A method for producing polymeric particles

Abstract

Disclosed herein are methods for producing polymeric particles from a substantially water-insoluble feedstock polymer, and polymeric particles made according to the method. The method comprising the steps of: providing a polymer solution comprising the feedstock polymer dissolved in a solvent; providing an aqueous phase comprising at least one emulsifier and being at temperature of from about 40 °C to about 95°C; and combining the polymer solution and the aqueous phase under such conditions to produce a mixture comprising the polymeric particles dispersed in the aqueous phase. Also disclosed herein are methods for degradation of waste polymer.

Description

A method for producing polymeric particlesCROSS REFERENCE

[0001] The present application claims priority to Australian Provisional Patent Application no. 2024900597, filed 7 March 2024, the entire contents of which is incorporated herewith by cross reference in its entirety.FIELD OF THE INVENTION

[0002] The invention relates to a method for producing polymeric particles from a substantially water-insoluble feedstock polymer, and polymeric particles made according to the method. It also relates to methods for degradation of waste polymer. However, it will be appreciated that the invention is not limited to this particular field of use.BACKGROUND

[0003] The following discussion of the prior art is provided to place the invention in an appropriate technical context and enable the advantages of it to be more fully understood. It should be appreciated, however, that any discussion of the prior art throughout the specification should not be considered as an express or implied admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0004] It is estimated that the world produces around 300 million tonnes of plastic waste every year, with a total of more than 8.3 billion tonnes of plastic waste estimated to have been produced worldwide since the 1950s. Many of these plastics are estimated to take more than 450 years to decompose in the environment.

[0005] Plastic recycling typically relies on melting waste plastic at high temperatures, which not only can produce toxic gases, but can also interfere with the intrinsic properties of the plastic, e.g. due to processes such as chain scission, thereby limiting the uses for the recycled plastics. In addition, recycling processes that require melting the plastic (e.g. melt extrusion) can be energy intensive.

[0006] Accordingly, there is a need to develop new methods for processing plastic for re-use, in particular waste plastic, without requiring high temperatures and / or having to melt the plastic. There is a further need to develop plastic (e.g. waste plastic) treatment processes that can substantially retain the intrinsic properties of the plastic, thereby allowing more uses for the resultant recycled plastic material.

[0007] There is also a need to develop new composite materials and methods for the production of composite materials from plastics, in particular from waste plastics. Additionally, there is a need to develop methods for increasing the degradation rate of plastics.

[0008] It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.SUMMARY OF THE INVENTION

[0009] The inventors of the present application have surprisingly discovered that the inventive combination of steps and conditions makes it possible to process water-insoluble feedstock polymers (including waste polymers) to form stable aqueous dispersions thereof.

[0010] Although aqueous dispersions of water-insoluble polymers have been formed previously, these have typically required the use of low molecular weight, ultrahydrophobic compound additives having extremely low water solubility (e.g. hexadecane) that act as a plasticiser, and are added to slow Ostwald ripening (the diffusion of molecules in small droplets to larger drops across the continuous phase in an emulsion). However, such additives are difficult to remove, and their use has the disadvantage of affecting the properties (e.g. Young’s modulus) of the resultant polymeric product.

[0011] The inventors of the present invention have surprisingly discovered that these additives are not needed for processing hydrophobic polymers under the inventive conditions, thereby enabling the inventive process to recycle polymers retaining their initial properties (e.g. Young’s modulus).

[0012] The inventive method is capable of colloidally dispersing a variety of different types of waste plastic (e.g. polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS)) in water to obtain waste plastic polymer dispersions. The inventive process may not require grinding or melting of the waste plastic and therefore requires less energy, and may not produce any toxic gases.

[0013] The stable waste plastic polymer dispersions obtained using the inventive method can be directly used as recycled plastics. The waste plastic dispersions can also be fabricated to form robust standalone 3D polymer foams with the improvement in surface area potentially improving the degradation rate of the polymer. In addition, the waste plastic polymer dispersions can be supplemented with fillers such as graphene oxide (GO) or any type of nanoparticles (e.g. spherical, rods, worms, 2D sheets, quantum dots) to form 3D polymer / nanoparticle or 3D polymer / GO nanocomposite foams with tuneable surface, physical, mechanical and / or electricalproperties. The inventive method can be applied in principle to any type of hydrophobic plastic that can be dissolved in a suitable organic solvent.

[0014] In a first aspect of the invention there is provided a method for producing polymeric particles from a substantially water-insoluble feedstock polymer, the method comprising the steps of: providing a polymer solution comprising the feedstock polymer dissolved in a solvent; providing an aqueous phase comprising at least one emulsifier and being at temperature of from about 40 °C to about 95 °C; and combining the polymer solution and the aqueous phase under such conditions to produce a mixture comprising polymeric particles dispersed in the aqueous phase; wherein the mixture comprises less than 0.2 wt.% relative to the total weight of the mixture, or less than 2.5 wt.% of the weight of the polymer phase, of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0015] The following options may be used in conjunction with the first aspect, either individually or in any combination.

[0016] In certain embodiments, the feedstock polymer is a waste polymer. In other words, in certain embodiments the method according to the first aspect is a method for recycling polymeric waste materials.

[0017] In certain embodiments, the mixture comprises less than 0.2, 0.15, 0.1, 0.05, 0.02, 0.01, or 0.005 wt.% relative to the total weight of the mixture of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0018] In certain embodiments, the mixture comprises less than 2.5, 2.2, 2.1, 2, 1.5, 1.2, 1.1, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01, or 0.005 wt.% of the weight of the polymer phase, of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0019] In certain specific embodiments, the mixture does not comprise any hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that aresubstantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0020] In certain embodiments, the feedstock polymer is substantially hydrophobic. The feedstock polymer may have a static water contact angle of greater than about 90°, measured at 1 atm and 20°C at a relative humidity of 40%, or it may be greater than about 95, 100, 105, 110, 115, 120, 125, 130, 140, or 150°, measured at 1 atm and 20°C at a relative humidity of 40%. In certain embodiments, it may have a static water contact angle of about 90, 95, 100, 105, 110, 115, 120, 125, 130, 140, 150, 160 or 170°, measured at 1 atm and 20°C at a relative humidity of 40%.

[0021] In certain embodiments, the feedstock polymer is selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and combinations thereof.

[0022] In certain embodiments, the polymer feedstock is a polyolefin.

[0023] In certain embodiments, the feedstock polymer is selected from the group consisting of low (branched) and high (linear) density polyethylene, polypropylene, poly(propyleneZethylene), other homo- and co-polymers of alpha-olefins including poly (4-methylpentene-l), poly (1- butene), polyisobutylene and higher homologues, poly (ethylene / vinyl acetate), poly(ethylene / maleic anhydride), poly(ethyleneZisobutylene), chlorinated or chlorosulfonated polyethylene, natural rubber (cis-l,4-polyisoprene), chlorinated, oxidized or cyclized rubber, rubber hydro-chloride, gutta percha or balata, (trans-polyisoprene), the corresponding synthetic polyisoprenes, poly(styreneZbutadiene) rubber (SBR), poly(butadieneZacrylonitrile), cis- or trans- 1,4-polybutadiene, poly(isopreneZisobutylene), neoprene, ethyleneZpropyleneZdi-ene terpolymers (EPDM), polystyrene, copolymers of styrene with acrylonitrile, fumaronitrile, 2,5- dichlorostyrene, N-vinylcarbazole, N,N-diphenylacrylamide, divinyl benzene or methyl methacrylate, poly(alpha-methylstyrene), poly(p-tert-butylstyrene), polychlorostyrene, poly(acrylonitrileZbutadieneZstyrene) resin (ABS), coumaroneZindenes, polyterpenes, polymers or copolymers from acrylic, methacrylic, hydroxyalkyl acrylic or methacrylic, cyano acrylic or methacrylic acids or their methyl, ethyl or lauryl esters, polyacrylonitrile, vinyl acetate homopolymer or copolymers with dibutyl fumarate, vinyl stearate, vinyl chloride, 2-ethyl-hexyl acrylate or ethyl acrylate, poly(vinyl butyral), homopolymers of vinyl chloride or vinylidene chloride or copolymers with each other or with diethyl fumarate, diethyl maleate, acrylates or methacrylates, polychlorotrifluoroethylene, polyvinyl or vinylidene fluoride and copolymers with chlorotrifluoroethylene or hexafluoropropylene, synthetic superpolyamides or nylons 6, 6Z6,6Z 10, 11 or 12 or their copolymers, poly (vegetable oil acidZethylene diamine),polyoxymethylene, poly(ethylene oxide), ethylene dihalide / alkali sulfide polysulfide rubbers, cellulose acetate, acetate butyrate, propionate, acetate propionate or nitrate, ethyl cellulose, poly (ethylene terephthalate) or other polyesters of polyhydric alcohols and dicarboxylic acids, polyether, polyester or polyester / polyamide polyurethanes, phosgene / bisphenol A polycarbonates, poly(2,6-dimethyl phenylene oxide), poly(diphenylene sulfone), poly(p- oxybenzoate), poly(phenylene amide), poly(p-phenylenes), poly(xylylenes), aromatic dianhy-dride / aromatic amine polyimides, polybenzimidazole, polybenzo thiazole, polybenzoxazole, poly thiadiazole, polyoxadiazole, polyphenyltriazole, polyphenylsilsesquioxane, silicon / nitrogen, phosphorus / nitrogen or boron / nitrogen inorganic linear polymers, phenol, urea or melamine formaldehyde condensation polymers, styrenated unsaturated polyesters, epoxy resins, polyamines, polyamides, polysulfides, poly dimethylsiloxane or other polysilicones, alkyd resins, diallyl phthalate or ally diglycol carbonate prepolymers, furane resins, phenolic furfural, polyvinyl formal, polyvinyl acetal, and copolymers and combinations thereof. The feedstock polymer is not substantially cross-linked (that is, it is soluble in a suitable organic solvent).

[0024] The solvent may be substantially water immiscible. That is, a mixture of 1:1 by volume of water to the solvent may be biphasic at 1 atm and 20°C. In certain embodiments the solvent may have a water solubility at 1 atm and 20°C of about 1 g / L or less, 500 mg / L or less, or about 400, 300, 200, 100, 50, 40, 30, 20, 10, 5, 2, or 1 mg / L or less. In certain embodiments, the solvent is a substantially water-insoluble and / or hydrophobic organic solvent.

