A polyesteramide polymer

Abstract

The present invention provides a water-soluble biodegradable polyesteramide polymer. Said polyesteramide has a good balance of crystallinity, water-solubility, thermal and mechanical properties, and biodegradability and is a promising polymer for industrialization.

Description

A polyesteramide polymerRELATED APPLICATIONS[1] This application claims priorities of IN provisional application 202311058192 filed on August 30, 2023, and of EP patent application 23203689.7 filed on October 16, 2023, the whole content of each of these applications being incorporated herein by reference for all purposes.FIELD OF THE INVENTION[2] The present invention provides a water-soluble biodegradable polyesteramide polymer.BACKGROUND OF THE INVENTION[3] Poly(esteramide)s (PEAs) are very important synthetic polymers with applications in many fields. The combination of the thermal and mechanical properties of polyamides with the biocompatibility and biodegradability of polyesters affords biomaterials of great interest.[4] PEAs derived from amino acids, diols, and dicarboxylic acids have been investigated for biomedical applications as they offer advantageous aspects of both natural and synthetic polymers. The incorporated amino acids can be recognized by biological systems and their enzymatic biodegradation leads to metabolically-degradable building blocks, while their properties can be readily tuned by varying their monomer components.[5] Synthesis of various PEAs mainly by three different methods, melt polycondensation (MP), interfacial polycondensation (IP), and solution polymerization (SP). Among these methods, melt polycondensation is favorable from an industrial point of view because the polymer does not require tedious post-polymerization treatment and also no use of harmful organic solvents. However, the MP method is challenging for right choice of monomers, high temperature stability of monomers, and minimum undesired side reactions during high thermal and vacuum processes. Thus, the choice of monomers is very limited.[6] Polymer Degradation and Stability 181 (2020) 109323 teaches synthesis and characterization of PEAs based on amino acid, diols and dicarboxylic acid monomers by different methods. However, water-solubility is not specifically mentioned in this article.[7] J. Mater. Sci. Mater. Med. 22 (2011) 469-479 reports an ionic charged water soluble arginine-based poly(ester amide)(Arg-PEAs), which consists of three nontoxic building blocks: L-arginine, diols and dicarboxylic acids. Arg-PEAs were found to have good solubility in water and many other polar solvents. However, some other properties, such as mechanical and thermal properties, and biodegradability are not well balanced if only water-solubility is adjusted. The Arg- PEAs obtained have a cationic nature.[8] Without wishing to be bound to any particular theory, the monomers selected can well tune the hydrophilicity-lipophilicity balance (HLB) and therefore the water- soluble biodegradable polyesteramide of the present invention has a good balance of crystallinity, water-solubility, mechanical and thermal properties, and biodegradability.[9] In addition, the water-soluble biodegradable polyesteramide of the present invention has an anionic nature, which is useful for many applications, such as agrochemical formulations.

[0010] Furthermore, the polyesteramide of the present invention can easily be prepared by melt polycondensation (MP) and therefore is a promising polymer for industrialization.

[0011] In another aspect of the present invention, a process for synthesizing a polyesteramide polymer is provided.

[0012] Finally, the present invention also relates to the use of given polyesteramide polymer as dispersant of active ingredients.BRIEF OF DESCRIPTION OF DRAWINGS

[0013] Fig.1. A typical1H-NMR of Ex. 4 polymer in DMSO-de at room temperature showing characteristics peaks of different protons;

[0014] Fig.2. A typical13C-NMR of Ex. 4 polymer in DMSO-de at room temperature showing characteristics peaks of different carbons;

[0015] Fig.3. Thermogravimetric analysis (TGA) plot of Ex. 4 polymer.

