suitable epoxide compounds may comprise one or more than one epoxide group. For example, suitable epoxide compounds may comprise two epoxide groups. Preferred epoxide compounds comprise a single (i.e. only one) epoxide group. Examples of suitable epoxide compounds include 1,2-epoxydodecane, ethyl glycidyl ether, isopropyIglycidyI ether, 2-ethylhexyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, butyl glycidyl ether (such as n-butyl glycidyl ether), 1,2-epoxyhexane, epichlorohydrin, glycidyltrimethylammonium chloride, cyclopentene oxide, cyclohexene oxide, poly(ethylene glycol) diglycidyl ether, poly(propylene glycol) diglycidyl ether and poly(butylene glycol) diglycidyl ether. One or more of the second monomers may be a polyfunctional monomer having a reactive amino group. By the term “polyfunctional monomer” we mean a monomer with at least two reactive groups. By the term “reactive group” we mean a group that reacts with the first monomer and / or the second monomer. At least one of the reactive groups is a reactive amino group. The other reactive groups in the polyfunctional monomer may be reactive amino groups, or may be reactive groups other than amino groups, such as hydroxy groups or carboxyl groups. Reactive amino groups are suitably primary amino groups or secondary amino groups. The polyfunctional monomer may comprise at least one reactive amino group and at least one hydroxy group. The polyfunctional monomer may be an alkanolamine or an alkoxylated alkanolamine. The polyfunctional monomer may comprise at least two reactive amino groups. The polyfunctional monomer may be an aliphatic diamine, a polyether diamine, or a polyalkylene polyamine. The polyfunctional monomer may comprise at least one reactive amino group and at least one carboxyl group. The polyfunctional monomer may be an amino acid, such as a naturally occurring amino acid. Examples of suitable polyfunctional monomers having at least one reactive amino group include ethanolamine, diethanolamine, ethylene diamine, coco propylene diamine, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), a polyether diamine (preferably Jeffamine ED-600, Jeffamine ED-900, or Jeffamine ED-2003 which are commercially available), alanine, arginine, asparagine, aspartate, cysteine, glutamine, glutamate, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. One or more of the second monomers may be a monoalcohol. Suitable monoalcohols may be aliphatic or aromatic. The aliphatic monoalcohol may be cycloaliphatic. The aliphatic monoalcohol may be saturated or unsaturated. The monoalcohol may contain from 2 to 40 carbon atoms, suitably from 4 to 30 carbon atoms, preferably from 6 to 20 carbon atoms, for example from 8 to 18 carbon atoms. The monoalcohol may be a fatty alcohol. Examples of suitable monoalcohols include hexanol, octanol, 2-ethylhexanol, decanol, dodecanol alcohol, myristyl alcohol, myristoleyl alcohol, palmityl alcohol, palmitoleyl alcohol, stearyl alcohol, oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolelaidyl alcohol, arachidyl alcohol, arachidonyl alcohol, behenyl alcohol, erucyl alcohol, benzyl alcohol, glycerol carbonate and choline chloride. Preferably, the monoalcohol is glycerol carbonate, hexanol or oleyl alcohol. Preferably, the monoalcohol is hexanol or oleyl alcohol. Glycerol carbonate is a preferred monoalcohol. One or more of the second monomers may be a monofunctional monomer having a reactive amino group. Suitable monofunctional monomers having a reactive amino group have one reactive amino group and no other reactive groups. The monofunctional monomer may contain other functional groups that are not reactive groups, such as tertiary amino groups or ether groups. The monofunctional monomer may be an aliphatic monoamine (such as a fatty alkyl amine), an N,N-dialkylaminoalkylamine, or a polyether monoamine. The polyether monoamine suitably comprises a polyether backbone selected from polyethylene glycol (PEG), polypropylene glycol (PPG), or a copolymer of polyethylene glycol (PEG) and polypropylene glycol (PPG). The copolymer of PEG and PPG may be a block copolymer or a random copolymer. The polyether backbone is suitably capped at one end with the reactive amino group, and capped at the other end with an alkyl group (preferably a methyl group). The polyether monoamine suitably has a molecular weight of from 150 to 6000, preferably from 400 to 3000, for example from 600 to 2000. The polyether monoamine may have a weight average molecular weight of from 150 to 6000, preferably from 400 to 3000, for example from 600 to 2000. Examples of suitable monofunctional monomers having a reactive amino group include propylamine, dipropylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, tallow alkyl amine, benzylamine, phenethylamine, 3-dimethylaminopropylamine (DMAPA), or Jeffamine M-1000 (which is commercially available). Preferably, the monofunctional monomer having a reactive amino group is selected from dodecylamine, N,N-dimethylaminopropylamine (DMAPA), or Jeffamine M-1000. In one embodiment, the polymer may be the reaction product of monomers comprising one (i.e. a single) hydroxycarboxylic acid or a cyclic ester thereof and one (i.e. a single) monomer (i) to (viii) as defined herein. In other embodiments, the polymer may be the reaction product of monomers comprising two different hydroxycarboxylic acids or cyclic esters thereof and one (i.e. a single) monomer (i) to (viii) as defined herein, or the polymer may be the reaction product of monomers comprising one (i.e. a single) hydroxycarboxylic acid or a cyclic ester thereof and two different monomers (i) to (viii) as defined herein. The combined amount of the one or more first monomers and the one or more second monomers (when present) may be at least 50 mol%, suitably at least 75 mol%, preferably at least 90 mol%, for example at least 95 wt% of the monomers that are reacted to obtain the polymer. In one embodiment, the polymer may be the reaction product of monomers consisting essentially of or consisting of one (i.e. a single) hydroxycarboxylic acid or a cyclic ester thereof and one (i.e. a single) monomer (i) to (viii) as defined herein. In other embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of two different hydroxycarboxylic acids or cyclic esters thereof and one (i.e. a single) monomer (i) to (viii) as defined herein, or the polymer may be the reaction product of monomers consisting essentially of or consisting of one (i.e. a single) hydroxycarboxylic acid or a cyclic ester thereof and two different monomers (i) to (viii) as defined herein. The polymer for use herein may be the reaction product of monomers comprising the one or more first monomers and optionally one or more second monomers as disclosed herein. In other words, the polymer may be the reaction product of monomers comprising one or more first monomers as disclosed herein and optionally one or more second monomers as disclosed herein. The polymer for use herein may be the reaction product of monomers consisting essentially of or consisting of the one or more first monomers and optionally one or more second monomers as disclosed herein. In other words, the polymer may be the reaction product of monomers consisting essentially of or consisting one or more first monomers as disclosed herein and optionally one or more second monomers as disclosed herein. The polymer for use herein is suitably the reaction product of no more than four different monomers. Preferably, the polymer is the reaction product of no more than three different monomers. For example, the polymer may be the reaction product of one first monomer and one or two second monomers, or the reaction product of two different first monomers and one second monomer as disclosed herein. In some preferred embodiments, the polymer is the reaction product of only two different monomers, for example the reaction product of two first monomers or the reaction product of one first monomer and one second monomer as disclosed herein (and no further monomers). The polymers may be prepared from the first and optionally second monomers by any suitable method, as would be known to the person skilled in the art. The polymerisation reaction will typically be conducted in the presence of a suitable polymerisation catalyst, such as tin(ll) ethylhexanoate, tin(ll) oxalate, p-toluenesulfonic acid, methanesulfonic acid, or sulfuric acid. The polymerisation reaction may be carried out for any suitable length of time, such as at least 1 hour, preferably at least 3 hours, for example at least 5 hours. The polymerisation reaction may be carried out at any suitable temperature, such as from 50 to 300°C, preferably from 100 to 200°C Suitable molar ratios of the first and, when present, second monomers may be used to prepare the polymers. Thus repeat units in the polymer derived from the first and, when present, second monomers when present may be present in the polymer in any suitable molar ratio and in any suitable arrangement. Suitably, the polymer is not further reacted after the reaction of the monomers. Suitably the polymer may be the reaction product of monomers comprising one or more first monomers and no second monomers as defined herein. Suitably the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers as defined herein. Suitably when the polymer is the reaction product of monomers comprising one or more first monomers and one or more second monomers as defined herein, the polymer is a random copolymer. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid ora reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more cyclic anhydride. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers, wherein the or each first monomer is selected from one or more (for example one or two) of a hydroxycarboxylic acid or a cyclic ester thereof. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid ora reactive equivalent thereof, a monoalcohol and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid ora reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein, and wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein, and wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer (when present) is selected from one or more cyclic anhydride, wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more cyclic anhydride, wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more cyclic anhydride. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein, and wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein, and wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol, wherein the or each hydroxycarboxylic acid is of the formula R(CR2)nCOOH wherein n and R are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer (when present) is selected from one or more cyclic anhydride, wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more cyclic esters of a hydroxycarboxylic acid, and wherein the or each second monomer is selected from one or more cyclic anhydride, wherein the or each cyclic ester is of the formula (I) or (II) wherein R1, R2, n2, R3, R4, n3 and n4 are as defined herein. Suitably the or each second monomer may be selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably the or each second monomer may be selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol. Suitably the or each second monomer may be selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, when the or each second monomer is a polyol, the second monomer may be selected from ethylene glycol, trimethylol propane, 1,6-hexanediol and a polyalkylene glycol (such as polyethylene or polypropylene glycol, for example polypropylene glycol such as PPG 2000). More suitably, when the or each second monomer is a polyol, the second monomer may be selected from 1,6-hexanediol and a polyalkylene glycol (such as polyethylene or polypropylene glycol, for example polypropylene glycol such as PPG 2000). Suitably, when the or each second monomer is a cyclic anhydride, the second monomer may be (2-dodecen-1-yl)succinic anhydride. Suitably, when the or each second monomer is a polycarboxylic acid or a reactive equivalent thereof, the second monomer may be diglycolic acid. Suitably, when the or each second monomer is a monoalcohol, the second monomer may be glycerol carbonate. Suitably, the or each second monomer (when present) may be selected from 1,6-hexanediol, a polyalkylene glycol (such as PPG 2000), (2-dodecen-1-yl)succinic anhydride and diglycolic acid. When the second monomer is selected from one or more polycarboxylic acid(s) or reactive equivalent(s) thereof and one or more polyol(s), the molar ratio of the sum of the polycarboxylic acid(s) or reactive equivalent(s) thereof and the sum of the polyol(s) may be about 1:1. Suitably, the or each first monomer may be selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid, 12-hydroxystearic acid and s-caprolactone. Preferably, the or each first monomer may be selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone. Preferably, the or each first monomer may be selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and 12-hydroxystearic acid. More preferably, the or each first monomer may be selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid and malic acid. Even more preferably, the or each first monomer may be selected from one or more of ricinoleic acid, glycolic acid and citric acid. Suitably, at least one of the first monomers is 12-hydroxystearic acid. Suitably, at least one of the first monomers is ricinoleic acid, DL-lactide or £-caprolactone. Suitably, at least one of the first monomers is ricinoleic acid. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid ora reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a cyclic anhydride, a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a cyclic anhydride, a polycarboxylic acid ora reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid ora reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and wherein the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of DL-lactide and s-caprolactone, and wherein the or each second monomer (when present) is selected from one or more cyclic anhydride. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of DL-lactide and s-caprolactone, and wherein the or each second monomer is selected from one or more cyclic anhydride. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of DL-lactide and s-caprolactone, and wherein the or each second monomer (when present) is selected from one or more cyclic anhydride. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the or each first monomer is selected from one or more of DL-lactide and s-caprolactone, and wherein the or each second monomer is selected from one or more cyclic anhydride. In some embodiments, the polymer may be the reaction product of monomers comprising ricinoleic acid and one or more additional first monomers, for example one or more additional first monomers selected from glycolic acid, citric acid and malic acid (especially glycolic acid and citric acid), suitably in a molar ratio of from 1:1 to 1:2, and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers comprising ricinoleic acid and one or more additional first monomers, for example one or more additional first monomers selected from glycolic acid, citric acid and malic acid (especially glycolic acid and citric acid, suitably in a molar ratio of from 1:1 to 1:2, and one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers comprising two or more first monomers, for example selected from two or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, glycolic acid and citric acid), and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers comprising two or more first monomers, for example selected from two or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, glycolic acid and citric acid, and one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers comprising DL-lactide and s-caprolactone as the first monomers, and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers comprising DL-lactide and s-caprolactone as the first monomers, and one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of ricinoleic acid and one or more additional first monomers, for example one or more additional first monomers selected from glycolic acid, citric acid and malic acid (especially glycolic acid and citric acid), suitably in a molar ratio of from 1:1 to 1:2, and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of ricinoleic acid and one or more additional first monomers, for example one or more additional first monomers selected from glycolic acid, citric acid and malic acid (especially glycolic acid and citric acid), suitably in a molar ratio of from 1:1 to 1:2, and one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of two or more first monomers, for example selected from two or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, glycolic acid and citric acid), and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of two or more first monomers, for example selected from two or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and £-caprolactone (especially ricinoleic acid, glycolic acid and citric acid), and one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of DL-lactide and s-caprolactone as the first monomers, and optionally one or more second monomers. In some embodiments, the polymer may be the reaction product of monomers consisting essentially of or consisting of DL-lactide and s-caprolactone as the first monomers, and one or more second monomers. Suitably, when a second monomer is present, the molar ratio of total of the first monomers to the total of the second monomers may be from 8:1 to 1:1, such as from 8:2 to 7:3. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, glycolic acid and citric acid); wherein the one or more second monomers (when present) are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and (2-dodecen-1-yl) succinic anhydride. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, glycolic acid and citric acid); wherein the one or more second monomers are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and (2-dodecen-1-yl) succinic anhydride. Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid); wherein the one or more second monomers (when present) are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and glycerol carbonate (especially 1,6-hexanediol and diglycolic acid). Suitably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid); wherein the one or more second monomers are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and glycerol carbonate (especially 1,6-hexanediol and diglycolic acid). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, glycolic acid and citric acid); wherein the one or more second monomers (when present) are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and (2-dodecen-1-yl) succinic anhydride. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, glycolic acid and citric acid); wherein the one or more second monomers are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and (2-dodecen-1-yl) succinic anhydride. Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and optionally one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid); wherein the one or more second monomers (when present) are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and glycerol carbonate (especially 1,6-hexanediol and diglycolic acid). Suitably, the polymer may be the reaction product of monomers consisting essentially of or consisting of one or more first monomers and one or more second monomers, wherein the one or more first monomers are selected from one or more of ricinoleic acid, DL-lactide, glycolic acid, citric acid, malic acid and s-caprolactone (especially ricinoleic acid, citric acid and glycolic acid); wherein the one or more second monomers are selected from one or more of 1,6-hexanediol, PPG 2000, diglycolic acid and glycerol carbonate (especially 1,6-hexanediol and diglycolic acid). Preferably, the polymer is the reaction product of monomers comprising: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075; (vii) DL-lactide, s-caprolactone and (2-dodecen-1-yl)succinic anhydride, preferably in a molar ratio of 1:1:0.01; or (viii) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.6:0.1:0.2:0.1. Preferably, the polymer is the reaction product of monomers comprising: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075; or (vii) DL-lactide, s-caprolactone and (2-dodecen-1-yl)succinic anhydride, preferably in a molar ratio of 1:1:0.01. Preferably, the polymer is the reaction product of monomers consisting essentially of or consisting of: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075; (vii) DL-lactide, s-caprolactone and (2-dodecen-1-yl)succinic anhydride, preferably in a molar ratio of 1:1:0.01; or (viii) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.6:0.1:0.2:0.1. Preferably, the polymer is the reaction product of monomers consisting essentially of or consisting of: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075; or (vii) DL-lactide, s-caprolactone and (2-dodecen-1-yl)succinic anhydride, preferably in a molar ratio of 1:1:0.01. More preferably, the polymer is the reaction product of monomers comprising: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; or (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075. More preferably, the polymer is the reaction product of monomers consisting essentially of or consisting of: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:2; (iii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; (iv) ricinoleic acid and malic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.8:0.05:0.1:0.05; or (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.7:0.075:0.15:0.075. Preferably, the polymer is the reaction product of monomers comprising: (i) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (ii) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; or (iii) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.6:0.1:0.2:0.1. Preferably, the polymer is the reaction product of monomers consisting essentially of or consisting of: (iv) ricinoleic acid and glycolic acid, preferably in a molar