[0025] In certain embodiments, the solvent is selected from the group consisting of ethers; esters; aliphatic, alicyclic, and aromatic hydrocarbons; halogenated derivatives thereof; and mixtures thereof.

[0026] In certain embodiments, the solvent is selected from the group consisting of cyclopentanol, methyl ethyl ketone, methyl isobutyl ketone, dimethylacetamide, secondary butyl methyl ketone, diethyl ketone, ethyl isopropyl ketone, diisopropyl ketone, diethyl ether, secbutyl ether, petroleum ether, ligroin, propyl acetate, butyl and isobutyl acetate, amyl and isoamyl acetate, propyl and isopropyl propionate, ethyl butyrate, pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, methylene chloride, carbon tetrachloride, hexyl chloride, chloroform, ethylene di-chloride, benzene, toluene, xylene, chlorobenzene, and mixtures thereof. In certain specific embodiments, the solvent is selected from the group consisting of xylene, toluene, benzene, chlorobenzene, dichloromethane, chloroform, trifluoroacetic acid, and combinations thereof.

[0027] In certain embodiments, the emulsifier is selected from the group consisting of nonionic, anionic or cationic oil-in-water functioning emulsifying agents. In certain embodiments, the emulsifier is selected from the group consisting of organosulfate salts and organophosphate salts. In certain specific embodiments, the emulsifier comprises sodium dodecyl sulfonate (SDS). Other emulsifiers would be known to the skilled person.

[0028] The conditions to produce the polymeric particles dispersed in the aqueous phase comprises the step of removing the solvent. The solvent may be removed by any number of means known in the art. In certain embodiments, the solvent may be removed by evaporation or distillation. The evaporation may be performed at atmospheric pressure, or at a reduced pressure, for example at a pressure of about 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, or 0.01 kPa or less. In certain embodiments, the solvent may be removed by using a heating step, which may be performed at a temperature of, for example, about 25, 30, 40, 50, 60, 70, 80, 90, or 95 °C.

[0029] The amount of the feedstock polymer in the polymeric particles may be from about 50 wt.% to about 100 wt.%, or about 60 wt.% to about 100 wt.%, about 70 wt.% to about 100 wt.%, about 80 wt.% to about 100 wt.%, about 90 wt.% to about 100 wt.%, about 95 wt.% to about 100 wt.%, about 97 wt.% to about 100wt.%, about 99 wt.% to about 100 wt.%, or about 99.5 wt.% to about 100 wt.%. The amount of the feedstock polymer in the polymeric particles may be about 50, 60, 70, 80, 90, 95, 97, 99, or 99.5 wt.% or more. In certain embodiments, the amount of the feedstock polymer in the polymeric particles is about 95 wt.% or more. In certain specific embodiments, the amount of the feedstock polymer in the polymeric particles is about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 99, 99.5, 99.7, 99.8, 99.9, or 100 wt.%.

[0030] In certain embodiments, the volume:volume ratio of the aqueous phase to the solvent may be from about 20:1 to about 1:1, about 10:1 to about 1:1, about 5:1 to about 1:1, about 15:1 to about 1:1, about 10:1 to about 2:1, about 5:1 to about 2:1, or about 20:1 to about 5:1. It may be about 20:1, 15:1, 10:1, 8:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

[0031] The polymeric particles may have substantially similar properties to the feedstock polymers. For example, they may have a Tgthat is within about ± 1, 2, 3, 4, 5, 10, 20, or 50 °C of, preferably substantially identical to, the Tgof the feedstock polymer. In certain embodiments, the polymeric particles have a Tgthat is within about + 1, 2, 3, 4, or 5 °C of, preferably substantially identical to, the Tgof the feedstock polymer.

[0032] In certain embodiments, the Young's modulus of a bulk material prepared from the polymeric particles may be substantially identical to the Young's modulus of the feedstock polymer, or it may be ± 1, 2, 5, 10, 15, 20, or 25% of the Young's modulus of a bulk materialprepared from the feedstock polymer. In certain embodiments, the Young's modulus of a bulk material prepared from the polymeric particles is at least about 80, 85, 90, 95, or 99 % of, preferably substantially identical to, the Young's modulus of a bulk material prepared from the feedstock polymer. In certain embodiments, the Young’s modulus may be measured according to ASTM D638. In certain embodiments, the bulk materials may be made by heating the feedstock polymer or polymeric particles at a temperature of about or greater than the melting point of said feedstock polymer or polymeric particles in a container to thereby form said bulk materials.

[0033] In certain embodiments, the mixture comprises a homogeneous dispersion of the polymeric particles.

[0034] In certain embodiments, the polymeric particles dispersed in the aqueous phase are in the form of an emulsion. In certain embodiments, the emulsion is an oil-in-water emulsion. In certain specific embodiments, the polymeric particles are not in a water-in-oil emulsion at any step of the method. That is, the method does not include a phase inversion step, for example, from a water-in-oil emulsion to an oil-in-water emulsion.

[0035] The emulsion may be a stable emulsion. In this context, the term “stable emulsion” may mean an emulsion that does not settle into two layers within 1, 2, 4, 8, 12, 18, 24, 48 hours or more when allowed to stand without mixing. Once the emulsion has settled, in certain embodiments stirring with low shear is typically sufficient to restabilise the emulsion.

[0036] In the case where the emulsion is an oil-in-water emulsion it may have an average oil droplet size of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm. It may be, for example, about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm.

[0037] The aqueous phase may be heated to from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, prior to mixing with the polymer solution. In this regard the aqueous phase is added to the polymer solution whilst it is at a temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C. It may, for example, be added at a temperature of about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 °C. In certain embodiments, the aqueous phase is heated to from about 40 °C to about 95 °C prior to mixing with the polymer solution, such that the polymer solution does not substantially precipitate on contact with the aqueous phase. Askilled person will understand that although the first aspect of the invention requires that the temperature of the water should be elevated, in certain alternative embodiments the water may be at a temperature lower than 40 °C, for example 35, 30, 25, or 20 °C, particularly for certain feedstock polymers, such as styrene, where such a lower temperature may be advantageous.

[0038] In certain embodiments, the polymeric particles dispersed in the aqueous phase are formed by mixing at high shear and / or by using sonication. In the case where high shear is used, the polymeric particles (e.g. liquid droplets) dispersed in the aqueous phase may be mixed at a shear rate of from about 0.5 s’1to about 20 s’1, or from about 0.5 s’1to about 15 s’1, about 0.5 s’1to about 10 s’1, about 1 s’1to about 20 s’1, about 2 s’1to about 20 s’1, about 5 s’1to about 20 s’1, about 5 s’1to about 10 s’1, about 2.5 s’1to about 7.5 s’1, or about 4 s’1to about 8 s’1. It may, for example, be mixed at a shear rate of about 0.5, 1, 2, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 s’1.

[0039] The concentration of the polymeric particles suspended in the water phase may be from about 1 wt.% to about 40 wt.%, about 1 wt.% to about 30 wt.%, about 1 wt.% to about 20 wt.%, about 1 wt.% to about 10 wt.%, about 2 wt.% to about 8 wt.%, or about 3 wt.% to about 6 wt.%. It may be, for example, about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 15, 20, 25, 30, 40, 50, 60, 70, or 80 wt.%. In certain embodiments, the concentration of said polymeric particles suspended in said water phase is from about 1 wt.% to about 40 wt.%, preferably from about 2 wt.% to about 10 wt.%, more preferably about 5 wt.%.

[0040] The weight ratio of the solvent to the feedstock polymer is from about 20:1 to about 1:1, about 20:1 to about 2:1, about 20:1 to about 4:1, about 15:1 to about 1: 1, about 10:1 to about 1:1, about 5:1 to about 1:1, about 10: 1 to about 5:1, or about 10:1 to about 2:1. It may be about 20:1, 15:1, 10:1, 8:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1. In certain embodiments, the weight ratio of the solvent to the feedstock polymer is from about 20:1 to about 1:1, preferably from about 10:1 to about 2:1, more preferably about 5:1.

[0041] In certain embodiments, the method does not comprise a phase inversion step.

[0042] In certain embodiments, the polymer solution, aqueous phase, and mixture comprises substantially no monomer, or is entirely absent of monomer. In certain embodiments, the method does not include a polymerisation step.

[0043] In certain embodiments, the method further comprises the step of adding a filler to the aqueous dispersion of polymeric particles. In certain specific embodiments, the filler comprises graphene oxide, quantum dots, nanotubes, worms, and / or a substantially 2D material.

[0044] In certain embodiments, the concentration of filler, e.g. graphene oxide, in the aqueous dispersion is from about 0.01 wt.% to about 30 wt.%, or about 0.02 wt.% to about 30 wt.%,about 0.05 wt.% to about 30 wt.%, about 0.05 wt.% to about 20 wt.%, about 0.05 wt.% to about 10 wt.%, about 0.05 wt.% to about 5 wt.%, about 0.05 wt.% to about 1 wt.%, or about 0.05 wt.% to about 1.5 wt.%. In certain specific embodiments, the concentration of graphene oxide in the aqueous dispersion is from about 0.01 to about 20 wt.%. In certain specific embodiments, the concentration of graphene oxide in the aqueous dispersion is from about 0.05 to about 5 wt.%. The concentration of graphene oxide in the aqueous dispersion may be about 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, or 30 wt.%. In certain specific embodiments, the concentration of graphene oxide in the aqueous dispersion is about 1 wt.%.

[0045] In the case where the filler is graphene oxide, the graphene oxide may be an essentially two dimensional material. The graphene oxide may have a mean aspect ratio of at least about 20, or at least about 50, 100, 200, 500, 1000, 2000, 5000, 104, or 105. It may be from about 20 to about 106, or from about 102to 106, 103to 106, 104to 106, 105to 106, 20 to 105, 20 to 104, 20 to 103, 20 to 102, 102to 103, 103to 104, or 104to 105. It may be for example about 20, 30, 40, 50, 100, 200, 500, 103, 5 x 103, 104, 5 x 104, 105, 5 x 105, or 106. The aspect ratio may be defined as the ratio of the minimum lateral dimension (i.e. in the plane of the graphene oxide) to the average non-lateral dimension (i.e. orthogonal to the plane of the graphene oxide). The graphene oxide may be non-uniform in shape, but on average may have lateral dimension at least 20 times greater than its average non-lateral dimension.