[0016] Fig.4. Differential scanning calorimetry (DSC) of second heating cycle of Ex. 4 polymer.DETAILED DESCRIPTION OF THE INVENTION

[0017] The polyesteramide polymer of the present invention is prepared by polycondensation of at least the following monomers (a) to (d):(a) an aliphatic / aromatic unsulfonated dicarboxylic acid / ester;(b) an aliphatic diol;(c) an aliphatic / aromatic sulfonated dicarboxylic acid / ester;(d) a compound comprising two ester functions and two amide functions [DEDA],

[0018] The aliphatic unsulfonated dicarboxylic acid / ester according to the invention may be linear or cyclic. Preferred linear aliphatic unsulfonated dicarboxylic acids / esters according to the invention are alkyldicarboxylic acids / esters of formula ROOC-(CH2)n-COOR (I) where n = 2-4 and R is H, a Ci to Cs alkyl or phenyl group. Preferred cycloaliphatic unsulfonated dicarboxylic acids / esters according to the invention are based on cycles with 5 or 6 carbon atoms i.e. cyclopentanedicarboxylic acids / alkyl esters or cyclohexanedicarboxylic acids / alkyl esters, in particular 1 ,2-cyclopentanedicarboxylic acid, 1 ,3- cyclopentanedicarboxylic acid, 1 ,3-cyclohexanedicarboxylic acid or 1 ,4- cyclohexanedicarboxylic acid and their corresponding alkyl esters where the alkyl group can vary from methyl to octyl or can be a phenyl group.

[0019] Preferred aromatic unsulfonated dicarboxylic acids / esters according to the invention are terephthalic acid / alkyl esters and isophthalic acid / alkyl esters where the alkyl group can vary from methyl to octyl or can be a phenyl group.

[0020] The aliphatic / aromatic unsulfonated dicarboxylic acid / ester of the invention is preferably an aliphatic one, more preferably a cyclohexane derivative. In particular 1 ,4-cyclohexanedicarboxylic acid (CHDA) gives good results in the frame of the present invention.

[0021] The aliphatic diol used in the present invention can be a linear aliphatic diol selected from the group consisting of alkyl diols like ethylene glycol or propylene glycol, diethylene glycol, triethylene glycol or a polyethylene glycol having an ethylene oxide number ranging from 4 to 75. Alternatively, it can be a cyclic saturated diol preferably comprising 5 or 6 C atoms i.e. a cyclopentane diol or a cyclohexane diol, in particular 1 ,2-cyclopentane diol, 1 ,3-cyclopentane diol, 1 ,3- cyclohexane diol or 1 ,4-cyclohexane diol.

[0022] Preferably, linear aliphatic diols are used, more preferably alkyl diols, in particular ethylene glycol (EG).

[0023] As previously mentioned, the polyesteramide polymer of the present invention has anionic nature, which can be brought by any one of the anions contained in the polymer, especially the sulfonate anion(s) of monomer (c).

[0024] The aliphatic / aromatic sulfonated dicarboxylic acid / ester has at least one sulfonic acid group, preferably in the form of an alkali metal (preferably sodium) sulfonate, and two acid / ester functional groups attached to one or a number of aromatic rings, when aromatic dicarboxylic acids or their alkyl diesters are involved, or to the aliphatic chain when aliphatic dicarboxylic acids / alkyl diesters are involved, where the alkyl group can vary from methyl to octyl or can be a phenyl group.

[0025] Aromatic sulfonated dicarboxylic acids / esters monomers that can be used in the frame of the invention are preferably isophthalic acid / esters, terephthalic acid / esters and naphthalenedicarboxylic acids / esters. Preferred ones are 2- sodiosulfoisophthalic acid / ester, 4-sodiosulfoisophthalic acid / ester, 5- sodiosulfoisophthalic acid / ester, 2-sodiosulfoterephthalic acid / ester, 2,6- dicarboxyl naphthalene-4-sodiosulfonic acid / ester and 2,6-dicarboxyl naphthalene-7-sodiosulfonic acid / ester. Aliphatic sulfonated dicarboxylic acids / esters that can be used in the frame of the present invention are dialkyl sodium sulfosuccinates.

[0026] Aromatic sulfonated dicarboxylic acid / ester monomers are preferably used in the frame of the invention, more preferably 5-sodiosulfoisophthalic acid / esters, in particular 5-sodiosulfoisophthalic acid (SSIA).

[0027] Preferably, the compound comprising two amide functions and two ester functions [DEDA] used in the present invention is a compound having the general formula (II):wherein:Ri is an arenediyl, an alkanediyl or a cycloalkanediyl;R2 and R3, same or different from each other, are hydrogen, or a straight, branched, cyclic hydrocarbon radical, which is optionally interrupted by one or several heteroatom(s) and / or which is optionally substituted by one or several functional group(s); andR4 and Rs, same or different from each other, are an alkyl.