ratio of 1:1; (v) ricinoleic acid and citric acid, preferably in a molar ratio of 1:1; or (vi) ricinoleic acid, 1,6-hexanediol, diglycolic acid and PPG 2000, preferably in a molar ratio of 0.6:0.1:0.2:0.1. Preferably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof selected from one or more of glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, and DL-lactide. Preferably, the polymer may be the reaction product of monomers comprising one or more first monomers, wherein the polymer is a homopolymer and the first monomer is a hydroxycarboxylic acid orthe cyclic ester thereof selected from one of glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, and DL-lactide. Preferably, the polymer may be the reaction product of monomers comprising one or more first monomers, wherein the polymer is a homopolymer and the first monomer is a hydroxycarboxylic acid orthe cyclic ester thereof selected from one of hydroxystearic acid and ricinoleic acid. Preferably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the polymer is a copolymer and the or each first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from two or more of DL-lactide, citric acid ors-caprolactone; orthe each first monomer is a hydroxycarboxylic acid orthe cyclic ester thereof selected from two or more of ricinoleic acid, glycolic acid, mandelic acid, malic acid, and citric acid (especially ricinoleic acid, citric acid and glycolic acid). Preferably, the polymer may be the reaction product of monomers comprising one or more first monomers and one or more second monomers, wherein the polymer is a copolymer and the or each first monomer is a hydroxycarboxylic acid orthe cyclic ester thereof selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid (especially ricinoleic acid, citric acid and glycolic acid), and the or each second monomer is selected from one or more of a polycarboxylic acid ora reactive equivalent thereof and a polyol. The polymer formed from the first and optional second monomers may comprise a suitable number of total monomer units (i.e. repeat units). For example, the polymer may comprise at least 4 monomer units. In other words, the polymer may comprise a total of at least 4 monomer units including the first and optional second monomers. Suitably, the polymer may comprise from 4 to 50 monomer units, preferably from 4 to 30 monomer units. Suitably, the polymer has a number average molecular weight of from 1,000 to 50,000 Daltons, preferably from 1,000 to 15,000 Daltons (for example from 2,000 to 7,000 Daltons). Preferably, the polymer is substantially free of silicon atoms. By substantially free of silicon atoms we mean that the polymer contains less than 1 wt% of silicon in the polymer, preferably less than 0.5 wt% of silicon in the polymer. More preferably, the polymer is free of silicon atoms, by which we mean that it is not possible to detect silicon in the polymer. Suitable methods of measuring the amount of silicon in a polymer are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. Preferably, the polymer is substantially free of fluorine atoms. The polymer may be substantially free of halogen atoms. By substantially free of fluorine or halogen atoms we mean that the polymer contains less than 1 wt% of fluorine or halogen in the polymer, preferably less than 0.5 wt% of fluorine or halogen in the polymer. More preferably, the polymer is free of fluorine atoms. The polymer may be free of halogen atoms. By free of fluorine or halogen atoms we mean that it is not possible to detect fluorine or halogen in the polymer. Suitable methods of measuring the amount of fluorine or halogen in a polymer are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. Preferably, the polymer is substantially free of quaternary ammonium moieties. By substantially free of quaternary ammonium moieties we mean that the polymer contains less than 1 wt% of quaternary nitrogen atoms in the polymer, preferably less than 0.5 wt% of quaternary nitrogen atoms in the polymer. More preferably, the polymer is free of quaternary ammonium moieties, by which we mean that it is not possible to detect quaternary ammonium moieties in the polymer. The use of the polymer according to the first aspect is to treat a surface to provide at least one effect (i.e. to the substrate) selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance. The method according to the second aspect treats a surface to provide at least one effect (i.e. to the substrate) selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance. The use of the first aspect and method of the second aspect is to treat a surface. The surface is any surface that is not a surface of a home care substrate. The surface may be a surface of any suitable substrate, provided that it is not a home care substrate. References herein to treating and contacting a surface are intended to refer to treating or contacting the entire surface or a portion thereof. References to herein to (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance of a surface are intended to mean as compared to an otherwise identical surface that has not been treated with the polymer or composition as disclosed herein. The use of the first aspect and the method of the second aspect treat a surface, wherein treating the surface provides at least one effect selected from: (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance. Treating the surface may provide at least one effect selected from: (a) increased water repellency, and (b) reduced friction. Treating the surface may provide: (a) increased water repellency, and (b) reduced friction. Treating the surface may provide at least two effects selected from: (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance. Treating the surface may provide: (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance. Treating the surface may provide (a) increased water repellency, i.e. to the surface. A surface with increased water repellency may have decreased water wettability. Wettability can be determined by measuring the contact angle between a liquid droplet and a solid surface, and a decrease in wettability may be demonstrated by measuring a greater contact angle following treatment of the surface with the polymer defined herein. Methods and equipment for the measurement of contact angle are well known to the skilled person. An example is ISO / TS 14778:2021 which is concerned with the measurement of contact angle on paper and board substrates. Water is less likely to adhere to water repellent surfaces, and water droplets may simply roll off the surface. In doing so, water droplets may carry undesirable particles, such as foulants, pollution, food waste, oils, dust or dirt away from the surface. Treating the surface may therefore provide an enhanced cleaning effect or self-cleaning effect, and / or increased resistance to undesirable particles such as foulants, pollution, food waste, oils, dust or dirt. Treating the surface may repel undesirable particles, such as foulants, pollution, food waste, oils, dust or dirt, and / or may prevent deep soiling. By repel undesirable particles we mean that treating the surface may reduce or prevent deposition of the undesirable particles on the surface. A surface with increased water repellency may dry more quickly. A surface with increased water repellency may substantially or completely prevent water from penetrating the surface, providing long-lasting protection against moisture, stains, and potential water damage. Methods and equipment for the measurement of water repellency are well known to the skilled person. An example is the test procedure TM22-2017e which may be used to measure the water repellency of a fabric. The water repellency of the surface of a substrate may be measured by weighing the substrate, immersing the substrate in water (for example, for 5 minutes), removing the substrate from the water and allowing excess water to drain off (for example, for 1 minute), then weighing the substrate again. The weight of the water in the substrate compared to the weight of the dry substrate (i.e. before immersion in water) corresponds to the water uptake of the substrate. A lower water uptake (i.e. relative to a control experiment in which the polymer is absent) corresponds to increased water repellency. A surface with increased water repellency may be especially useful for applications where surfaces require cleaning. For example, it is advantageous to provide a surface with increased water repellency, such that the surface may be readily and / or more effectively cleaned. Treating the surface may provide (b) reduced friction, i.e. to the surface. By providing reduced friction we mean that the surface has an increased smoothness and / or a reduced resistive force or coefficient of friction when an object is slid over the surface. A surface with reduced friction may be useful for applications where surfaces move against one another. Thus, when the effect is to provide reduced friction, this may advantageously provide improved lubrication. Thus, the use of the first aspect and the method of the second aspect may provide improved lubrication of a surface thereof. The use of the first aspect may therefore provide the use of a polymer as defined herein as a lubricant for a surface. The method of the second aspect may provide a method of lubricating a surface, the method comprising contacting the surface with a polymer as defined herein. The use of the first aspect may be the use of the polymer as defined herein as a lubricating agent. Friction between two surfaces may be determined by sliding the surfaces against one another and measuring the resistive force or coefficient of friction. The coefficient of friction of plastic films may be measured by the test procedure ASTM D1894. A surface with reduced friction may reduce the build up of static on the surface. Thus, treating the surface may provide (b) reduced friction and thereby provide an antistatic effect. A surface with an antistatic effect may advantageously reduce the buildup of dust and reduce electric discharges when the surface contacts another surface. Treating the surface may provide (c) improved visual appearance, i.e. to the surface. For example, improved visual appearance may provide increased shine. By “shine” we mean the perceived reflectiveness of a surface. As used herein, shine, gloss and reflectiveness are considered interchangeable. A surface with increased shine may be desirable from an aesthetic standpoint. Increased shine can also be a visual indicator of the surface having other properties provided by treatment with the polymer as defined herein, such as increased water repellency and / or reduced friction. When the shine of the surface decreases, this can be used to prompt a user to retreat the surface with the polymer. The gloss or shine of surfaces can be measured by reflectance methods, for example DIN 67530. A surface with improved visual appearance (such as increased shine) may be useful for applications where surfaces are required to look appealing visually. The use of the first