[0046] In the case where the filler is graphene oxide, in certain embodiments, the graphene oxide may have an average lateral dimension of less than about 10,000 nm, 5000 nm, 2000 nm, 1000 nm, 500 nm, 200 nm, 100 nm, 50 nm, 20, or 10 nm. In certain embodiments, an average lateral dimension of the graphene oxide is about 500 nm or less. The graphene oxide may have an average lateral dimension of from about 10 nm to about 10,000 nm, or from about 10 to 500, 20 to 500, 50 to 500, 10 to 20, 20 to 50, 50 to 100, or 10 to 200 nm. It may be for example about 10, 20, 50, 100, 200, 500, or 1000 nm. The graphene oxide may comprise particles formed from a number of sheets of laminar material. The average number of individual sheets in each particle may be 1 or may be greater than about 1, or greater than about 2, 3, 4, 5, 6, 7, 8, 9, or 10 sheets. It may be from about 1 sheet to about 50 sheets, or from about 1 to 20, 1 to 10, or 5 to 50 sheets. It may be for example about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, or 50 sheets.

[0047] In the case where the filler is graphene oxide, in certain embodiments, the graphene oxide may have an average non-lateral dimension (i.e. thickness) of less than about 2000 nm, or less than about 1000, 500, 200, 100, 50, 20, 10, 5, 2, 1, or 0.5 nm. It may be from about 1 to 500, 2 to 500, 5 to 500, 10 to 500, 20 to 500, 0.5 to 200, 0.5 to 100, 0.5 to 50, 0.5 to 20, 2 to 50, 5 to100, or 10 to 200 nm. It may be, for example, about 0.5, 1, 2, 5, 10, 20, 50, 100, 200, 500, or 1000 nm.

[0048] In the case where the filler is graphene oxide, in some embodiments, the carbomoxygen ratio of the graphene oxide may be from about 0.1 to about 5, or about 0.5 to about 5, about 1 to about 4, about 1.5 to about 2.5, or about 2 to about 2.5. It may be, for example, about 0.1, 0.2, 0.5, 1, 1.5, 2, 2.1, 2.2, 2.25, 2.3, 2.35, 2.4, 2.5, 3, 4, or 5. In certain embodiments, the carbomoxygen ratio of the graphene oxide is from about 0.5 to about 5. In certain specific embodiments, the carbomoxygen ratio of the graphene oxide is about 2.25.

[0049] In certain embodiments, the aqueous phase having the polymeric particles dispersed therein is evaporated to thereby provide a substantially dry powder or slurry of said polymeric particles. The evaporation may be performed at atmospheric pressure, or at a reduced pressure, for example at a pressure of about 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, or 0.01 kPa or less. In certain embodiments, the aqueous phase may be removed by using a heating step, which may be performed at a temperature of, for example, about 25, 30, 40, 50, 60, 70, 80, 90, 95, 100, 110, 120 °C, or more.

[0050] The powder may have a particle size distribution D90 of from about 1 pm to about 100 pm, or it may be from about 1 pm to about 50 pm, about 1 pm to about 10 pm, about 10 pm to about 50 pm, about 5 pm to about 50 pm, about 10 pm to about 20 pm, about 5 pm to about 10 pm, or about 5 pm to about 25 pm. It may be, for example, about 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, 50, or 100 pm. The powder may have a particle size distribution D50 of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm. It may be, for example, about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm. The powder may have a particle size distribution Dio of from about 0.1 pm to about 20 pm, or it may be from about 0.1 pm to about 5 pm, about 0.1 pm to about 10 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 3 pm to about 6 pm, about 3 pm to about 10 pm, or about 3 pm to about 20 pm. It may be, for example, about 0.1, 0.5, 1, 1.1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 pm.

[0051] In certain embodiments, the aqueous phase having the polymeric particles dispersed therein is removed under such conditions to form a foam comprising the polymer.

[0052] The aqueous phase may be removed using a freeze drying step to, e.g., form a foam. The freeze-drying may be performed at from about -100°C to about -20 °C, or from about -80°C to about -40°C, or about -100, -80, -60, -50, -40, -30, or -20 °C. The freeze drying may be performed over a period of from about 1 to about 48 hours, or from about 2 to about 24, about 3to about 12, about 4 to about 10, or about 2 to about 5 hours. In certain specific embodiments, the freeze-drying step is conducted under conditions of -60°C temperature, and over a period of from about 2 to about 24 hours. Typically, vacuum levels for freeze drying are between 50mTorr and 300mTorr with lOOmTorr to 200mTorr being the most common range.

[0053] In the case where the aqueous phase having the polymeric particles dispersed therein is removed under conditions to form a foam, the skilled person will understand that the foam may be any shape, morphology, or size, and that its shape, morphology and / or size will depend upon the application. It may have, for example, a spherical structure, cubic structure, cylindrical structure, rectangular structure, tube-like structure, or a wire-like structure.

[0054] In the case where the aqueous phase having the polymeric particles dispersed therein is removed under conditions to form a foam, in some embodiments the foam may have a density of from about 0.001 g / cm3to about 0.4 g / cm3, or it may be from about 0.002 g / cm3to about 0.4 g / cm3, about 0.005 g / cm3to about 0.4 g / cm3, about 0.005 g / cm3to about 0.3 g / cm3, about 0.005 g / cm3to about 0.25 g / cm3, about 0.01 g / cm3to about 0.2 g / cm3, about 0.02 g / cm3to about 0.2 g / cm3, or about 0.1 g / cm3to about 0.2 g / cm3. In certain embodiments, the density of the foam is from about 0.005 g / cm3to about 0.25 g / cm3. The density of the foam may be, for example, about 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3 or 0.4 g / cm3.

[0055] In the case where the aqueous phase having the polymeric particles dispersed therein is removed under conditions to form a foam, in some embodiments the foam may have a porosity of from about 75% to about 99.95%, or from about 80% to about 99.95%, about 90% to about 99.95%, about 90% to about 99.9%, about 95% to about 99.9%, about 80% to about 99.9%, or about 75% to about 95%. In certain embodiments, the porosity of the foam is from about 90 to about 99.95%. The porosity of the foam may be, for example, about 75, 80, 85, 90, 91, 92, 95, 97, 99, 99.5, 99.9, 99.1, 99.2, or 99.95%.

[0056] In the case where the aqueous phase having the polymeric particles dispersed therein is removed under conditions to form a foam, in some embodiments, the pore size of the foam may range from about 10 nm to about 500 pm. In some embodiments, the average pore size is at least about 20 nm, at least about 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, or 500 nm. In some embodiments, the average pore size is at least about 1 pm, 10 pm, 20 pm, 50 pm, 100 pm, 110 pm, 120 pm, 130 pm, 140 pm, 150 pm, 160 pm, 170 pm, 180 pm, 190 pm, 200 pm, 210 pm, or 220 pm. In some embodiments, the average pore size may be about 500 pm or less, 400 pm or less, 300 pm or less, or 250 pm or less. Typically, the foam may have an average pore size from about 100 to about 250 pm, about 110 to about 220 pm, about 120 to about 210 pm, or from about 130 and 200 pm.

[0057] The polymeric particles may have a particle size in the range of from about 10 nm to about 20 microns, about 10 nm to about 10 microns, about 10 nm to about 5 microns, about 10 nm to about 1 micron, about 50 nm to about 20 microns, about 50 nm to about 10 microns, about 50 nm to about 5 microns, about 50 nm to about 1 micron, about 100 nm to about 20 microns, about 100 nm to about 10 microns, about 100 nm to about 5 microns, or about 100 nm to about 1 micron. It may be about 10, 20, 50, 100, 200, or 500 nm, or about 1, 2, 5, 10, or 20 microns. In certain embodiments, the polymeric particles have a particle size in the range of from about 50 nm to about 20 microns.

[0058] The polymeric particles may have a particle size distribution D90 of from about 1 pm to about 100 pm, or it may be from about 1 pm to about 50 pm, about 1 pm to about 10 pm, about 10 pm to about 50 pm, about 5 pm to about 50 pm, about 10 pm to about 20 pm, about 5 pm to about 10 pm, or about 5 pm to about 25 pm. It may be, for example, about 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, 50, or 100 pm. The polymeric particles may have a particle size distribution D50 of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm. It may be, for example, about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm. The polymeric particles may have a particle size distribution Dio of from about 0.1 pm to about 20 pm, or it may be from about 0.1 pm to about 5 pm, about 0.1 pm to about 10 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 3 pm to about 6 pm, about 3 pm to about 10 pm, or about 3 pm to about 20 pm. It may be, for example, about 0.1, 0.5, 1, 1.1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 pm.

[0059] In certain embodiments, the aqueous phase, the solvent and / or the emulsifier are recovered for re-use.

[0060] In certain embodiments, the feedstock polymer is not chemically modified prior to forming said polymer solution. In other words, in such embodiments, the feedstock polymer is not chemically reacted in a manner where its chemical structure or chemical composition is changed prior to forming said polymer solution, optionally at any step of the method. That is, in such embodiments, the chemical structure and composition of the polymeric particle products is substantially the same as the feedstock polymer.

[0061] In certain embodiments, the mixture comprises substantially no water insoluble and non-volatile hydrophobic additives (optionally being components of the mixture other than the emulsifier) having a molecular weight below about 1000 Da. In this context, “non-volatile”means that the additive has a vapour pressure at 20 °C of less than about 1 kPa, or less than 0.5, 0.1, 0.05, or 0.01 kPa.

[0062] In certain embodiments, the method according to the first aspect may enable the separation of different polymers from a mixture of feedstock polymers, optionally by varying the dissolution conditions (e.g. temperature) of the polymer solution prior to combining the polymer solution and the aqueous phase. In certain embodiments, the method further comprises a separation step, whereby the dissolution conditions, such as the temperature of the polymer solution, are varied to thereby enable separation of one or more feedstock polymers (e.g. based on their different solubility properties).