[0028] By “arenediyl” is meant a bivalent radical obtained by the removal of one hydrogen atom attached to each of two carbon atoms contained in an aromatic ring of an arene, including, but not limited to phenylene, furylene. The arenediyl includes substituted or unsubstituted arenediyls. The arenediyl group can have one, two, three or four substituents independently selected from the group consisting of: alkyl, alkenyl, alkynyl, alkoxy, alkylated amino, carboxyl, ester, cyano, nitro and halogen.

[0029] By “alkanediyl” is meant a bivalent radical obtained by the removal of two hydrogen atoms attached to one or two carbon atom(s) of an alkane, in particular C1-C20 alkanediyl. The alkanediyl includes substituted or unsubstituted alkanediyls.

[0030] By “cycloalkanediyl” is meant a bivalent radical obtained by the removal of two hydrogen atoms attached to one or two carbon atom(s) of a clycoalkane, including, but not limited to cyclohexanediyl. The cycloalkanediyl includes substituted or unsubstituted alkanediyls.

[0031] The functional group optionally substitued to R2 or R3 can be selected from the group consisting of alkyl, alkenyl, alkynyl, alkoxy, alkylated amino, carboxyl, ester, cyano, nitro and halogen.

[0032] The optional heteroatom in R2 or Rs can be O, S, N, F, Cl or Br.

[0033] Preferably, R2 and R3, same or different from each other, are hydrogen, or straight or branched hydrocarbon radical, more preferably hydrogen, or a straight or branched alkyl, in particular a straight or branched C1-C10 alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl and tert-butyl.

[0034] In some preferred embodiments, R2 and R3are the same.

[0035] R4 and Rs can be a straight or branched alkyl. Preferably, R4 and Rs, same or different from each other, are a C1-C10 alkyl, more preferably a C1-C5 alkyl.

[0036] In some preferred embodiments, R4 and Rs are the same.

[0037] In a preferred embodiment, the polyesteramide polymer of the present invention is prepared by polycondensation of the following monomers (a) to (d):(a) an aliphatic unsulfonated dicarboxylic acid / ester, preferably a cyclohexane derivative, in particular 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) a linear aliphatic diol, in particular ethylene glycol (EG);(c) an aromatic sulfonated dicarboxylic acid / ester, preferably 5- sodiosulfoisophthalic acid / ester, in particular 5-sodiosulfoisophthalic acid (SSIA);(d) a compound having the general formula (II); wherein:Ri is a cycloalkanediyl, in particular cyclohexanediyl;R2 and R3 are hydrogen, or a straight or branched C1-C10 alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl and tert-butyl; andR4 and Rs are C1-C5 alkyl.

[0038] A particularly preferred polyesteramide of the invention is prepared by polycondensation of the following monomers (a) to (d):(a) 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) ethylene glycol (EG);(c) 5-sodiosulfoisophthalic acid (SSIA);(d) DEDA having the formula (III) (hereinafter “CY-GLA”):

[0039] In a preferred embodiment, the polyesteramide polymer of the present invention is prepared by polycondensation of the following monomers (a) to (d):(a) an aliphatic unsulfonated dicarboxylic acid / ester, preferably a cyclohexane derivative, in particular 1,4-cyclohexanedicarboxylic acid (CHDA);(b) a linear aliphatic diol, in particular ethylene glycol (EG);(c) an aromatic sulfonated dicarboxylic acid / ester, preferably 5- sodiosulfoisophthalic acid / ester, in particular 5-sodiosulfoisophthalic acid (SSIA);(d) a compound having the general formula (II); wherein:Ri is an arenediyl, in particular phenylene, furylene;R2 and R3 are hydrogen, or a straight or branched C1-C10 alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl and tert-butyl; andR4 and Rs are C1-C5 alkyl.

[0040] When R1 is a furylene, the monomer is preferably derived from bio-based furan dicarboxylic acid and amino acid. The Applicant has now found that such a readily available monomer can provide high thermal and mechanical stability, heteroaromatic furan building blocks, and biodegradability to the water-soluble biodegradable polyesteramide of the present invention.