aspect and the method of the second aspect suitably involve coating at least a portion of the surface with the polymer as defined herein. The polymer may be coated onto the surface by spreading, such as by a blade, brush, cloth or sponge. The polymer may be applied onto the surface by spraying, for example from a pressurised can. The polymer may be applied to the surface as a foam, for example by spraying the polymer through a foam-forming nozzle. The use of the first aspect and the method of the second aspect may involve distributing the polymer as defined herein in the substrate. When the substrate is a solid substrate, the solid substrate may be formed from a liquid precursor (such as a melt) into which the polymer is admixed. Typically, the polymer will migrate to the surface of the liquid precursor and thereby the surface of the solid substrate. For example, the polymer may be admixed into an extruded product prior to extrusion. The use and method according to the first and second aspects may treat any suitable surface that is not a surface of a home care substrate and that would benefit from one or more of (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance (especially (a) increased water repellency and (b) reduced friction). The surface is not a surface of a home care substrate. In other words, the surfaces that are referred to in this specification are non-home care surfaces. By a home care substrate we mean any substrate of the home or household contents. Home care substrate preferably includes a fabric or a hard surface. “Fabric” includes clothing, linens and other household textiles, such as upholstery, curtains, blinds etc. In the context of fabrics, the term “linen” is used to describe certain types of laundry items including bed sheets and bed covers, pillow cases, towels, tablecloths, table napkins, uniforms and the like, but also washable household items such as curtains and blinds, washable upholstery items such as cushion covers and the like. The term “ household textiles” can include woven fabrics, non-woven fabrics, and knitted fabrics and fabrics can include natural or synthetic fibres such as silk fibres, linen fibres, cotton fibres, polyester fibres, polyamide fibres such as nylon, rayon, acrylic fibres, acetate fibres, and blends thereof including cotton and polyester blends, fabrics which are elastic and / or contain elastane, and also viscose, modal and lyocell. “Hard surface” includes surfaces of dishes and other household surfaces. “Dishes” is meant generically and encompasses essentially any items which may be found in a dishwashing (manual or automatic machine) load, including crockery, chinaware, glassware, plasticware, siliconeware, silverware, hollowware and cutlery and any of these may comprise a hard surface; and “household surface” means any surface found in and around houses as in kitchens, bathrooms, e.g., floors, walls, tiles, windows, cupboards, sinks, showers, shower plastified curtains, wash basins, WCs, fixtures and fittings, and furniture. Hard surfaces may be made of different materials like ceramic, vinyl, no-wax vinyl, linoleum, melamine, glass, Inox®, Formica®, vitroceramic, any plastics, plastified wood, metal or any painted or varnished or sealed surface and the like; as well as household appliances including, but not limited to refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens, dishwashers and so on. The surface is suitably an industrial surface. By industrial surface we mean any surface in an industrial setting and scale. The industrial surface may undergo a treatment as defined herein during an industrial process, such as an industrial process of the manufacturing industry, the packaging industry, construction industry, the automotive industry, the aviation industry, the agricultural industry, or the mining industry. An industrial process does not, for example, include a consumer-related activity. Thus, the industrial surface is found in an industrial setting not, for example, the home. The industrial surface may be a surface of an industrial product. By an industrial product we mean a product in an industrial setting and scale, which may undergo a treatment as defined herein during an industrial process. The industrial surface may be a surface of industrial equipment. By industrial equipment we mean equipment that is used in an industrial setting and scale, for example that is used in large scale manufacturing, storage, extraction, processing, treatment and / or transportation. Examples of industrial equipment will be well known to persons skilled in the art and include machinery and engines (including components thereof). The industrial surface may treated by an industrial process in the manufacturing industry. For example, the industrial surface may be the surface of a product of the manufacturing industry or the surface of equipment used in the manufacturing industry. The industrial surface may be treated by an industrial process in the packaging industry. For example, the industrial surface may be the surface of a product of the packaging industry or the surface of equipment used in the packaging industry. The industrial surface may be treated by an industrial process in the construction industry. For example, the industrial surface may be the surface of a product of the construction industry or the surface of equipment used in the construction industry. The industrial surface may be treated by an industrial process in the automotive industry. For example, the industrial surface may be the surface of a product of the automotive industry or the surface of equipment used in the automotive industry. The industrial surface may be treated by an industrial process in the aviation industry. For example, the industrial surface may be the surface of a product of the aviation industry or the surface of equipment used in the aviation industry. The industrial surface may be treated by an industrial process in the agricultural industry. For example, the industrial surface may be the surface of a product of the agricultural industry or the surface of equipment used in the agricultural industry. The industrial surface may be treated by an industrial process in the mining industry. For example, the industrial surface may be the surface of a product of the mining industry or the surface of equipment used in the mining industry. The surface is suitably a solid surface. The solid surface may be a hard surface or a soft surface. The surface may be formed from any suitable material such as one or more materials selected from metal, glass, ceramic, glass-ceramic, stone, concrete, gypsum, stucco, plastic, rubber, wood, paper-based materials (such as paper or cardboard) and leather (including combinations thereof, such as a laminate for example). Examples of suitable surfaces include the surfaces of extruded products (such as pellets, granules, or films), moulds, non-household buildings (such as walls, windows, floors, or ceilings), paper-based packaging, construction materials (such as plasterboard, gypsum, stucco, or concrete), vehicles (such as windows, tyres, vehicle bodies, or vehicle interiors), plants (such as seeds), solid agrochemical compositions, and non-household fibrous substrates. The surface may be selected from the surface of an extruded product (such as a pellet, granule, or film), a mould, paper packaging, a construction material (such as plasterboard, gypsum, stucco, or concrete), a vehicle (such as a window, tyre, vehicle body, or vehicle interior), a plant (such as a seed), a solid agrochemical composition, or a non-household fibrous substrate. The surface may be selected from the surface of an extruded product (such as a pellet, granule, or film), a mould, paper packaging, a construction material (such as plasterboard, gypsum, stucco, or concrete), a plant (such as a seed), or a solid agrochemical composition. The use of the first aspect and the method of the second aspect may provide a surface of an extruded product or a precursor thereof with reduced friction. The extruded product or the precursor thereof may be treated with the polymer defined herein during manufacture of the extruded product. By “precursor” of the extruded product, we mean the extruded product prior to extrusion. Suitably, the precursor of the extruded product is treated with the polymer defined herein prior to extrusion of the precursor. The reduced friction of the surface of the precursor may facilitate the extrusion process, for example by providing better handling and better cleaning due to reduced residue on the extrusion equipment. The extruded product may be a pellet, a granule, or a film. The extruded product may be a plastic film. The plastic film may form part of, or be suitable for manufacturing, plastic bags or packaging. The surface of the plastic film may be treated with the polymer defined herein during manufacture of the plastic film, and / or manufacture of plastic bags or packaging from the plastic film. By “manufacture of packaging” we mean to refer to the formation of the components of the packaging or the assembly of the packaging. The reduced friction of the surface of the plastic film reduces friction between the surface of the plastic film and other surfaces of the plastic film, between the surface of the plastic film and surfaces of other plastic films, and / or between the surface of the plastic film and manufacturing equipment. This may advantageously improve the movement of the plastic film through a manufacturing line (for example an extrusion line) or a packaging line, by causing the plastic film to slide more easily. The use of the first aspect may be the use of the polymer as defined herein as a slip additive. The plastic film may comprise any suitable polymeric material, such as polyethylene or polypropylene. The polyethylene may be selected from very low density polyethylene, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, or ultra-high molecular weight polyethylene. Preferably, the polymeric material is prepared from vinyl monomers, especially alpha olefins such as ethylene or propylene. The use of the first aspect and the method of the second aspect may provide a surface of a mould with reduced friction. The mould may be for the manufacture of moulded objects. An internal surface of the mould (preferably, a surface that will be in contact with a moulded object) is treated with the polymer defined herein. The reduced friction of the surface of the mould may advantageously prevent sticking of a moulded object in the mould and facilitate removal of the moulded object from the mould. The use of the first aspect and the method of the second aspect may provide a surface of a nonhousehold building with increased water repellency, reduced friction, and / or improved visual appearance. By non-household building we mean a building that is not a home. Examples of suitable non-household buildings include commercial buildings (such as offices, shops, restaurants, and hotels), institutional buildings (such as schools and hospitals), and industrial buildings (such as factories and warehouses). The surface may be an exterior surface or an interior surface of the building. The surface of the building may be selected from a surface of a wall, a window, a floor, or a ceiling. The use of the first aspect and the method of the second aspect may provide a surface of a wall, floor, or ceiling of a non-household building with increased water repellency, reduced friction, and / or improved visual appearance. Increasing the water repellency and / or reducing the friction of the surface of the wall, floor, or ceiling may prevent dust or dirt from adhering to the surface, facilitate cleaning of the surface, and / or reduce the formation of streaks on the surface. When the wall, floor, or ceiling is painted, the colour intensity of wall, floor, or ceiling may be increased. When the wall, floor, or ceiling is treated with the polymer as disclosed herein, paint may be more easily and / or evenly applied to the treated wall, floor or ceiling. The use of the first aspect and the method of the second aspect may provide a surface of a window of a non-household building with increased water repellency and / or reduced friction. Increasing the water repellency and / or reducing the friction of the surface of the window may prevent dust or dirt from adhering to the window, facilitate cleaning of the window, shorten drying times, reduce the formation of streaks on the window, provide the window with an anti-fingerprint effect, and / or provide the window with an antifogging effect. The use of the first aspect and the method of the second aspect may provide a surface of a paper-based material with increased water repellency. Examples suitable of paper-based materials include paper and cardboard. Paper-based materials are typically vulnerable to damage from exposure to water or moisture. Therefore, increasing the water repellency of a surface of a paper-based material may advantageously increase the lifetime of the underlying paper-based material. The surface of the paper-based material may be the surface of paperbased packaging (for example packaging comprising paper or cardboard). The use of the first aspect and the method of the second aspect may provide a surface of a construction material with increased water repellency. The construction material may be plasterboard, gypsum, stucco, or concrete. The construction material is preferably plasterboard, gypsum, or stucco, further preferably plasterboard or gypsum. Plasterboard is typically a panel of gypsum between two sheets of paper, and may be prepared by feeding a foamed slurry of stucco (calcined gypsum) and water between two sheets of paper. Both paper and gypsum are typically vulnerable to damage from exposure to water (including recycled water) or moisture. Therefore, increasing the water repellency of the paper sheets and / or the gypsum in plasterboard may increase the lifespan of the plasterboard and allow the use of recycled water. The polymer as defined herein may be coated on a surface of plasterboard or gypsum. Alternatively, the polymer may be admixed into a slurry of stucco and water as an additive during the production of plasterboard or gypsum. For example, the method of the second aspect may comprise admixing the polymer into a slurry comprising water and stucco or gypsum. The method may further comprise drying the slurry to form gypsum. The polymer may be present in the bulk of the gypsum and / or at the surface of the gypsum produced in this way. The polymer is suitably present at the surface of the gypsum. The method may provide a construction material (and not just a surface thereof) with increased water repellency. The use of the first aspect and the method of the second aspect may provide a surface of a vehicle with increased water repellency, reduced friction, and / or improved visual appearance. The surface may be an exterior surface or an interior surface of the vehicle. The vehicle may be selected from a road vehicle, a water vehicle, or an air vehicle. Preferably the vehicle is a road vehicle, such as a car. The surface of the vehicle may be selected from a surface of a window, a tyre, a vehicle body, or a vehicle interior. The use of the first aspect and the method of the second aspect may provide a surface of a vehicle window with increased water repellency and / or reduced friction. Increasing the water repellency and / or reducing the friction of the surface of the window may prevent dust or dirt from adhering to the window, facilitate cleaning of the window, shorten drying times, reduce the formation of streaks on the window, provide the window with an anti-fingerprint effect, and / or provide the window with an antifogging effect. The use of the first aspect and the method of the second aspect may provide a surface of a tyre with increased water repellency and / or improved visual appearance. The tyre is suitably the tyre of a road vehicle such as a car. Increasing the water repellency and / or shine of the surface of the tyre may improve the appearance of the tyre, increase the durability of the tyre, reduce build up of undesirable particles (such as dirt) on the tyre, and / or reduce degradation of other components of the vehicle, such as wear brakes. The use of the first aspect and the method of the second aspect may provide a surface of a vehicle body with increased water repellency, reduced friction, and / or improved visual appearance. The surface of the vehicle body is suitably an exterior surface of the vehicle body. The vehicle body suitably comprises coated metal. The vehicle body may be a car body. Increasing the water repellency and / or reducing the friction of the surface of the vehicle body may prevent dust or dirt from adhering to the body, facilitate cleaning of the body, shorten drying times, reduce the formation of streaks on the body, facilitate water sheeting and beading, and / or provide the body with rain resistance. The use of the first aspect and the method of the second aspect may provide a surface of a vehicle interior with increased water repellency, reduced friction, improved visual appearance, and / or an antistatic effect. The vehicle interior may be interior plastic trim or leather. Increasing the water repellency and / or reducing the friction of the surface of the vehicle interior may improve the dirt resistance and facilitate cleaning of the surface. Reducing the friction of a leather surface in the vehicle interior may increase the softness thereof. The use of the first aspect and the method of the second aspect may provide leather (or a surface thereof) with increased softness and / or flexibility. This may be the result of reduced friction. The use of the first aspect and the method of the second aspect may provide a surface of a seed with increased water repellency and / or reduced friction. By “seed” we mean a plant seed. Increasing the water repellency of the surface of a seed may increase the length of time the seed may be stored before planting. Reducing the friction of the surface of a seed may improve the flow characteristics of the seed during plantation, in particular when a plurality of such seeds are being planted. The polymer used to treat the surface of the seed is preferably the reaction product of monomers comprising, consisting essentially of, or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid or a reactive equivalent thereof and a polyol). The use of the first aspect and the method of the second aspect may provide a surface of a solid agrochemical composition with increased water repellency. The solid agrochemical composition may be in the form of pellets or granules. The solid agrochemical composition may be applied to the surface of a crop, such as a leaf, stem or root. The solid agrochemical composition may be a pesticide composition. Increasing the water repellency the surface of the solid agrochemical composition may advantageously slow the release of active ingredients (such as pesticides) from the solid agrochemical composition into soil, allowing the agrochemical composition to be effective for a longer period of time. The polymer used to treat the surface of a solid agrochemical composition is preferably the reaction product of monomers comprising, consisting essentially of, or consisting of one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is selected from one or more of a hydroxycarboxylic acid or a cyclic ester thereof, and wherein the or each second monomer (when present) is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof, a monoalcohol and a polyol (especially a polycarboxylic acid ora reactive equivalent thereof and a polyol). The use of the first aspect and the method of the second aspect may provide a surface of a nonhousehold fibrous substrate with reduced friction. By non-household fibrous substrate we mean a fibrous substrate that is not in the home. In other words, the fibrous substrate is treated with a polymer as defined herein outside of a household setting. The fibrous substrate is preferably treated with the polymer in an industrial setting. Suitably, the fibrous substrate is a thread. The thread may be formed from a natural fibre, such as cotton, or a synthetic fibre, such as polyester. The thread may be a cotton, denim or polyester thread (preferably a cotton or denim thread). The use of the first aspect and the method of the second aspect may provide improved lubrication of the thread outside of a household setting, for example in textile manufacturing. The use of the first aspect may therefore provide the use of a polymer as defined herein as a lubricant for a thread in textile manufacturing. Lubrication of threads in textile manufacturing may advantageously reduce damage to the threads and reduce wear and tear to industrial textile manufacturing equipment in contact with the threads. Suitably, the polymer defined herein may be coated on a surface of the thread and / or on a surface of industrial textile manufacturing equipment in contact with the thread. The polymer as used herein may be formulated as a component of a composition. In other words, the polymer may be comprised in a composition. Thus, in the use or method of the first or second aspect, the polymer may be comprised in a composition. Suitably, the polymer may be comprised in a composition, wherein the composition additionally comprises at least one solvent and optionally one or more surfactants. In the use or method of the first or second aspect, the polymer may be comprised in a composition, wherein the composition additionally comprises at least one solvent and one or more surfactants. The one or more surfactants may be selected from anionic surfactants, cationic surfactants, non-ionic surfactants, and amphoteric or zwitterionic surfactants. Preferably, the one or more surfactants may be independently selected from one or more of a fatty alkyl amphoacetate, an alkyl (poly)glycoside, an acyl glycinate, a sulfosuccinate, an amphodiacetate and a fatty alcohol ether carboxylate. The composition may comprise at least 0.1 wt%, at least 0.5 wt%, at least 1 wt%, at