[0063] In a second aspect of the invention there is provided polymeric particles produced according to the method according to the first aspect.

[0064] In a third aspect of the invention there is provided use of the polymeric particles according to the second aspect to produce a composite material (e.g. construction, or coatings), a foam, a membrane (e.g. for water filtration), a material for battery applications, a material for thermal and / or acoustic insulation or absorption, an implantable material for biomedical engineering, additive for asphalt, or an electromagnetic shielding material (e.g. for the defence and / or aviation industry).

[0065] In a fourth aspect of the invention there is provided a method for promoting degradation of a waste polymer, the method comprising the steps of: dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase, removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; and exposing the polymeric particles to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; and wherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0066] The following options may be used in conjunction with the fourth aspect, either individually or in any combination.

[0067] The method of the fourth aspect may incorporate the method according to the first aspect. The method of the first aspect may be incorporated in the method of the fourth aspect.

[0068] The method of the fourth aspect may produce the polymeric particles of the second aspect. The polymeric particles of the second aspect may be formed using the method of the fourth aspect.

[0069] The polymeric particles, aqueous phase, mixture, and polymer solution may be as hereinbefore described with respect to the first aspect. The organic solvent may be the same as the solvent as hereinbefore described with respect to the first aspect. The waste polymer may be the same as the feedstock polymer as hereinbefore described with respect to the first aspect. The surfactant may be the same as the emulsifier as hereinbefore described with respect to the first aspect.

[0070] The water may be at an elevated temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, when it is combined with the polymer solution. A skilled person will understand that although the fourth aspect of the invention requires that the temperature of the water should be elevated, in certain alternative embodiments the water may be at a temperature lower than 40 °C, for example 35, 30, 25, or 20 °C, particularly for certain feedstock polymers, such as styrene, where such a lower temperature may be advantageous.

[0071] Without being bound by theory, the inventors of the present invention postulate that the increased surface area of the polymeric particles as compared with the original waste polymer, enable increased degradation of the polymer under different conditions, such as photodegradation, thermo-oxidative degradation, hydrolytic degradation and / or biodegradation by microorganisms.

[0072] In a fifth aspect of the invention there is provided a method for promoting degradation of a waste polymer, the method comprising the steps of: dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase,removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; removing the aqueous phase under such conditions to produce a foam comprising the waste polymer; and exposing the foam to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; and wherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

[0073] The following options may be used in conjunction with the fifth aspect, either individually or in any combination.

[0074] The term “promoting degradation” in the context of the fourth and fifth aspects, means that the rate of degradation of the polymeric particles produced from a waste polymer according to the inventive method is greater than the rate of degradation of the same waste polymer which has not been subjected to the inventive method.

[0075] The polymeric particles, aqueous phase, mixture, foam, and polymer solution may be as hereinbefore described with respect to the first aspect. The organic solvent may be the same as the solvent as hereinbefore described with respect to the first aspect. The waste polymer may be the same as the feedstock polymer as hereinbefore described with respect to the first aspect. The surfactant may be the same as the emulsifier as hereinbefore described with respect to the first aspect.

[0076] The water may be at an elevated temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, when it is combined with the polymer solution. A skilled person will understand that although the fifth aspect of the invention requires that the temperature of the water should be elevated, in certain alternative embodiments the water may be at a temperature lower than 40 °C, for example 35, 30, 25, or 20 °C, particularly for certain feedstock polymers, such as styrene, where such a lower temperature may be advantageous.

[0077] In certain embodiments, the foam is an aerogel. In certain embodiments, the foam comprises one or more radical producing species. In certain embodiments, the one or more radical producing species generate radicals upon irradiation with electromagnetic radiation (e.g. visible light, UV, and / or NIR radiation). In certain embodiments, the one or more radical producing species comprise graphene oxide. The graphene oxide may be as hereinbefore described with respect to the first aspect.

[0078] In certain embodiments, the conditions capable of degrading the waste polymer are such that the waste polymer is degraded by one or more processes selected from the group consisting of photodegradation, thermo-oxidative degradation, hydrolytic degradation and biodegradation by microorganisms.

[0079] Without being bound by theory, the inventors of the present invention postulate that the increased surface area of the foam product, as compared with the original waste polymer, enable increased degradation of the polymer under different conditions, such as photodegradation, thermo-oxidative degradation, hydrolytic degradation and / or biodegradation by microorganisms. Further, the incorporation of agents which can increase degradation, such as radical producing species (e.g. graphene oxide), may further increase the rate of degradation of the polymer.

[0080] The method of the fifth aspect may incorporate the method according to the first aspect. The method of the first aspect may be incorporated in the method of the fifth aspect.

[0081] The method of the fifth aspect may produce the polymeric particles of the second aspect. The polymeric particles of the second aspect may be formed using the method of the fifth aspect.BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 shows a variety of example feedstock polymers that can be processed using the inventive method: a) LDPE plastic bag; b) LDPE disposable pipette; c) PP bottle cap; d) PET cup; e) dirty PP lunch box lid; f) virgin PP pellets; g) virgin PET pellets; h) virgin PDPE pellets; and i) PVC waste pipes.

[0083] Figure 2 shows miniemulsions formed according to the inventive method: A) plastic waste miniemulsion latex; B) plastic waste miniemulsion latex with GO.

[0084] Figure 3 shows foams and powders formed according to the inventive method: A) plastic waste foam (HDPE); B) plastic waste / GO foam; C) plastic waste powder (PET).

[0085] Figure 4 shows examples of Dynamic Light Scattering (DLS) data for oil droplet sizes of organic solvent containing dissolved polymer dispersed in water formed according to the inventive method: A) HDPE; B) LDPE.

[0086] Figure 5 shows stress-strain data of a statistical copolymer of styrene and n-butyl acrylate (50:50 wt:wt) with 5 wt% hexadecane (relative to polymer; blue, A) and without hexadecane (yellow, B).DEFINITIONS

[0087] In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting.

[0088] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.

[0089] Unless the context clearly requires otherwise, throughout the description and the claims, the terms “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. For example, a composition, mixture, process or method that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, mixture, process or method.

[0090] The transitional phrase “consisting of’ excludes any element, step, or ingredient not specified. If in the claim, such would close the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase “consisting of’ appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0091] The transitional phrase “consisting essentially of’ is used to define a composition, process or method that includes materials, steps, features, components, or elements, in addition to those literally disclosed, provided that these additional materials, steps, features, components, or elements do not materially affect the basic and novel characteristic(s) of the claimed invention. The term “consisting essentially of’ occupies a middle ground between “comprising” and “consisting of’.

[0092] Where applicants have defined an invention or a portion thereof with an open-ended term such as “comprising”, it should be readily understood that (unless otherwise stated) the description should be interpreted to also describe such an invention using the terms “consisting essentially of’ or “consisting of’. In other words, with respect to the terms “comprising”,“consisting of’, and “consisting essentially of’, where one of these three terms is used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms. Thus, in some embodiments not otherwise explicitly recited, any instance of “comprising” may be replaced by “consisting of’ or, alternatively, by “consisting essentially of’.

[0093] Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term “about”. The examples are not intended to limit the scope of the invention. In what follows, or where otherwise indicated, “%” will mean “weight %”, “ratio” will mean “weight ratio” and “parts” will mean “weight parts”.

[0094] The terms “predominantly”, “predominant”, and “substantially” as used herein shall mean comprising more than 50% by weight, unless otherwise indicated.

[0095] As used herein, with reference to numbers in a range of numerals, the terms “about,” “approximately” and “substantially” are understood to refer to the range of -10% to +10% of the referenced number, preferably -5% to +5% of the referenced number, more preferably -1 % to + 1 % of the referenced number, most preferably -0.1 % to +0.1 % of the referenced number. Moreover, with reference to numerical ranges, these terms should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, from 8 to 10, and so forth.

[0096] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0097] As used herein, the term “polymeric particles” means distinct particles that predominantly comprise polymeric material and that have a mean diameter of less than about 100, 50, or 10 pm. The polymeric particles may be solid particles, or they may be liquid particles (e.g. droplets in an emulsion).

[0098] As used herein, the term “substantially water-insoluble” or “water insoluble” with respect to a material means that the material has a solubility in water at 1 atm and 20°C of less than about 50 mg / L, 10 mg / L, 5 mg / L, 1 mg / L, or 0.5 mg / L.