[0041] A particularly preferred polyesteramide of the invention is prepared by polycondensation of the following monomers (a) to (d):(a) 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) ethylene glycol (EG);(c) 5-sodiosulfoisophthalic acid (SSIA);(d) DEDA having the formula (IV) (hereinafter “Fll-GLA”):

[0042] A particularly preferred polyesteramide of the invention is prepared by polycondensation of the following monomers (a) to (d):(a) 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) ethylene glycol (EG);(c) 5-sodiosulfoisophthalic acid (SSIA);(d) DEDA having the formula (V) (hereinafter “TE-GLA”):

[0043] In a preferred embodiment, the polyesteramide polymer of the present invention is prepared by polycondensation of the following monomers (a) to (d):(a) an aliphatic unsulfonated dicarboxylic acid / ester, preferably a cyclohexane derivative, in particular 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) a linear aliphatic diol, in particular ethylene glycol (EG);(c) an aromatic sulfonated dicarboxylic acid / ester, preferably 5- sodiosulfoisophthalic acid / ester, in particular 5-sodiosulfoisophthalic acid (SSIA);(d) a compound having the general formula (II); wherein:Ri is an alkanediyl, in particular C1-C20 alkanediyl;R2 and R3 are hydrogen, or a straight or branched C1-C10 alkyl, such as methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl and tert-butyl; andR4 and Rs are C1-C5 alkyl.

[0044] A particularly preferred polyesteramide of the invention is prepared by polycondensation of the following monomers (a) to (d):(a) 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) ethylene glycol (EG);(c) 5-sodiosulfoisophthalic acid (SSIA);(d) DEDA having the formula (VI) (hereinafter “Sll-GLA”):

[0045] The present invention also concerns a novel and inventive polyesteramide polymer comprising the following repeat units: CHDA-EG, SSIA-EG and DEDA- EG(e.g. FU-GLA-EG, CY-GLA-EG, TE-GLA-EG and SU-GLA-EG).

[0046] Advantageously, the ratio of the moles of monomer (b) to the total moles of monomers (a), (c) and (d) in the polymer backbone is about 1 :1 , for instance from 0.8 to 1.2, preferably from 0.9 to 1.1. Thus, the polyesteramide polymer of the present invention is preferably derived from a reaction mixture in which the total mole percentage of monomers (a), (c) and (d) is 50 %, based on the total moles of monomers (a), (b) (c) and (d). Particularly, monomer (c) has a mole percentage from 0.01 to 10 mol% and monomer (d) has a mole percentage from 0.01 to 25 mol%, based on the total moles of monomers (a), (b) (c) and (d). The amount of monomers (a) can be adjusted to achieve a total mole percentage of 50 %. Hence, monomer (a) preferably has a mole percentage from 15 to 49.98 mol%.

[0047] It can be understood by the skilled person that excess monomer (b) can be present in the reaction mixture when it is also used as a solvent of solid reactants. Said excess monomer (b) can be added at the beginning of polymerization reaction or during polymerization reaction. In a preferred embodiment, the polymerization can be performed with a mixture in which the ratio of the moles of monomer (b) to the total moles of monomers (a), (c) and (d) is about 1 :1 to 6:1 and more preferably 3:1 to 5:1.

[0048] The weight average molecular weight of the polyesteramide can vary from 5000 to 30000g / mol.

[0049] Preferred polyesteramides according to the invention comprise 15-30 mol% of aromatics (e.g. SSIA and DEDA comprising aromatic ring) in order to promote / facilitate biodegradability.

[0050] The polyesteramide polymer of the present invention has a solubility in distilled water of at least 1 wt%, preferably at least 1.5 wt% more preferably at least 5 wt% at room temperature.

[0051] The present invention also concerns a process for synthesizing the above described polyesteramide polymer by polycondensation of monomers (a), (b), (c) and (d), preferably in the presence of a catalyst. This catalyst is preferably a hydrolysis-stable catalyst, more preferably chosen from chelates of titanium salts or of zirconium salts derived from ethanol amines, separately and / or mixtures or solutions thereof. In particular, Titanium(IV) (triethanolaminato)isopropoxide gives good results. This compound is available as a 80wt% solution in isopropanol under the brand name Tyzor® TE.

[0052] The polycondensation according to the invention is preferably initiated on the mixture of all monomers (a) to (d) i.e. monomers (a), (b), (c) and (d) are first mixed and then, reacted by polycondensation, preferably by raising temperature and / or reducing pressure. Alternatively, the polycondensation can be initiated on a mixture of only some of the monomers, the others being introduced in a delayed manner. Still another possibility is to prepare 2 or more prepolymers by polycondensation and then, to proceed to transesterification of the prepolymers.