least 2 wt%, at least 5 wt%, or at least 10 wt% of the polymer. The composition may comprise 80 wt% or less, such as 20 wt% or less, for example 10 wt% or less of the polymer. The composition may comprise from 0.1 to 20 wt%, preferably from 0.1 to 10 wt%, for example from 0.5 to 5 wt% of the polymer. The composition may comprise at least 20 wt%, such as at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, or at least 80 wt% of the polymer. The composition may comprise 100 wt% or less, 99 wt% or less, such as 95 wt% or less, for example 90 wt% or less of the polymer. The composition may comprise from 10 to 100 wt%, such as from 10 to 99 wt%, preferably from 20 to 95 wt%, for example from 50 to 90 wt% of the polymer. References herein to the amount of polymer in the composition are intended to refer to the total of the or each polymer as defined herein that is included in the composition. According to a third aspect of the invention, there is provided a composition for treating a surface that is not a surface of a home care substrate, wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, and wherein the composition comprises one or more polymers, wherein the or each polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. The composition is suitable for treating a surface that is not a surface of a home care substrate to provide at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance of the surface. The polymer referred to in relation to the third aspect may comprise the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers as defined herein. The polymer referred to in relation to the third aspect may be the reaction product of monomers consisting of one or more first monomers and optionally one or more second monomers as defined herein. Features of the polymer, and of the first monomers (and the second monomers when present), in relation to the third aspect of the invention are as set out herein in relation to the first and second aspects of the invention. The composition of the third aspect may comprise at least 0.1 wt%, at least 0.5 wt%, at least 1 wt%, at least 2 wt%, or at least 5 wt% of the one or more polymers. The composition may comprise 80 wt% or less, such as 20 wt% or less, for example 10 wt% or less of the one or more polymers. The composition may comprise from 0.1 to 20 wt%, preferably from 0.1 to 10 wt%, for example from 0.5 to 5 wt% of the one or more polymers. The composition of the third aspect may comprise at least 20 wt%, such as at least 30 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, or at least 80 wt% of one or more polymers. The composition of the third aspect may comprise 100 wt% or less, such as 99 wt% or less, such as 95 wt% or less, for example 90 wt% or less of the one or more polymers. The composition of the third aspect may comprise from 10 to 100 wt%, such as from 10 to 99 wt%, preferably from 20 to 95 wt%, for example from 50 to 90 wt% of the one or more polymers. The composition of the third aspect may comprise any suitable solvent, such as for example a polar solvent, such as a polar protic solvent. The solvent may be an aqueous solvent. Thus, the composition may be an aqueous composition. The term “aqueous solvent” herein is considered to mean water or mixtures of water and at least one water miscible solvent. Water miscible solvents may include alcohols and substantially water-miscible organic solvents. The solvent may be a non-aqueous solvent. The non-aqueous solvent suitably comprises an organic solvent, such as an alcohol. The non-aqueous solvent preferably does not comprise any surfactant. Suitable such alcohols for use in the solvent include monohydric alcohols, polyhydric alcohols, alkoxy alcohols and aryloxy alcohol. Suitable alcohols are monohydric alcohols, polyhydric alcohols and alkoxy alcohols. Preferred alcohols are miscible with water. Suitable simple monohydric alcohols include methanol, ethanol, isopropanol and butanol. The solvent may comprise a polyhydric alcohol or an alkoxyalcohol. Suitable alkoxy alcohols include diethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol and 2-butoxyethanol. Suitable aryloxy alcohols include 2-phenoxyethanol. Suitable polyhydric alcohols include glycerol, ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol and 2-methylpentanediol. Suitable polyhydric alcohols include glycerol, ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol and polypropylene glycol. Preferably, the non-aqueous solvent comprises a monohydric alcohol such as isopropanol. The composition of the third aspect may additionally comprise one or more surfactants (in particular when the solvent is an aqueous solvent). Any suitable surfactant(s) may be included, such as for example one or more surfactants selected from anionic surfactants, cationic surfactants, non-ionic surfactants, and amphoteric or zwitterionic surfactants. The composition may comprise an anionic surfactant. Suitable anionic surfactants may include sulfate surfactants (such as mono- or di-alkyl sulfates or alkyl ether sulfates), sulfonate surfactants, alkyl ether carboxylate surfactants, sarcosinate surfactants, phosphate surfactants, succinate surfactants, sulfosuccinate surfactants, sulfoacetate surfactants, isethionate surfactants, taurate surfactants, amino acid surfactants such as glutamates and glycinates, lactylate surfactants, and fatty acid salts. Particularly exemplary salts of the above, where applicable, are the sodium, potassium, ammonium, magnesium and triethanolamine salts. The composition may comprise a cationic surfactant. The cationic surfactant may be an ammonium salt such as an alkyl trimethyl ammonium salt, a dialkyl dimethyl ammonium salt, an alkyl-(N-hydroxyethyl)-dimethyl ammonium salt, or an alkyldimethylbenzylammonium salt (i.e. a benzalkonium salt). The salt may be a halide, hydroxide, sulfate, hydrogensulfate, phosphate, or carboxylate salt. The salt is suitably a halide salt, such as a fluoride, chloride, or bromide salt. The salt may be a carboxylate salt, such as formate or acetate salt. Preferably, the salt is chloride. The composition may comprise a non-ionic surfactant. Suitable non-ionic surfactants for use herein include alcohol alkoxylates (such as alcohol ethoxylates, alcohol propoxylates, and ethylene oxide / propylene oxide copolymer derived surfactants), aliphatic esters, aromatic esters, sugar esters (such as sorbitan esters), alkyl (poly)glycosides, fatty acid alkoxylates (such as fatty acid ethoxylates and fatty acid propoxylates), or polyethylene glycol esters (including partial esters), glycerol esters (including glycerol partial esters and glycerol triesters), fatty alcohols (such as cetearyl alcohol, lauryl alcohol, stearyl alcohol, behenyl alcohol), and alkanolamides. The composition may comprise an amphoteric or zwitterionic surfactant. The amphoteric or zwitterionic surfactant may be selected from betaines (such as alkyl betaines and alkylamidopropyl betaines), amphoacetates, diamphoacetates, and amine oxides (such as alkylamine oxides and alkylamidopropyl amine oxides). Suitable amphoteric or zwitterionic surfactants include lauryl betaine, cocamidopropyl betaine, sodium lauroamphoacetate, sodium cocoamphoacetate, disodium cocoamphodiacetate, lauramine oxide, C12-18 alkyldimethylamine oxide, myristamine oxide, and cocamidopropyl amine oxide. The one or more surfactants may be selected from a fatty alkyl amphoacetate (for example cocoyl amphoacetate, lauryl amphoacetate), an alkyl (poly)glycoside (for example lauryl glycoside), an acyl glycinate (for example cocoyl glycinate), a sulfosuccinate, an amphodiacetate and a fatty alcohol ether carboxylate (for example Cs-12 alkyl ether (6-11 moles EO) carboxylate). The composition of the third aspect may comprise the one or more surfactants in an amount of from 1 to 100 wt%, suitably from 5 to 50 wt%, preferably from 10 to 25 wt% based on the total weight of the one or more polymers. The composition may comprise the one or more surfactants in an amount of from 0.1 to 99 wt%, suitably from 1 to 50 wt%, for example from 10 to 25 wt% or from 0.1 to 20 wt% based on the total weight of the composition. The composition referred to in relation to the first and second aspects of the invention may be a composition according to the third aspect of the invention. Suitably the composition of the third aspect is substantially free of silicon atoms. By substantially free of silicon atoms we mean that the composition contains less than 1 wt%, preferably less than 0.5 wt%, of silicon in the composition. More preferably, the composition is free of silicon atoms, by which we mean that it is not possible to detect silicon in the composition. Suitable methods of measuring the amount of silicon in a composition are well known to those skilled in art and include elemental analysis and inductively coupled plasma (ICP) spectroscopy. According to a fourth aspect of the invention, there is a provided a substrate that is not a home care substrate, wherein a surface of the substrate is treated with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following: (i) cyclic anhydride; (ii) polycarboxylic acid or reactive equivalent thereof; (iii) monocarboxylic acid or ester thereof; (iv) polyol; (v) epoxide compound; (vi) polyfunctional monomer having a reactive amino group; (vii) monoalcohol; and (viii) monofunctional monomer having a reactive amino group. The substrate that has been treated with the polymer is suitably provided with at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance of the surface, compared to a substrate that has not been treated with the polymer. The polymer referred to in relation to the fourth aspect may comprise the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers as defined herein. The polymer referred to in relation to the fourth aspect may be the reaction product of monomers consisting of one or more first monomers and optionally one or more second monomers as defined herein. Features of the substrate, the polymer, and of the first monomers (and the second monomers when present), in relation to the fourth aspect of the invention are as set out herein in relation to the first and second aspects of the invention. The polymer as used in the fourth aspect may be formulated as a component of a composition. In other words, the substrate of the fourth aspect may be treated with a composition comprising the polymer. Suitably, the polymer may be comprised in a composition, wherein the composition additionally comprises at least one solvent and optionally one or more surfactants. The composition referred to in relation to the fourth aspect of the invention may be a composition according to the third aspect of the invention. The substrate may be selected from a construction material or a seed. The substrate may be a construction material. The construction material may be plasterboard, gypsum, stucco, or concrete. Preferably, the construction material is plasterboard. Plasterboard typically comprises a gypsum core disposed between two sheets of paper. The polymer as defined herein may be