[0099] As used herein, the term “emulsifier” means a substance that stabilises an emulsion, or a substance that encourages the suspension of one liquid in another.[000100] As used herein, the term “substantially hydrophobic” or “hydrophobic” means a substance that has a static water contact angle of greater than about 90°, measured at 1 atm and 20°C at a relative humidity of 40%, and / or that is substantially water-insoluble.[000101] As used herein, the term “homogeneously dispersed” with respect to particles homogeneously dispersed in a phase, means than any sample comprising 10% of the volume of the phase will contain substantially the same number of particles ±20%, +10%, or +5% as any other sample comprising 10% of the volume of the phase. In other words, if the phase is divided into 10 samples of equal volume, the number of particles in each of the samples will be the substantially the same, within +20%, +10%, or +5%.[000102] As used herein, the term “aerogel” means a porous material derived from a gel, in which a liquid component of the gel has been replaced with a gas without significant collapse of the gel structure.[000103] As used herein, the term “lateral dimension” with respect to graphene oxide refers to the average width and length of a graphene oxide sheet in the plane of the sheet. That is, a dimension that is orthogonal to the sheet thickness.ABBREVIATIONS[000104] ABS: poly(acrylonitrile / butadiene / styrene) resin; DCM: dichloromethane; EPDM: ethylene / propylene / diene terpolymers; GO: graphene oxide; HDPE: high density polyethylene; LDPE: low density polyethylene; NIR: near infrared; PET: polyethylene terephthalate; PP: polypropylene; PS: polystyrene; PVC: polyvinylchloride; SBR: poly(styrene / butadiene) rubber; SDS: sodium dodecyl sulfonate; TFA: trifluoroacetic acid; Tg: glass transition temperature;THF: tetrahydrofuran; UV: ultraviolet.[000105] Preferred features, embodiments and variations of the invention may be discerned from the following Examples which provides sufficient information for those skilled in the art to perform the invention. The following Examples are not to be regarded as limiting the scope of the preceding Summary of the Invention in any way.EXAMPLES[000106] The inventive method is capable of processing a variety of virgin and waste plastics, including those shown in Figure 1.Example 1: Experimental procedures for LDPE, HDPE, and PP feedstock polymers[000107] The (waste) feedstock polymer was cut into small pieces and placed in a vial. Organic solvent (p-xylene) ([solvent:plastic][5:l])(wt:wt) was poured into the vial. The vial was placed inan oil bath. The feedstock polymer was dissolved in the solvent under constant stirring at the following conditions:• Low Density Polyethylene (LDPE): 150 °C for 20 min• High Density Polyethylene (HDPE): 150 °C for 20 min• *Polyproplylene (PP): 170 °C for 20 min*The dissolution temperature for PP could be reduced to 150 °C, however this resulted in the time it takes for the PP to dissolve being slightly longer.[000108] Once the polymer was completely dissolved in the solvent, water and surfactant (SDS) were immediately added to the vial at a temperature of from about 40 ° C to about 950C whilst the mixture was constantly stirred. The resulting oil- water mixture was subjected to shear force (ultrasonication) for 10 min to homogenize it (resulting in the formation of oil droplets). Figure 4 shows some example DLS data for organic solvent containing dissolved polymer droplets dispersed in water.[000109] The emulsion was constantly stirred at room temperature with moderate speed to remove the organic solvent, resulting in an emulsion of polymeric particles in water (e.g. as shown in Figure 2A). Alternatively, GO could be added with the water and surfactant, resulting in an emulsion of polymeric particles and GO in water (e.g. as shown in Figure 2B).[000110] Finally, the emulsion was prepared for lyophilization to obtain a foam (e.g. as shown in Figure 3 A and 3B) or alternatively the emulsion could be dried at e.g. room temperature to form a film or powder (e.g. as shown in Figure 3C).Example 2: Experimental procedure for PET feedstock polymer[000111] The (waste) feedstock polymer was cut into small pieces and placed in a vial. A mixture of trifluoroacetic acid (TFA) and dichloromethane (DCM) ([TFA:DCM][l:2](v / v)) was poured into the vial ([solvent:plastic][5:l])(wt / wt). The vial was placed in an oil bath. The feedstock polymer was dissolved in the solvent under constant stirring at 40 °C for 30 min.[000112] Once the polymer was completely dissolved in the solvent, water and surfactant (SDS) at a temperature of from about 400C to about 950C were immediately added to the vial whilst the mixture was constantly stirred. The resulting oil- water mixture was subjected to shear force (ultrasonication) for 10 min to homogenize it (resulting in the formation of oil droplets).[000113] The emulsion was constantly stirred at room temperature with moderate speed to remove the solvent. Finally, the emulsion was prepared for lyophilization or drying to obtain a foam, film, or powder.Example 3: Comparison of polymer properties formed from a non-inventive process and the inventive process[000114] As discussed earlier, previous studies have used the addition of an additive compound to enhance emulsion stability when making an initial emulsion. The amount of the additive compound is typically a few wt.% relative to the polymer.[000115] These additive compounds may be described as hydrocarbons and hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters which are inert, nonvolatile, water insoluble, liquid and contain a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms. Typical examples include cetyl alcohol and hexadecane.[000116] These compounds cannot easily be removed from the final polymer product, i.e. the final polymer product contains a few wt.% of this impurity. These compounds function as plasticizers, i.e. their presence leads to a reduction in the glass transition temperature (Tg), resulting in a much softer (much lower Young’s modulus) material.[000117] Figure 5 illustrates this point for a copolymer of styrene and n-butyl acrylate (Young’s modulus is the initial slope in Fig 5) formed using a non-inventive method incorporating 5 wt% hexadecane (relative to polymer; Figure 5 : a) as compared with the inventive method without hexadecane (Figure 5: b).[000118] If the initial polymer is semicrystalline (or crystalline), the incorporation of low molecular weight species such as hexadecane and cetyl alcohol reduces the level of crystallinity, and thereby also dramatically alter the physical properties of the material (e.g. lower Young’s modulus, resulting in a softer and more rubber-like material).[000119] Other embodiments of the invention as described herein are defined in the following paragraphs:1. A method for producing polymeric particles from a substantially water- insoluble feedstock polymer, the method comprising the steps of: providing a polymer solution comprising the feedstock polymer dissolved in a solvent; providing an aqueous phase comprising at least one emulsifier and being at temperature of from about 40 °C to about 95 °C; and combining the polymer solution and the aqueous phase under such conditions to produce a mixture comprising the polymeric particles dispersed in the aqueous phase; wherein the mixture comprises less than 0.2 wt.% relative to the total weight of the mixture, or less than 2.5 wt.% of the weight of the polymer phase, of hydrocarbons, hydrocarbyl alcohols,ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms; optionally, the mixture comprises less than 2.5, 2.2, 2.1, 2, 1.5, 1.2, 1.1, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01, or 0.005 wt.% of the weight of the polymer phase, of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms; optionally, the mixture does not comprise any hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms; optionally, the volume: volume ratio of the aqueous phase to the solvent may be from about 20:1 to about 1:1, about 10:1 to about 1:1, about 5:1 to about 1:1, about 15:1 to about 1:1, about 10:1 to about 2:1, about 5:1 to about 2:1, or about 20:1 to about 5:1. It may be about 20:1, 15:1, 10:1, 8:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1; optionally, the mixture comprises a homogeneous dispersion of the polymeric particles.2. The method according to any one or more of the preceding paragraphs, wherein the feedstock polymer is a waste polymer.3. The method according to any one or more of the preceding paragraphs, wherein the feedstock polymer is substantially hydrophobic; optionally the feedstock polymer may have a static water contact angle of greater than about 90°, measured at 1 atm and 20°C at a relative humidity of 40%, or it may be greater than about 95, 100, 105, 110, 115, 120, 125, 130, 140, or 150°, measured at 1 atm and 20°C at a relative humidity of 40%, or it may have a static water contact angle of about 90, 95, 100, 105, 110, 115, 120, 125, 130, 140, 150, 160 or 170°, measured at 1 atm and 20°C at a relative humidity of 40%.4. The method according to any one or more of the preceding paragraphs, wherein the feedstock polymer is selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and combinations thereof.5. The method according to any one or more of the preceding paragraphs, wherein the polymer feedstock is a polyolefin.6. The method according to any one or more of the preceding paragraphs, wherein the feedstock polymer is selected from the group consisting of low (branched) and high (linear) density polyethylene, polypropylene, poly(propylene / ethylene), other homo- and co-polymers of alpha-olefins including poly (4-methylpentene-l ), poly (1 -butene), polyisobutylene and higherhomologs, poly (ethylene / vinyl acetate), poly(ethylene / maleic anhydride), poly(ethyleneZisobutylene), chlorinated or chlorosulfonated polyethylene, natural rubber (cis- 1,4- polyisoprene), chlorinated, oxidized or cyclized rubber, rubber hydro-chloride, gutta percha or balata, (trans-polyisoprene), the corresponding synthetic polyisoprenes, poly(styrene / butadiene) rubber (SBR), poly(butadiene / acrylonitrile), cis- or trans- 1 ,4-polybutadiene, poly(isopreneZisobutylene), neoprene, ethyleneZpropyleneZdi-ene terpolymers (EPDM), polystyrene, copolymers of styrene with acrylonitrile, fumaronitrile, 2,5-dichlorostyrene, N- vinylcarbazole, N,N-diphenylacrylamide, divinyl benzene or methyl methacrylate, poly(alpha-methylstyrene), poly(p-tert-butylstyrene), polychlorostyrene, poly(acrylonitrileZbutadieneZstyrene) resin (ABS), coumaroneZindenes, polyterpenes, polymers or copolymers from acrylic, methacrylic, hydroxyalkyl acrylic or methacrylic, cyano acrylic or methacrylic acids or their methyl, ethyl or lauryl esters, polyacrylonitrile, vinyl acetate homopolymer or copolymers with dibutyl fumarate, vinyl stearate, vinyl chloride, 2-ethyl-hexyl acrylate or ethyl acrylate, poly(vinyl butyral), homopolymers of vinyl chloride or vinylidene chloride or copolymers with each other or with diethyl fumarate, diethyl maleate, acrylates or methacrylates, polychlorotrifluoroethylene, polyvinyl or vinylidene fluoride and copolymers with chlorotrifluoroethylene or hexafluoropropylene, synthetic superpolyamides or nylons 6, 6Z6,6Z 10, 11 or 12 or their copolymers, poly (vegetable oil acidZethylene diamine), polyoxymethylene, poly(ethylene oxide), ethylene dihalideZalkali sulfide polysulfide rubbers, cellulose acetate, acetate butyrate, propionate, acetate propionate or nitrate, ethyl cellulose, poly(ethylene terephthalate) or other polyesters of polyhydric