[0053] In a preferred embodiment, the procedure for the preparation of the polyesteramides according to the invention is as follows. First, all the monomers are mixed in a reaction vessel and the mixture is heated from about 110 °C to 200 °C, preferably from 120 °C to 180 °C under a nitrogen blanket. The reaction mixture is then preferably maintained at the same temperature for 30 to 240 minutes, preferably for 60 to 180 minutes under agitation. Subsequently, the reaction temperature is preferably raised to 200 °C and gradually a reduced pressure of 50 to 300 mbar, preferably of 100 to 200 mbar is achieved; under this condition, diol, such as ethylene glycol starts distilling and is preferably collected in a receiver. The reaction temperature is then preferably increased to between about 210 °C and 250 °C under reduced pressure. As the reaction achieves the desired temperature, the pressure is then preferably further reduced to about 10 mbar to 50 mbar, preferably to about 20 to 40 mbar. The reaction is then preferably maintained for 30 to 240 minutes, preferably for 60 to 180 minutes in this condition after which the polymer can be discharged in hot condition.

[0054] The present invention also relates to the use of given polyesteramide polymer as dispersant of active ingredients.

[0055] EXAMPLES

[0056] Materials2,5-Furandicarboxylic acid (CAS no: 3238-40-2), TCI Chemicals (India); 1 ,4-Cyclohexanedicarboxylic acid (CAS no: 1076-97-7), Sigma-Aldrich; Thionyl chloride (CAS no: 7719-09-7), SD fine-chem;- Anhydrous / V, / V-dimethylformamide (CAS no: 68-12-2), Sigma-Aldrich; Glycine methyl ester hydrochloride (CAS no: 5680-79-5), TCI;- Anhydrous dichloromethane (CAS no: 75-09-2), Sigma-Aldrich; Triethylamine (CAS no: 121-44-8), Sigma-Aldrich;5-Sodiosulfoisophthalic acid (CAS No: 6362-79-4), Sigma-Aldrich; Ethylene glycol (CAS no: 107-21-1), SD fine-chem;Tyzor® TE organic titanate (CAS no: 74665-17-1), Sigma-Aldrich.

[0057] Diacid to diacyl chloride (2,5-furandicarbonyl dichloride)

[0058] A two-neck 250 mL round-bottom flask was fitted with a condenser, magnetic stirrer and oil bath. The required amount of 2,5-Furandicarboxylic acid was charged into the reaction vessel and purged with N2 gas two times. Next, freshly distilled SOCI2 (10 equiv.) and a catalytic amount of anhydrous DMF (0.04 equiv.) were introduced into the reactor and the mixture was refluxed at 80 °C for 5 h with constant stirring. The condenser was connected to a washing bottle (minimum two in series), filled with a concentrated sodium hydroxide (NaOH) aqueous solution. After the reaction, the excess of SOCI2 and DMF was removed under vacuum at room temperature and collected in a trap cooled with dry ice and acetone. After removal of most of the liquid, the reaction mass was further dried under high vacuum at 55 °C for 2 h followed by at room temperature for 4 h. The product was stored under an inert atmosphere and used for the next step without further purification.

[0059] Diacid to diacyl chloride (1 ,4-cyclohexanedicarbonyl dichloride)

[0060] A two-neck 250 mL round-bottom flask was fitted with a condenser, magnetic stirrer and oil bath. The required amount of 1 ,4-cyclohexanedicarboxylic acid was charged into the reaction vessel and purged with N2 gas two times. Next, freshly distilled SOCI2 (10 equiv.) and a catalytic amount of anhydrous DMF (0.05 equiv.) were introduced into the reactor and the mixture was refluxed at 80 °C for 6 h with constant stirring. The condenser was connected to a washing bottle (minimum two in series), filled with a concentrated sodium hydroxide (NaOH) aqueous solution. After the reaction, the excess of SOCI2 and DMF was removed under vacuum at room temperature and collected in a trap cooled with dry ice and acetone. After removal of most of the liquid, the reaction mass was further dried under high vacuum at 60 °C for 2 h followed by at room temperature for 5 h. The product was stored under an inert atmosphere and used for the next step without further purification.