present at a surface of the gypsum core and / or the sheets of paper. The polymer may further be present within the gypsum core. This may be achieved by admixing the polymer into a slurry of stucco and water as an additive during the production of the plasterboard. The substrate may be a seed. By “seed” we mean a plant seed. A surface of the seed is suitably treated with the polymer as defined herein. Examples The invention will now be further described with reference to the following non-limiting examples. Example 1 - general method for synthesis of polymers using hydroxycarboxylic acid(s) as a monomer The hydroxycarboxylic acid monomer(s) were combined with optional further monomer(s) (where used). Tin(ll) ethylhexanoate (0.5 wt% relative to the total weight of monomers) was added. The reaction mass was heated at 160°C for 6 hours. The resulting polymer was decanted 5 from the reaction flask, and no further purification was carried out. Example 2 - general method for synthesis of polymers using cyclic ester of a hydroxycarboxylic acid as a monomer 10 The cyclic hydroxycarboxylic ester(s) were combined with an initiator (second monomer) and tin(ll) ethylhexanoate (0.5 wt% relative to the total weight of monomers) was added. The reaction mass was heated at 140°C for 6 hours. The resulting polymer was decanted from the reaction flask, and no further purification was carried out. 15 Polymers 1 to 19 were prepared, using the monomers, reaction stoichiometries and synthesis procedures as set out in Table 1. Table 1 Polymer Hydroxy carboxylic acid (or cyclic ester) 1 Hydroxy carboxylic acid (or cyclic ester) 1 Further monomer 1 Further monomer 2 Further monomer 3 Prepared according to general example Molar ratio of monomers 1 Menthide Ethylene glycol 2 1 : 0.05 2 DL-Lactide s-Caprolactone (2-Dodecen-1-yl) succinic anhydride 2 1 : 1 : 0.01 3 DL-Lactide Citric acid 2 1 : 0.01 4 Ricinoleic acid 1 Homo polymer 5 Ricinoleic acid Glycolic acid 1 1 : 1 6 Ricinoleic acid Glycolic acid 1 1 : 2 7 Ricinoleic acid Citric acid 1 1 : 1 8 Ricinoleic acid Malic acid 1 1 : 1 9 Ricinoleic acid Mandelic acid 1 1 : 1 10 Ricinoleic acid Glycerol carbonate 1 1 : 1 11 Ricinoleic acid 1,6-Hexanediol Diglycolic acid 1 0.9 : 0.05 : 0.05 12 Ricinoleic acid 1,6-Hexanediol Diglycolic acid 1 0.7 : 0.15 : 0.15 13 Ricinoleic acid 1,6-Hexanediol Diglycolic acid 1 0.6 : 0.2 : 0.2 14 Ricinoleic acid 1,6-Hexanediol Diglycolic acid 1 0.5 : 0.25 : 0.25 15 Ricinoleic acid 1,6-Hexanediol Diglycolic acid PPG 2000 1 0.8 : 0.05 : 0.1 : 0.05 16 Ricinoleic acid 1,6-Hexanediol Diglycolic acid PPG 2000 1 0.7 : 0.075 : 0.15 : 0.075 17 Ricinoleic acid 1,6-Hexanediol Diglycolic acid PPG 2000 1 0.6 : 0.1 : 0.2 : 0.1 18 Ricinoleic acid Tri methylol propane Diglycolic acid 1 0.7 : 0.15 : 0.15 19 Ricinoleic acid Tri methylol propane Diglycolic acid 1 0.6 : 0.2 : 0.2 Table 2 - abbreviations and chemical names PPG Poly (propylene glycol) Example 3 - Seed flow test Seed treatment slurries A and B were prepared having the following compositions: Seed Treatment slurry A Component Amount (wt%) Comment Pesticide 0 Pigment 12.5 Pigment was Red 48:2 (35 wt% dispersion in water) Coating 37.5 Carnauba wax-based emulsion Polymer 2.5 Water to 100 Seed Treatment slurry B Component Amount (wt%) Comment Pesticide 35 Azoxystrobin suspension concentrate (SC) 250 g / L Coating 30 Carnauba wax-based emulsion Polymer 1.6 Water to 100 Commercial corn seeds (Viking 99-00 hybrid, 100 g) were mixed with seed treatment slurry (either A or B as specified in Table 3, 1 mL) and stood at ambient temperature and relative humidity (RH) 50 % for 5 minutes. The treated seeds were transferred to a stainless steel funnel with an opening of 30 mm diameter and a stoppered outlet. The stopper was removed and the time taken for the funnel contents to empty was recorded. The control for each test was a seed treatment slurry equivalent to either A or B (depending on which was used) but without the specified polymer. Where the time taken for the funnel to empty was lower when using the additized seed treatment slurry, compared to the control, this was considered to be a “pass”. In other words, the polymer was providing a lubricating effect to the treated seeds and enabling faster flow. The results are shown in Table 3 below. Table 3 Polymer Seed treatment slurry Performance in seed flow test 5 A Pass 7 B Pass 17 B Pass Example 4 - Simulated Rain Fastness Test This test simulates the interaction of a rain droplet with a substrate (e.g. a leaf) that has been coated with a pesticide formulation. A precleaned glass slide was treated with a drop of solution A (~ 0.3 mL) dispensed using a disposable pipette, to form a wet film on the slide. Solution A contained the following components : Component Amount (wt%) Comment Polyvinylpyrrolidone) 20 Agrimer 90 (MW 1,000,000 -1,700,000 a product of Ashland Inc, Delaware, US) Rhodamine 6B dye 0.1 Polymer 10 Water to 100 The slide was oven dried overnight (54 °C) and allowed to cool to ambient temperature. The dried PVP film was further secured to the glass slide using 3M Scotch Magic™ tape but leaving a square central region of the dried PVP film exposed. A droplet of deionized water (3 pL) was added to exposed area of the dried PVP film. After standing for 90 seconds, excess water was removed by gently dabbing with a laboratory wipe. The exposed area was visually inspected to determine the extent of dissolution or disintegration of the PVP film. The control sample for the experiment was Solution A without the specified polymer. The polymers under test were considered to “pass” when the extent of dissolution or disintegration of the PVP film formed using Solution A (containing the polymer) was less than when using the control sample without the polymer. The results are shown in Table 4 below. Table 4 Polymer Performance in Simulated Rain Fastness Test 5 Pass 17 Pass Example 5 - Preparation of substrates and compositions for use in evaluation of improvement of shine, friction reduction and water repellency (Examples 6 to 8) Prior to treatment with the specified polymers and evaluation of the resulting properties (reduced friction, water repellency, improved visual appearance) the substrates used in the experiments were prepared as shown in Table 5. Table 5 Substrate Preparation method Interior car panel (plastic) UV - ozone cleaning, 10 minutes Denim Used as obtained Velour Black card (smooth, 250GSM) Leather The specified polymers were deposited on the test substrates as composition types as shown in Table 6. Table 6 Composition type Description X Emulsion containing polymer (1wt%), sodium lauroamphoacetate (0.2wt%)*, ethanol (5wt%)** and water to 100wt% Y Solution of polymer (1wt%) in ethanol * of a 25 wt% aqueous solution ** ethanol was only added if the polymer was not miscible in a solution of sodium lauroamphoacetate (0.2 wt%) in water The prepared substrates and composition types were used in Examples 6 to 8. Example 6 - Shine improvement test Shine improvement was determined by spraying a 1wt% active solution of the polymer (composition type X) onto the substrate (leather) and visually observing the surface of the substrate after drying. The visual observation was compared to the untreated substrate. A “pass” result indicates that a visual improvement in shine was observed for the polymer-treated substrate. The results are shown in Table 7. Table 7 Substrate Polymer Result Leather 5 Pass Example 7 - Friction reduction test Substrates, which were initially prepared according to Table 5, were treated by applying a liquid composition containing 1wt% of the polymer. For denim substrates, these were treated by soaking for 1 hour (composition type X). Excess liquid was removed. The substrates were dried (60°C) then cooled to ambient temperature before running the friction test. For black card, this was sprayed with the polymer composition (composition type Y) and left to dry at ambient temperature before running the friction test. For leather substrates, these were treated by spraying with the polymer composition (composition type X) and allowing to dry at ambient temperature prior to running the friction test. For the friction test, a weighted block (250g) having baize fabric attached to its surface was then rubbed across the treated substrate. The results were observed relative to an untreated substrate. Each test was repeated twice, with two different (independent) operators. A “pass” result indicates that both operators recorded lower friction for the treated substrate, compared to the untreated substrate. The results are shown in Table 8. Table 8 Substrate Polymer Result Denim 5 Pass Black Card 5 Pass Leather 5 Pass Example 8 - Water repellency test Substrates, which were initially prepared according to Table 5, were treated by applying a liquid composition of type X or Y. For interior car panel (plastic rim) substrates, a 1wt% solution of the polymer compound was sprayed onto the surface (composition type X) and the surface was buffed using a Car Buffer Polisher with a microfibre cloth attachment before carrying out the droplet test. For velour substrates, these were treated by spraying with the polymer composition (composition type X) and allowing to dry at ambient temperature prior to carrying out the droplet test. For other substrate types, these were treated as already described above in Examples 6 and 7. For the droplet test, after drying, the initial shape and absorption time of a de-ionized water droplet dropped on the treated surface was visually inspected. The results were observed relative to a substrate treated with an identical composition other than the polymer being absent. A “pass” result indicates that the water droplet did not absorb into the substrate or was absorbed at a much lower speed than the comparative tests. For non absorbent substrates the spreading behaviour of the water droplet was visually compared to that on an identically treated surface, other than the polymer being absent. A “pass” result indicated less droplet spreading on the treated surface relative to the comparative tests. The results are shown in Table 9. Table 9 Substrate Polymer Result Interior Car Panel (Plastic) 5 Pass Velour 5 Pass Black Card 5 Pass Leather 5 Pass Unless otherwise stated herein, the reference to “liquid”, “gel” and “solid” refer to a state at 25 °C and standard pressure (101,325 Pa). Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, and 5 drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, and drawings) 10 may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention 15 extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A use of a polymer to treat a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance; and wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following:(i) cyclic anhydride;(ii) polycarboxylic acid or reactive equivalent thereof;(iii) monocarboxylic acid or ester thereof;(iv) polyol;(v) epoxide compound;(vi) polyfunctional monomer having a reactive amino group;(vii) monoalcohol; and(viii) monofunctional monomer having a reactive amino group.