alcohols and dicarboxylic acids, polyether, polyester or polyesterZpolyamide polyurethanes, phosgeneZbisphenol A polycarbonates, poly(2,6-dimethyl phenylene oxide), poly(diphenylene sulfone), poly(p- oxybenzoate), poly(phenylene amide), poly(p-phenylenes), poly(xylylenes), aromatic dianhy-drideZaromatic amine polyimides, polybenzimidazole, polybenzo thiazole, polybenzoxazole, poly thiadiazole, polyoxadiazole, polyphenyltriazole, polyphenylsilsesquioxane, siliconZnitrogen, phosphorusZnitrogen or boronZnitrogen inorganic linear polymers, phenol, urea or melamine formaldehyde condensation polymers, styrenated unsaturated polyesters, epoxy resins, polyamines, polyamides, polysulfides, poly dimethylsiloxane or other polysilicones, alkyd resins, diallyl phthalate or ally diglycol carbonate prepolymers, furane resins, phenolic furfural, polyvinyl formal, polyvinyl acetal, and copolymers and combinations thereof.7. The method according to any one or more of the preceding paragraphs, wherein the solvent is a substantially water-insoluble andZor hydrophobic organic solvent; optionally, the solvent may be substantially water immiscible, or may have a water solubility at 1 atm and 20°Cof about 1 g / L or less, 500 mg / L or less, or about 400, 300, 200, 100, 50, 40, 30, 20, 10, 5, 2, or 1 mg / L or less.8. The method according to any one or more of the preceding paragraphs, wherein the solvent is selected from the group consisting of ethers; esters; aliphatic, alicyclic, and aromatic hydrocarbons; halogenated derivatives thereof; and mixtures thereof.9. The method according to any one or more of the preceding paragraphs, wherein the solvent is selected from the group consisting of cyclopentanol, methyl ethyl ketone, methyl isobutyl ketone, secondary butyl methyl ketone, diethyl ketone, ethyl isopropyl ketone, diisopropyl ketone, diethyl ether, sec-butyl ether, petroleum ether, ligroin, propyl acetate, butyl and isobutyl acetate, amyl and isoamyl acetate, propyl and isopropyl propionate, ethyl butyrate, pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, methylene chloride, carbon tetrachloride, hexyl chloride, chloroform, ethylene di-chloride, benzene, toluene, xylene, chlorobenzene, and mixtures thereof.10. The method according to any one or more of the preceding paragraphs, wherein the solvent is selected from the group consisting of xylene, toluene, benzene, chlorobenzene, dichloromethane, chloroform, trifluoroacetic acid, and combinations thereof.11. The method according to any one or more of the preceding paragraphs, wherein the emulsifier is selected from the group consisting of non-ionic, anionic or cationic oil-in-water functioning emulsifying agents; optionally, the emulsifier is selected from the group consisting of organosulfate salts and organophosphate salts.12. The method according to any one or more of the preceding paragraphs, wherein the emulsifier comprises sodium dodecyl sulfonate (SDS).13. The method according to any one or more of the preceding paragraphs, wherein the conditions to produce the polymeric particles dispersed in the aqueous phase comprises the step of removing the solvent, preferably by evaporation or distillation; optionally the evaporation may be performed at atmospheric pressure, or at a reduced pressure, for example at a pressure of about 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, or 0.01 kPa or less; optionally, the solvent may be removed by using a heating step, which may be performed at a temperature of, for example, about 25, 30, 40, 50, 60, 70, 80, 90, or 95 °C.14. The method according to any one or more of the preceding paragraphs, wherein the amount of the feedstock polymer in the polymeric particles is about 95 wt.% or more, or from about 50 wt.% to about 100 wt.%, or about 60 wt.% to about 100 wt.%, about 70 wt.% to about 100 wt.%, about 80 wt.% to about 100 wt.%, about 90 wt.% to about 100 wt.%, about 95 wt.% toabout 100 wt.%, about 97 wt.% to about 100wt.%, about 99 wt.% to about 100 wt.%, or about99.5 wt.% to about 100 wt.%, or about 50, 60, 70, 80, 90, 95, 97, 99, or 99.5 wt.% or more, or about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 99, 99.5, 99.7, 99.8, 99.9, or 100 wt.%.15. The method according to any one or more of the preceding paragraphs, wherein the polymeric particles have a Tgthat is within about ± 1, 2, 3, 4, or 5 °C, or 10, 20, or 50 °C of, preferably substantially identical to, the Tgof the feedstock polymer; optionally, the polymeric particles have a Tgthat is within about ± 1, 2, 3, 4, or 5 °C of, preferably substantially identical to, the Tgof the feedstock polymer.16. The method according to any one or more of the preceding paragraphs, wherein the Young's modulus of a bulk material made from the polymeric particles is at least about 80, 85, 90, 95, or 99 % of, preferably substantially identical to, the Young's modulus of a substantially similar bulk material made from the feedstock polymer; optionally it may be ± 1, 2, 5, 10, 15, 20, or 25% of the Young's modulus of a bulk material prepared from the feedstock polymer; optionally the Young's modulus of a bulk material prepared from the polymeric particles is at least about 80, 85, 90, 95, or 99 % of, preferably substantially identical to, the Young's modulus of a bulk material prepared from the feedstock polymer; optionally, the Young’s modulus may be measured according to ASTM D638; optionally, the bulk materials may be made by heating the feedstock polymer or polymeric particles at a temperature of about or greater than the melting point of said feedstock polymer or polymeric particles in a container to thereby form said bulk materials17. The method according to any one or more of the preceding paragraphs, wherein the polymeric particles dispersed in the aqueous phase are in the form of an emulsion; optionally, the emulsion is an oil-in-water emulsion; optionally, the polymeric particles are not in a water-in-oil emulsion at any step of the method; optionally, the method does not include a phase inversion step, for example, from a water-in-oil emulsion to an oil-in-water emulsion; optionally, the emulsion may be a stable emulsion; optionally the emulsion is an oil-in-water emulsion having an average oil droplet size of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm, or about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm.18. The method according to any one or more of the preceding paragraphs, wherein the aqueous phase is heated to from about 40 °C to about 95 °C prior to mixing with the polymer solution, such that the polymer solution does not substantially precipitate on contact with the aqueous phase; optionally, the aqueous phase may be heated to from about 40 °C to about 95 °C,about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, prior to mixing with the polymer solution; optionally the aqueous phase is added to the polymer solution whilst it is at a temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, or at a temperature of about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 °C; optionally, the aqueous phase is heated to from about 40 °C to about 95 °C prior to mixing with the polymer solution, such that the polymer solution does not substantially precipitate on contact with the aqueous phase.19. The method according to any one or more of the preceding paragraphs, wherein the polymeric particles dispersed in the aqueous phase are formed by mixing at high shear and / or by using sonication; optionally where high shear is used, the polymeric particles (e.g. liquid droplets) dispersed in the aqueous phase may be mixed at a shear rate of from about 0.5 s’1to about 20 s-1, or from about 0.5 s1to about 15 s-1, about 0.5 s1to about 10 s-1, about 1 s1to about 20 s’1, about 2 s’1to about 20 s’1, about 5 s’1to about 20 s’1, about 5 s’1to about 10 s’1, about 2.5 s’1to about 7.5 s’1, or about 4 s’1to about 8 s’1, or about 0.5, 1, 2, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 s’1.20. The method according to any one or more of the preceding paragraphs, wherein the concentration of said polymeric particles suspended in said water phase is from about 1 wt.% to about 40 wt.%, preferably from about 2 wt.% to about 10 wt.%, more preferably about 5 wt.%; optionally, the concentration of the polymeric particles suspended in the water phase may be from about 1 wt.% to about 40 wt.%, about 1 wt.% to about 30 wt.%, about 1 wt.% to about 20 wt.%, about 1 wt.% to about 10 wt.%, about 2 wt.% to about 8 wt.%, or about 3 wt.% to about 6 wt.%, or about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 15, 20, 25, 30, 40, 50, 60, 70, or 80 wt.%.21. The method according to any one or more of the preceding paragraphs, wherein the weight ratio of the solvent to the feedstock polymer is from about 20:1 to about 1:1, preferably from about 10:1 to about 2:1, more preferably about 5:1; optionally, the weight ratio of the solvent to the feedstock polymer is from about 20:1 to about 1:1, about 20:1 to about 2:1, about 20:1 to about 4:1, about 15:1 to about 1:1, about 10:1 to about 1:1, about 5:1 to about 1:1, about 10:1 to about 5:1, or about 10:1 to about 2:1, or about 20:1, 15:1, 10:1, 8:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.22. The method according to any one or more of the preceding paragraphs, which does not comprise a phase inversion step.23. The method according to any one or more of the preceding paragraphs, wherein the method further comprises the step of adding a filler to the aqueous dispersion of polymeric particles; optionally the filler comprises graphene oxide, quantum dots, nanotubes, worms, and / or a substantially 2D material; optionally the concentration of filler, e.g. graphene oxide, in the aqueous dispersion is from about 0.01 wt.% to about 30 wt.%, or about 0.02 wt.% to about 30 wt.%, about 0.05 wt.% to about 30 wt.%, about 0.05 wt.% to about 20 wt.%, about 0.05 wt.% to about 10 wt.%, about 0.05 wt.% to about 5 wt.%, about 0.05 wt.% to about 1 wt.%, or about 0.05 wt.% to about 1.5 wt.%.24. The method according to any one or more of the preceding paragraphs, wherein the filler is graphene oxide; optionally, the concentration of graphene oxide in the aqueous dispersion is from about 0.01 to about 20 wt.%, or from about 0.05 to about 5 wt.%, or about 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, or 30 wt.