[0061] Diacyl chloride to DEDA monomer (Fll-GLA)

[0062] A two-neck 1 L RB flask was fitted with a condenser, magnetic stirrer and a dropping funnel. The reactor was purged with inert gas two times, solid glycine methyl ester hydrochloride (2.1 equiv.) and anhydrous dichloromethane (DCM) (3.0 mL / mmol of methyl ester) were charged into the reactor. The reaction mixture was stirred vigorously at 0-5 °C followed by dropwise addition of Et3N (5 equiv.) to the reaction mixture. After several minutes, the as-prepared 2,5- furandicarbonyl dichloride (1 equiv.) solution in anhydrous DCM (0.5 mL / mmol of diacyl chloride) was added slowly to the reaction mixture over a period of 45 minutes. Finally, the reaction mixture was stirred overnight at room temperature. The insoluble white precipitate was removed by filtration and the solution was dried under rotary evaporator at 45 °C. The crude mixture was re-dissolved in an excess amount of CHCI3 and cooled down to -5 °C. After 1 h, the insoluble precipitate was removed again by filtration and the solution was washed with 3% NaHCOs and distilled water. The organic layer was dried over Na2SC>4, concentrated by a rotary evaporator and dropwise added to excess n-hexane (~ 5-6 times) to yield the target product. Finally, the product was dried under vacuum at 60 °C for several hours. The Fll-GLA product was characterized by1H / 13C NMR, LC-MS, TGA, DSC and elemental analysis.

[0063] Diacyl chloride to DEDA monomer (CY-GLA)

[0064] A two-neck 1 L RB flask was fitted with a condenser, magnetic stirrer and a dropping funnel. The reactor was purged with inert gas two times, solid glycine methyl ester hydrochloride (2.1 equiv.) and anhydrous dichloromethane (DCM) (3.0 mL / mmol of methyl ester) were charged into the reactor. The reaction mixture was stirred vigorously at 0-5 °C followed by dropwise addition of Et3N (5 equiv.) to the reaction mixture. After several minutes, the as-prepared 1 ,4- cyclohexanedicarbonyl dichloride (1 equiv.) solution in anhydrous DCM (0.5 mL / mmol of diacyl chloride) was added slowly to the reaction mixture over a period of 45 minutes. Finally, the reaction mixture was stirred overnight at room temperature. The insoluble white precipitate was removed by filtration and washed repeatedly by distilled water to remove triethylamine hydrochloride salt generated during the reaction. Finally, the product was dried under vacuum at 60 °C for several hours. The CY-GLA product was characterized by1H / 13C NMR, LC-MS, TGA, and DSC.CY-GLA

[0065] Examples 1 to 2: Polyesteramides polymers with different DEDA monomers : Synthesis & properties

[0066] General polymerization procedure of Examples 1 to 2

[0067] The required amount of 1 ,4-cyclohexanedicarboxylic acid (CHDA), 5- sodiosulfoisophthalic acid (SSIA), DEDA, diol, and TyzorOTE (catalyst) were mixed in a glass reactor under atmospheric pressure and N2 gas flow. The polymerization reaction was started by heating the reaction mixture at 160 °C for 1 h under N2 flow, the reaction mixture gradually becomes completely soluble during this period. Next, the reaction temperature raised to 200 °C, N2 flow stopped and vacuum was applied slowly up to 100 mbar. Finally, the temperature was increased in the range of 225-235 °C and gradually vacuum decreased up to 5-10 mbar and the polymerization was continued for another 1-2 h to remove excess of EG and increase the molecular weight (Mw) of PEAs. The final polymer was collected from the glass reactor immediately after the reaction because it is very difficult to collect once cooled down to room temperature.Table 1

[0068] Examples 3 to 7: Polyesteramides polymers with FU-GLA monomers : Synthesis & properties

[0069] Following the protocol of Example 1-2, Examples 3 to 7 with different molar ratios of CHDA, SSIA, FU-GLA and EG were prepared. The characteristics / properties are listed in Table 2 below.Table 2

[0070] The PEAs of Examples 3 to 7 are a very interesting class of water soluble polymers with various functional moieties like hydrophobic, ionic (anionic nature), hydrophilic and heteroaromatic. It is shown by the testing results in Table 2 that a good balance of crystallinity, water-solubility, thermal and mechanical properties, and biodegradability was obtained.