2. A method of treating a surface, wherein the surface is not a surface of a home care substrate and wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, the method comprising contacting the surface with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following:(i) cyclic anhydride;(ii) polycarboxylic acid or reactive equivalent thereof;(iii) monocarboxylic acid or ester thereof;(iv) polyol;(v) epoxide compound;(vi) polyfunctional monomer having a reactive amino group;(vii) monoalcohol; and(viii) monofunctional monomer having a reactive amino group.

3. The use or method according to claim 1 or 2, wherein the polymer is a polyester.

4. The use or method according to any preceding claim, wherein the polymer is a homo polymer.

5. The use or method according to claim 1 or 2, wherein the polymer is a copolymer.

6. The use or method according to any preceding claim, wherein the or each first monomeris a hydroxycarboxylic acid or a cyclic ester thereof selected from one or more of glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, and DL-lactide.

7. The use or method according to claim 4, wherein the polymer is a homopolymer and the first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from one of glycolic acid, lactic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxystearic acid (preferably 12-hydroxystearic acid), dihydroxystearic acid, 2,2-bis(hydroxymethyl)propionic acid, mandelic acid, ricinoleic acid, malic acid, tartaric acid, citric acid, y-butyrolactone, 6-valerolactone, s-caprolactone, menthide, D-lactide, L-lactide, and DL-lactide.

8. The use or method according to claim 4, wherein the polymer is a homopolymer and the first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from one of hydroxystearic acid and ricinoleic acid.

9. The use or method according to claim 5, wherein the polymer is a copolymer and the or each first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from two or more of DL-lactide, citric acid ors-caprolactone; or the each first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from two or more of ricinoleic acid, glycolic acid, mandelic acid, malic acid, and citric acid.

10. The use or method according to claim 4, wherein the polymer is a copolymer and the or each first monomer is a hydroxycarboxylic acid or the cyclic ester thereof selected from one or more of ricinoleic acid, glycolic acid, citric acid and malic acid, and the or each second monomer is selected from one or more of a polycarboxylic acid or a reactive equivalent thereof and a polyol.

11. The use or method according to any preceding claim, wherein the polymer has a number average molecular weight of from 1,000 to 50,000 Daltons, preferably from 1,000 to 15,000 Daltons (for example from 2,000 to 7,000 Daltons).

12. The use or method according to any preceding claim, wherein the polymer is substantially free of silicon atoms.

13. The use or method according to any preceding claim, wherein the surface is an industrial surface.

14. The use or method according to claim 13, wherein the industrial surface is a surface that is found in the manufacturing industry, the packaging industry, construction industry, the automotive industry, the aviation industry, the agricultural industry, or the mining industry.

15. The use or method according to claim 14, wherein the industrial surface is found in the manufacturing industry.

16. The use or method according to claim 14, wherein the industrial surface is found in the packaging industry.

17. The use or method according to claim 14, wherein the industrial surface is found in the construction industry.

18. The use or method according to claim 14, wherein the industrial surface is found in the automotive industry.

19. The use or method according to claim 14, wherein the industrial surface is found in the aviation industry.

20. The use or method according to claim 14, wherein the industrial surface is found in the agricultural industry.

21. The use or method according to claim 14, wherein the industrial surface is found in the mining industry.

22. The use or method according to any preceding claim, wherein surface is selected from the surface of an extruded product (such as a pellet, granule, or film), a mould, paper packaging, a construction material (such as plasterboard, gypsum, stucco, or concrete), a vehicle (such as a window, tyre, vehicle body, or vehicle interior), a plant (such as a seed), a solid agrochemical composition, or a non-household fibrous substrate.

23. The use or method according to any preceding claim, which provides a surface of plasterboard, gypsum or stucco with increased water repellency.

24. The use or method according to any preceding claim, wherein the polymer is comprised in a composition, wherein the composition additionally comprises at least one solvent and optionally one or more surfactants.

25. The use or method according to claim 24, wherein the composition comprises one or more surfactants selected from anionic surfactants, cationic surfactants, non-ionic surfactants, and amphoteric or zwitterionic surfactants.

26. The use or method according to claim 25, wherein the one or more surfactants are independently selected from one or more of a fatty alkyl amphoacetate, an alkyl (poly)glycoside, an acyl glycinate, a sulfosuccinate, an amphodiacetate and a fatty alcohol ether carboxylate.

27. The use or method according to any of claims 24 to 26, wherein the composition comprises from 0.1 to 20 wt%, preferably from 0.1 to 10 wt%, for example from 0.5 to 5 wt% of the polymer.

28. A composition for treating a surface that is not a surface of a home care substrate, wherein treating the surface provides at least one effect selected from (a) increased water repellency, (b) reduced friction, and (c) improved visual appearance, and wherein the composition comprises one or more polymers, wherein the or each polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following:(i) cyclic anhydride;(ii) polycarboxylic acid or reactive equivalent thereof;(iii) monocarboxylic acid or ester thereof;(iv) polyol;(v) epoxide compound;(vi) polyfunctional monomer having a reactive amino group;(vii) monoalcohol; and(viii) monofunctional monomer having a reactive amino group.

29. The composition according to claim 28, wherein the composition comprises at least 0.1 wt%, such as from 0.1 to 20 wt%, preferably from 0.1 to 10 wt%, for example from 0.5 to 5 wt% of the one or more polymers.

30. The composition according to claim 28 or 29, wherein the composition additionally comprises one or more surfactants.

31. The composition according to claim 30, wherein the one or more surfactants are independently selected from anionic surfactants, cationic surfactants, non-ionic surfactants, and amphoteric or zwitterionic surfactants.

32. The composition according to claim 31, wherein the one or more surfactants are independently selected from one or more of a fatty alkyl amphoacetate, an alkyl (poly)glycoside, an acyl glycinate, a sulfosuccinate, an amphodiacetate and a fatty alcohol ether carboxylate.

33. A substrate that is not a home care substrate, wherein a surface of the substrate is treated with a polymer, wherein the polymer is the reaction product of monomers comprising one or more first monomers and optionally one or more second monomers, wherein the or each first monomer is a hydroxycarboxylic acid or a cyclic ester thereof and the or each second monomer is one or more of the following:(i) cyclic anhydride;(ii) polycarboxylic acid or reactive equivalent thereof;(iii) monocarboxylic acid or ester thereof;(iv) polyol;(v) epoxide compound;(vi) polyfunctional monomer having a reactive amino group;(vii) monoalcohol; and(viii) monofunctional monomer having a reactive amino group.A