%; optionally the graphene oxide may be an essentially two dimensional material, and optionally may have a mean aspect ratio of at least about 20, or at least about 50, 100, 200, 500, 1000, 2000, 5000, 104, or 105, or from about 20 to about 106, or from about 102to 106, 103to 106, 104to 106, 105to 106, 20 to 105, 20 to 104, 20 to 103, 20 to 102, 102to 103, 103to 104, or 104to 105, or about 20, 30, 40, 50, 100, 200, 500, 103, 5 x 103, 104, 5 x 104, 105, 5 x 105, or 106; optionally, the graphene oxide may be non-uniform in shape, but on average may have lateral dimension at least 20 times greater than its average non-lateral dimension; optionally, in the case where the filler is graphene oxide, the graphene oxide may have an average lateral dimension of less than about 10,000 nm, 5000 nm, 2000 nm, 1000 nm, 500 nm, 200 nm, 100 nm, 50 nm, 20, or 10 nm; optionally the graphene oxide may have an average lateral dimension of from about 10 nm to about 10,000 nm, or from about 10 to 500, 20 to 500, 50 to 500, 10 to 20, 20 to 50, 50 to 100, or 10 to 200 nm, or about 10, 20, 50, 100, 200, 500, or 1000 nm; optionally, the graphene oxide may comprise particles formed from a number of sheets of laminar material; optionally, the average number of individual sheets in each particle may be1 or may be greater than about 1, or greater than about 2, 3, 4, 5, 6, 7, 8, 9, or 10 sheets, or from about 1 sheet to about 50 sheets, or from about 1 to 20, 1 to 10, or 5 to 50 sheets, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, or 50 sheets; optionally, the graphene oxide may have an average non-lateral dimension (i.e. thickness) of less than about 2000 nm, or less than about 1000, 500, 200, 100, 50, 20, 10, 5, 2, 1, or 0.5 nm, or from about 1 to 500, 2 to 500, 5 to 500, 10 to 500, 20 to 500, 0.5 to 200, 0.5 to 100, 0.5 to 50, 0.5 to 20, 2 to 50, 5 to 100, or 10 to 200 nm, or about 0.5, 1, 2, 5, 10, 20, 50, 100, 200, 500, or 1000 nm; optionally, the carbomoxygen ratioof the graphene oxide may be from about 0.1 to about 5, or about 0.5 to about 5, about 1 to about 4, about 1.5 to about 2.5, or about 2 to about 2.5, or about 0.1, 0.2, 0.5, 1, 1.5, 2, 2.1, 2.2, 2.25, 2.3, 2.35, 2.4, 2.5, 3, 4, or 5.25. The method according to any one or more of the preceding paragraphs, wherein the aqueous phase having the polymeric particles dispersed therein is evaporated or distilled to thereby provide a substantially dry powder or slurry of said polymeric particles; optionally, the evaporation may be performed at atmospheric pressure, or at a reduced pressure, for example at a pressure of about 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, or 0.01 kPa or less; optionally, the aqueous phase may be removed by using a heating step, which may be performed at a temperature of, for example, about 25, 30, 40, 50, 60, 70, 80, 90, 95, 100, 110, 120 °C, or more; optionally, the powder may have a particle size distribution D90 of from about 1 m to about 100 pm, or it may be from about 1 pm to about 50 pm, about 1 pm to about 10 pm, about 10 pm to about 50 pm, about 5 pm to about 50 pm, about 10 pm to about 20 pm, about 5 pm to about 10 pm, or about 5 pm to about 25 pm, or about 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, 50, or 100 pm; optionally, the powder may have a particle size distribution D50 of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm, or about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm; optionally, the powder may have a particle size distribution Dio of from about 0.1 pm to about 20 pm, or it may be from about 0.1 pm to about 5 pm, about 0.1 pm to about 10 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm, about 3 pm to about 6 pm, about 3 pm to about 10 pm, or about 3 pm to about 20 pm, or about 0.1, 0.5, 1, 1.1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 pm.26. The method according to any one or more of the preceding paragraphs, wherein the aqueous phase having the polymeric particles dispersed therein is removed under such conditions to form a foam comprising the polymer; optionally the aqueous phase may be removed using a freeze drying step to, e.g., form a foam; optionally, the freeze-drying may be performed at from about -100°C to about -20 °C, or from about -80°C to about -40°C, or about -100, -80, -60, -50, - 40, -30, or -20 °C; optionally, the freeze drying may be performed over a period of from about 1 to about 48 hours, or from about 2 to about 24, about 3 to about 12, about 4 to about 10, or about 2 to about 5 hours; optionally, the freeze-drying step is conducted under conditions of -60°C temperature, and over a period of from about 2 to about 24 hours; optionally, the foam has a spherical structure, cubic structure, cylindrical structure, rectangular structure, tube-like structure, or a wire-like structure; optionally the foam may have a density of from about 0.001g / cm3to about 0.4 g / cm3, or it may be from about 0.002 g / cm3to about 0.4 g / cm3, about 0.005 g / cm3to about 0.4 g / cm3, about 0.005 g / cm3to about 0.3 g / cm3, about 0.005 g / cm3to about 0.25 g / cm3, about 0.01 g / cm3to about 0.2 g / cm3, about 0.02 g / cm3to about 0.2 g / cm3, or about 0.1 g / cm3to about 0.2 g / cm3, or from about 0.005 g / cm3to about 0.25 g / cm3, or about 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.3 or 0.4 g / cm3; optionally, the foam may have a porosity of from about 75% to about 99.95%, or from about 80% to about 99.95%, about 90% to about 99.95%, about 90% to about 99.9%, about 95% to about 99.9%, about 80% to about 99.9%, or about 75% to about 95%, or from about 90 to about 99.95%, or about 75, 80, 85, 90, 91, 92, 95, 97, 99, 99.5, 99.9, 99.1, 99.2, or 99.95%; optionally, the pore size of the foam may range from about 10 nm to about 500 pm; optionally, the average pore size is at least about 20 nm, at least about 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, or 500 nm, or the average pore size is at least about 1 pm, 10 pm, 20 pm, 50 pm, 100 pm, 110 pm, 120 pm, 130 pm, 140 pm, 150 pm, 160 pm, 170 pm, 180 pm, 190 pm, 200 pm, 210 pm, or 220 pm, or the average pore size may be about 500 pm or less, 400 pm or less, 300 pm or less, or 250 pm or less, or the foam may have an average pore size from about 100 to about 250 pm, about 110 to about 220 pm, about 120 to about 210 pm, or from about 130 and 200 pm.27. The method according to any one or more of the preceding paragraphs, wherein the polymeric particles have a particle size in the range of from about 50 nm to about 20 microns; optionally, the polymeric particles have a particle size in the range of from about 10 nm to about 20 microns, about 10 nm to about 10 microns, about 10 nm to about 5 microns, about 10 nm to about 1 micron, about 50 nm to about 20 microns, about 50 nm to about 10 microns, about 50 nm to about 5 microns, about 50 nm to about 1 micron, about 100 nm to about 20 microns, about 100 nm to about 10 microns, about 100 nm to about 5 microns, or about 100 nm to about 1 micron, or about 10, 20, 50, 100, 200, or 500 nm, or about 1, 2, 5, 10, or 20 microns; optionally, the polymeric particles may have a particle size distribution D90 of from about 1 pm to about 100 pm, or it may be from about 1 pm to about 50 pm, about 1 pm to about 10 pm, about 10 pm to about 50 pm, about 5 pm to about 50 pm, about 10 pm to about 20 pm, about 5 pm to about 10 pm, or about 5 pm to about 25 pm, or about 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, 50, or 100 pm; optionally, the polymeric particles may have a particle size distribution D50 of from about 0.5 pm to about 50 pm, or it may be from about 0.5 pm to about 30 pm, about 0.5 pm to about 10 pm, about 1 pm to about 30 pm, about 5 pm to about 20 pm, about 5 pm to about 10 pm, about 7 pm to about 10.5 pm, or about 5 pm to about 25 pm, or about 0.5, 1, 1.1, 1.2, 1.5, 2, 5, 10, 11, 12, 15, 20, or 50 pm; optionally, the polymeric particles may have a particle size distribution Dio of from about 0.1 pm to about 20 pm, or it may be from about 0.1 pm to about 5 pm, about 0.1 pm to about 10 pm, about 1 pm to about 20 pm, about 1 pm to about 10 pm,about 3 pm to about 6 pm, about 3 pm to about 10 pm, or about 3 pm to about 20 pm, or about 0.1, 0.5, 1, 1.1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, or 20 pm.28. The method according to any one or more of the preceding paragraphs, wherein the aqueous phase, the solvent and / or the emulsifier are recovered for re-use.29. The method according to any one or more of the preceding paragraphs, with the proviso that the feedstock polymer is not chemically modified prior to forming said polymer solution; optionally the chemical structure and composition of the polymeric particle products is substantially the same as the feedstock polymer.30. The method according to any one or more of the preceding paragraphs, wherein the mixture comprises substantially no water insoluble and non-volatile hydrophobic additives having a molecular weight below about 1000 Da.31. The method according to any one or more of the preceding paragraphs, wherein the polymer solution, aqueous phase, and mixture comprises substantially no monomer and / or wherein the method does not include a polymerisation step.32. Polymeric particles produced according to the method according to any one or more of the preceding paragraphs.33. Use of the polymeric particles according to any one or more of the preceding paragraphs to produce a composite material (e.g. construction, or coatings), a foam, a membrane (e.g. for water filtration), a material for battery applications, a material for thermal and / or acoustic insulation or absorption, an implantable material for biomedical engineering, additive for asphalt, or an electromagnetic shielding material (e.g. for the defence and / or aviation industry).34. A method for promoting degradation of a waste polymer, the method comprising the steps of: dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase, removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; and exposing the polymeric particles to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; andwherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms; optionally, the water may be at an elevated temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, when it is combined with the polymer solution.35. A method for promoting degradation of a waste polymer, the method comprising the steps of: dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase, removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; removing the aqueous phase under such conditions to produce a foam comprising the waste polymer; and exposing the foam to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; and wherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms; optionally, the water may be at an elevated temperature of from about 40 °C to about 95 °C, about 50 °C to about 95 °C, about 60 °C to about 95 °C, about 40 °C to about 80 °C, about 40 °C to about 70 °C, about 40 °C to about 60 °C, or about 40 °C to about 50 °C, when it is combined with the polymer solution.36. The method according to any one or more of the preceding paragraphs, wherein the foam is an aerogel.37. The method according to any one or more of the preceding paragraphs, wherein the foam comprises one or more fillers, optionally wherein the one or more fillers include one or more radical producing species.38. The method according to any one or more of the preceding paragraphs, wherein the one or more radical producing species generate radicals upon irradiation with electromagnetic radiation, heat, optionally UV and / or visible light radiation.39. The method according to any one or more of the preceding paragraphs, wherein the one or more radical producing species comprise graphene oxide.40. The method according to any one or more of the preceding paragraphs, wherein the conditions capable of degrading the waste polymer are such that the waste polymer is degraded by one or more processes selected from the group consisting of photodegradation, thermo- oxidative degradation, hydrolytic degradation and biodegradation by microorganisms.41. The method according to one or more of the preceding paragraphs, wherein the method enables the separation of different polymers from a mixture of feedstock polymers, optionally by varying the dissolution conditions (e.g. temperature) of the polymer solution prior to combining the polymer solution and the aqueous phase; optionally the method further comprises a separation step, whereby the dissolution conditions, such as the temperature of the polymer solution, are varied to thereby enable separation of one or more feedstock polymers (e.g. based on their different solubility properties).[000120] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. In particular, features of any one of the various described examples may be provided in any combination in any of the other described examples. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only.