[0071] Gel permeation chromatography (GPC)

[0072] Molecular weight was measured by gel permeation chromatography (GPC) in a WATERS 515 HPLC pump, Shodex-101 Rl detector and two HFIP gel column with guard column with a flow rate of 0.4 ml / min. PMMA is used as standard, PET is used as reference standard and 0.05 M potassium trifluoro acetate in hexafluoroisopropanol (HFIP) as mobile phase.

[0073] Thermogravimetric analysis (TGA)

[0074] TGA was measured in TA instruments (TGA Q500) from room temperature to maximum 800°C with a heating rate of 20 °C / min. The decomposition temperature (Td) mentioned here is the 10% decomposition of initial sample weight.

[0075] Differential scanning calorimetry (DSC)

[0076] The glass transition temperature (Tg) was measured in TA instruments (DSC Q2000) for two cycles of both cooling and heating in the range of -50°C to 200°C with a heating rate of heating rate of 10 °C / min. The reported Tg in the present report have been estimated from the second heating cycle. Tg increased significantly with higher amount of Fll-GLA monomer owing to the incorporation of both amide groups and furan groups. In addition, Tg also increased when SSI A was introduced into thepolymer backbone due to increased aromatic groups. Therefore, by careful variation of monomer units the thermal properties as well as mechanical properties of PEAs can be easily tuned.

[0077] Water solubility test results

[0078] In this test, the polymer obtained by Examples 3-6 (with 5-10 mol% of SSIA) were well soluble in distilled water at least in the range of 1-5 wt%. While the polymer obtained by Example 7 (without SSIA) was not soluble in water.

[0079] Biodegradability test results

[0080] The biodegradability test was done according to OECD (1992), Test No. 302B: Inherent Biodegradability: Zahn-Wellens / EVPA Test, OECD Guidelines for the Testing of Chemicals, Section 3, OECD Publishing, Paris, the content of which is incorporated herein by reference.

[0081] In this test, a mixture containing the test substance, mineral nutrients and a relatively large amount of activated sludge in aqueous medium is agitated and aerated at 20- 25 °C in the dark or in diffuse light for up to 28 days. Blank controls, containing activated sludge and mineral nutrients but no test substance, are run in parallel. The biodegradation process is monitored by determination of DOC (or COD) in filtered samples taken at daily or other time intervals. The ratio of eliminated DOC (or COD), corrected for the blank, after each time interval, to the initial DOC (or COD) value is expressed as the percentage biodegradation at the sampling time. The percentage biodegradation is plotted against time to give the biodegradation curve.

[0082] The water soluble PEAs containing Fll-GLA were tested and inherently biodegradable in the range of 87-98% in 28 days (Table 2). Interestingly, the biodegradability was not affected by the increased amount of amide containing DEDA monomer in the range of 5-20 mol%.

Claims

C L A I M S1. A polyesteramide polymer prepared by polycondensation of at least the following monomers (a) to (d):(a) an aliphatic / aromatic unsulfonated dicarboxylic acid / ester;(b) an aliphatic diol;(c) an aliphatic / aromatic sulfonated dicarboxylic acid / ester; and(d) a compound comprising two ester functions and two amide functions [DEDA],2. The polyesteramide polymer according to claim 1 , wherein the aliphatic / aromatic unsulfonated dicarboxylic acid / ester is selected from:- alkyldicarboxylic acids / esters of formula ROOC-(CH2)n-COOR (I) where n = 2-4 and R is H, a Ci to Cs alkyl or phenyl group;- cyclopentanedicarboxylic acids / alkyl esters or cyclohexanedicarboxylic acids / alkyl esters, in particular 1 ,2-cyclopentanedicarboxylic acid, 1 ,3-cyclopentanedicarboxylic acid, 1 ,3-cyclohexanedicarboxylic acid or 1 ,4-cyclohexanedicarboxylic acid and their corresponding alkyl esters where the alkyl group can vary from methyl to octyl or can be a phenyl group;- terephthalic acid / alkyl esters and isophthalic acid / alkyl esters where the alkyl group can vary from methyl to octyl or can be a phenyl group.

3. The polyesteramide polymer according to claim 1 or 2, wherein the aliphatic / aromatic unsulfonated dicarboxylic acid / ester is an aliphatic one, preferably a cyclohexane derivative, in particular 1 ,4-cyclohexanedicarboxylic acid (CHDA).

4. The polyesteramide polymer according to any one of claims 1 to 3, wherein the aliphatic diol is selected from:- alkyl diols like ethylene glycol or propylene glycol, diethylene glycol, triethylene glycol; a polyethylene glycol having an ethylene oxide number ranging from ranging from 4 to 75;- cyclic saturated diols, preferably cyclopentane diols or cyclohexane diols, in particular 1,2-cyclopentane diol, 1,3-cyclopentane diol, 1,3-cyclohexane diol or 1 ,4- cyclohexane diol.

5. The polyesteramide polymer according to claim 4, wherein the aliphatic diol (b) is an alkyl diol, in particular ethylene glycol (EG).

6. The polyesteramide polymer according to any one of claims 1 to 5, wherein the aliphatic / aromatic sulfonated dicarboxylic acid / ester is selected from:- isophthalic acid / esters, terephthalic acid / esters and naphthalenedicarboxylic acids / esters, in particular 2-sodiosulfoisophthalic acid / esters, 4-sodiosulfoisophthalic acid / esters, 5-sodiosulfoisophthalic acid / esters, 2-sodiosulfoterephthalic acid / esters, 2,6-dicarboxyl naphthalene-4-sodiosulfonic acid / esters and 2,6-dicarboxyl naphthalene-7-sodiosulfonic acid / esters;- dialkyl sodium sulfosuccinates.

7. The polyesteramide polymer according to claim 6, wherein the aliphatic / aromatic sulfonated dicarboxylic acid / ester is an aromatic sulfonated dicarboxylic acid / ester, preferably 5-sodiosulfoisophthalic acid or an ester thereof, in particular 5-sodiosulfoisophthalic acid (SSIA).

8. The polyesteramide polymer according to any of claims 1 to 7, wherein the compound comprising two ester functions and two amide functions [DEDA] is a compound having the general formula (II):wherein:Ri is an arenediyl, an alkanediyl or a cycloalkanediyl;R2 and R3, same or different from each other, are hydrogen, or a straight, branched, cyclic hydrocarbon radical, which is optionally interrupted by one or several heteroatom(s) and / or which is optionally substituted by one or several functional group(s); andR4 and Rs, same or different from each other, are an alkyl.

9. The polyesteramide polymer according to claim 8, wherein the arenediyl is phenylene or furylene.

10. The polyesteramide polymer according to claim 8, wherein the cycloalkanediyl is cyclohexanediyl.

11. The polyesteramide polymer according to claim 8, wherein the alkanediyl is a C1-C20 alkanediyl.

12. The polyesteramide polymer according to any of claims 1 to 11, said polyester being prepared by polycondensation of the following monomers (a) to (d):(a) 1 ,4-cyclohexanedicarboxylic acid (CHDA);(b) ethylene glycol (EG);(c) 5-sodiosulfoisophthalic acid (SSIA);(d) a compound selected from the group consisting of DEDA having the formula (III) (CY-GLA), DEDA having the formula (IV)(FU-GLA) , DEDA having the formula (V)(TE- GLA) and DEDA having the formula (VI)(SU-GLA).

13. The polyesteramide polymer according to claim 12, wherein monomer (d) is DEDA having the formula (IV)(FU-GLA).

14. A polyesteramide polymer comprising the following repeat units: CHDA-EG, SSIA-EG and DEDA-EG (e.g. FU-GLA-EG, CY-GLA-EG, TE-GLA-EG and SU-GLA- EG).

15. A process for synthesizing a polyesteramide polymer according to any of claims 1 to 14, said process comprising a step of polycondensation of monomers (a), (b), (c) and (d) in the presence of a catalyst, preferably a hydrolysis-stable catalyst, more preferably a chelate of a titanium salt or of a zirconium salt derived from ethanol amines, in particular Titanium(IV) (triethanolaminato)isopropoxide.

16. The process according to claim 15, wherein monomers (a), (b), (c) and (d) are first mixed and then reacted by polycondensation by raising temperature and / or reducing pressure.

17. Use of a polyesteramide polymer according to any of claims 1 to 14 or obtained by the process according to claim 15 or 16 as dispersant of active ingredients.

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