Claims

Claims:

1. A method for producing polymeric particles from a substantially water- insoluble feedstock polymer, the method comprising the steps of: providing a polymer solution comprising the feedstock polymer dissolved in a solvent; providing an aqueous phase comprising at least one emulsifier and being at temperature of from about 40 °C to about 95 °C; and combining the polymer solution and the aqueous phase under such conditions to produce a mixture comprising the polymeric particles dispersed in the aqueous phase; wherein the mixture comprises less than 0.2 wt.% relative to the total weight of the mixture, or less than 2.5 wt.% of the weight of the polymer phase, of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

2. The method of claim 1, wherein the feedstock polymer is a waste polymer; and / or wherein the feedstock polymer is substantially hydrophobic.

3. The method of claim 1 or 2, wherein the feedstock polymer is selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and combinations thereof; or wherein the polymer feedstock is a polyolefin; or wherein the feedstock polymer is selected from the group consisting of low (branched) and high (linear) density polyethylene, polypropylene, poly(propyleneZethylene), other homo- and copolymers of alpha-olefins including poly (4-methylpentene-l), poly (1-butene), polyisobutylene and higher homologs, poly (ethylene / vinyl acetate), poly(ethylene / maleic anhydride), poly(ethylene / isobutylene), chlorinated or chlorosulfonated polyethylene, natural rubber (cis- 1,4- polyisoprene), chlorinated, oxidized or cyclized rubber, rubber hydro-chloride, gutta percha or balata, (trans-polyisoprene), the corresponding synthetic polyisoprenes, poly(styrene / butadiene) rubber (SBR), poly(butadieneZ crylonitrile), cis- or trans- 1 ,4-polybutadiene, poly(isopreneZisobutylene), neoprene, ethylene / propylene / di-ene terpolymers (EPDM), polystyrene, copolymers of styrene with acrylonitrile, fumaronitrile, 2,5-dichlorostyrene, N-vinylcarbazole, N,N-diphenylacrylamide, divinyl benzene or methyl methacrylate, poly(alpha-methylstyrene), poly(p-tert-butylstyrene), polychlorostyrene, poly(acrylonitrile / butadiene / styrene) resin (ABS), coumarone / indenes, polyterpenes, polymers or copolymers from acrylic, methacrylic, hydroxyalkyl acrylic or methacrylic, cyano acrylic or methacrylic acids or their methyl, ethyl or lauryl esters, polyacrylonitrile, vinyl acetate homopolymer or copolymers with dibutyl fumarate, vinyl stearate, vinyl chloride, 2-ethyl-hexyl acrylate or ethyl acrylate, poly(vinyl butyral), homopolymers of vinyl chloride or vinylidene chloride or copolymers with each other or with diethyl fumarate, diethyl maleate, acrylates or methacrylates, polychlorotrifluoroethylene, polyvinyl or vinylidene fluoride and copolymers with chlorotrifluoroethylene or hexafluoropropylene, synthetic superpolyamides or nylons 6, 6 / 6,6 / 10, 11 or 12 or their copolymers, poly (vegetable oil acid / ethylene diamine), polyoxymethylene, poly(ethylene oxide), ethylene dihalide / alkali sulfide polysulfide rubbers, cellulose acetate, acetate butyrate, propionate, acetate propionate or nitrate, ethyl cellulose, poly(ethylene terephthalate) or other polyesters of polyhydric alcohols and dicarboxylic acids, polyether, polyester or polyester / polyamide polyurethanes, phosgene / bisphenol A polycarbonates, poly(2,6-dimethyl phenylene oxide), poly(diphenylene sulfone), poly(p- oxybenzoate), poly(phenylene amide), poly(p-phenylenes), poly(xylylenes), aromatic dianhy-dride / aromatic amine polyimides, polybenzimidazole, polybenzo thiazole, polybenzoxazole, poly thiadiazole, polyoxadiazole, polyphenyltriazole, polyphenylsilsesquioxane, silicon / nitrogen, phosphorus / nitrogen or boron / nitrogen inorganic linear polymers, phenol, urea or melamine formaldehyde condensation polymers, styrenated unsaturated polyesters, epoxy resins, polyamines, polyamides, polysulfides, poly dimethylsiloxane or other polysilicones, alkyd resins, diallyl phthalate or ally diglycol carbonate prepolymers, furane resins, phenolic furfural, polyvinyl formal, polyvinyl acetal, and copolymers and combinations thereof.

4. The method of any one of claims 1 to 3, wherein the solvent is a substantially waterinsoluble and / or hydrophobic organic solvent.

5. The method of any one of claims 1 to 4, wherein the solvent is selected from the group consisting of ethers; esters; aliphatic, alicyclic, and aromatic hydrocarbons; halogenated derivatives thereof; and mixtures thereof; or wherein the solvent is selected from the group consisting of cyclopentanol, methyl ethyl ketone, methyl isobutyl ketone, secondary butyl methyl ketone, diethyl ketone, ethyl isopropyl ketone, diisopropyl ketone, diethyl ether, sec-butyl ether, petroleum ether, ligroin, propyl acetate, butyland isobutyl acetate, amyl and isoamyl acetate, propyl and isopropyl propionate, ethyl butyrate, pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, methylene chloride, carbon tetrachloride, hexyl chloride, chloroform, ethylene di-chloride, benzene, toluene, xylene, chlorobenzene, and mixtures thereof; or wherein the solvent is selected from the group consisting of xylene, toluene, benzene, chlorobenzene, dichloromethane, chloroform, trifluoroacetic acid, and combinations thereof.

6. The method of any one of claims 1 to 5, wherein the emulsifier is selected from the group consisting of non-ionic, anionic or cationic oil-in-water functioning emulsifying agents, optionally wherein the emulsifier comprises sodium dodecyl sulfonate (SDS).

7. The method of any one of claims 1 to 6, wherein the conditions to produce the polymeric particles dispersed in the aqueous phase comprises the step of removing the solvent, preferably by evaporation or distillation.

8. The method of any one of claims 1 to 7, wherein the amount of the feedstock polymer in the polymeric particles is about 95 wt.% or more; and / or wherein the polymeric particles have a Tgthat is within about ± 1, 2, 3, 4, or 5 °C of, preferably substantially identical to, the Tgof the feedstock polymer; and / or wherein the Young's modulus of a bulk material made from the polymeric particles is at least about 80, 85, 90, 95, or 99 % of, preferably substantially identical to, the Young's modulus of a substantially similar bulk material made from the feedstock polymer.

9. The method of any one of claims 1 to 8, wherein the polymeric particles dispersed in the aqueous phase are in the form of an emulsion.

10. The method of any one of claims 1 to 9, wherein the aqueous phase is heated to from about 40 °C to about 95 °C prior to mixing with the polymer solution, such that the polymer solution does not substantially precipitate on contact with the aqueous phase.

11. The method of any one of claims 1 to 10, wherein the polymeric particles dispersed in the aqueous phase are formed by mixing at high shear and / or by using sonication.

12. The method of any one of claims 1 to 11, wherein the concentration of said polymeric particles suspended in said water phase is from about 1 wt.% to about 40 wt.%, preferably from about 2 wt.% to about 10 wt.%, more preferably about 5 wt.%; and / orwherein the weight ratio of the solvent to the feedstock polymer is from about 20:1 to about 1:1, preferably from about 10:1 to about 2:1, more preferably about 5:1.

13. The method of any one of claims 1 to 12, which does not comprise a phase inversion step.

14. The method of any one of claims 1 to 13, wherein the aqueous phase having the polymeric particles dispersed therein is evaporated to thereby provide a substantially dry powder or slurry of said polymeric particles; or wherein the aqueous phase having the polymeric particles dispersed therein is removed under such conditions to form a foam comprising the polymer.

15. The method of any one of claims 1 to 14, wherein the polymeric particles have a particle size in the range of from about 50 nm to about 20 microns.

16. The method of any one of claims 1 to 15, wherein the aqueous phase, the solvent and / or the emulsifier are recovered for re-use.

17. The method of any one of claims 1 to 16, with the proviso that the feedstock polymer is not chemically modified prior to forming said polymer solution.

18. The method of any one of claims 1 to 17, wherein the mixture comprises substantially no water insoluble and non-volatile hydrophobic additives having a molecular weight below about 1000 Da.

19. The method of any one of claims 1 to 18, wherein the polymer solution, aqueous phase, and mixture comprises substantially no monomer and / or wherein the method does not include a polymerisation step.

20. Polymeric particles produced according to the method of any one of claims 1 to 19.

21. Use of the polymeric particles of claim 20 to produce a composite material (e.g. construction, or coatings), a foam, a membrane (e.g. for water filtration), a material for battery applications, a material for thermal and / or acoustic insulation or absorption, an implantable material for biomedical engineering, additive for asphalt, or an electromagnetic shielding material (e.g. for the defence and / or aviation industry).

22. A method for promoting degradation of a waste polymer, the method comprising the steps of:dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase, removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; and exposing the polymeric particles to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; and wherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that are substantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

23. A method for promoting degradation of a waste polymer, the method comprising the steps of: dissolving said waste polymer in an organic solvent to form a polymer solution, combining water, surfactant and said polymer solution under such conditions to produce a mixture comprising the polymer dispersed in an aqueous phase, removing the organic solvent under such conditions to provide polymeric particles dispersed in said aqueous phase; removing the aqueous phase under such conditions to produce a foam comprising the waste polymer; and exposing the foam to conditions capable of degrading the waste polymer; wherein the water is at an elevated temperature of from about 40 to about 95°C when it is combined with the polymer solution; and wherein the mixture comprises less than 0.03 wt.% in total of hydrocarbons, hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters, that aresubstantially water insoluble and non-volatile, and have a terminal aliphatic hydrocarbyl group of at least 8 carbon atoms.

24. The method of claim 23, wherein the foam is an aerogel; and / or wherein the foam comprises one or more fillers, optionally wherein the one or more fillers include one or more radical producing species, wherein the one or more radical producing species generate radicals upon irradiation with electromagnetic radiation, optionally UV and / or visible light radiation; and / or wherein the one or more radical producing species comprise graphene oxide.

25. The method of any one of claims 22 to 24, wherein the conditions capable of degrading the waste polymer are such that the waste polymer is degraded by one or more processes selected from the group consisting of photodegradation, thermo-oxidative degradation, hydrolytic degradation and biodegradation by microorganisms.

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