SAME

FIELD

[0001] The present disclosure relates generally to improved polyester copolymers and methods of making the same. Particularly, embodiments of the present disclosure relate to improved chemically crosslinked polyester copolymers and methods of making the same.

BACKGROUND

[0002] The use of membranes to separate aromatics from saturates has long been pursued by the academic and industrial communities. Many membrane materials have been reported, among which polyimide-based membranes have shown great separation performance and good stability. However, uncrosslinked polyimide membranes can suffer fast degradation due to the high solubility of the polymer in organic vapors. Although advances in copolymer technology have shown improved stability and separation performance, there are still several issues. For example, a lack of control of key variables during synthesis can lead to poor repeatability of the synthesis methods, and the gelling of the polymer after chain extension, thus introducing micro-gel particles in coated films and leading to defects in the membranes. Improvements in polymeric membrane technology could greatly expand the design space of certain industries, such as hydrocarbon refining, water purification, gas separation, energy production, and the like. As such, improved copolymers and methods of making said copolymers for use in membranes are desirable. Embodiments of the present disclosure address this need as well as other needs that will become apparent upon reading the description below in conjunction with the drawings.

BRIEF SUMMARY OF THE INVENTION

[0003] Briefly described, embodiments of the presently disclosed subject matter generally relate to polyester copolymers, and, more particularly, to improved chemically crosslinked polyester copolymers. An exemplary embodiment of the present invention can provide a method of making a polymer, comprising: mixing at least a polyester diol with an anhydride to obtain a first polymeric mixture; dissolving the first polymeric mixture in a first solvent to obtain a first solution; adding, to the first solution, a second solution comprising a diamine and a second solvent to obtain a second polymeric mixture; wherein the second polymeric mixture has viscosity of from 50 cP to 1000 cP at room temperature after stirring.

[0004] In any of the embodiments disclosed herein, the adding can further comprise dehydrating the polyester diol with the anhydride at a temperature of from 140 °C or greater. [0005] In any of the embodiments disclosed herein, the adding can further comprise polymerizing the first solution at a temperature of from -15 °C to 70 °C.

[0006] In any of the embodiments disclosed herein, the method can further comprise mixing in, at a rate of addition during the adding, an additional amount of the first solvent to the second polymeric mixture.

[0007] In any of the embodiments disclosed herein, the rate of addition of the additional amount of the first solvent can be controlled to obtain a desired concentration of the second polymeric mixture.

[0008] In any of the embodiments disclosed herein, the rate of addition can have an addition time from 5 minutes to 30 minutes.

[0009] In any of the embodiments disclosed herein, the dehydrating can occur at a temperature of 170 °C or greater.

[0010] In any of the embodiments disclosed herein, the dehydrating can further comprise slowly ramping the temperature of the first polymeric mixture to the desired temperature for 1 hour or greater.

[0011] In any of the embodiments disclosed herein, the anhydride can comprise pyromellitic dianhydride (PMDA).

[0012] In any of the embodiments disclosed herein, the diamine can comprise 4,4-methylene bis(2-chloroaniline) (MOCA).

[0013] In any of the embodiments disclosed herein, the first solvent, the second solvent, or a combination thereof can comprise dimethylformamide (DMF).

[0014] Another embodiment of the present disclosure can provide a copolymer solution, comprising: a first polymer chain, comprising one or more capped ends formed by reacting a polyester diol with an anhydride; a second polymer chain, comprising two or more repeating units of the first polymer chain propagated from the one or more capped ends; and a third polymer chain, comprising one or more repeating units of the first polymer chain having at least one branched chain propagating from the one or more capped ends; wherein the copolymer solution has a viscosity of from 50 cP to 1000 cP at room temperature; and wherein each of the first polymer chain, the second polymer chain, and the third polymer chain is independently capable of crosslinking with the first polymer chain, the second polymer chain, the third polymer chain, or a combination thereof.

[0015] In any of the embodiments disclosed herein, the anhydride can comprise pyromellitic dianhydride (PMDA). [0016] In any of the embodiments disclosed herein, the one or more capped ends can comprise an anhydride functional group.

[0017] In any of the embodiments disclosed herein, the one or more capped ends can be configured to propagate chains via esterification.

[0018] In any of the embodiments disclosed herein, the one or more capped ends can have the structure

[0019] wherein R comprises the first polymer chain.

[0020] In any of the embodiments disclosed herein, the one or more capped ends can have the structure

[0021] wherein R comprises the first polymer chain and R’ comprises the at least one branched chain.

[0022] Another embodiment of the present disclosure can provide a method of making a copolymer solution, comprising: dehydrating at least a polyester diol with an anhydride to obtain a first copolymer mixture; adding, to the first copolymer mixture in the presence of a first solvent, a functional solution comprising a diamine and a second solvent to obtain a second copolymer mixture; polymerizing the second copolymer mixture to obtain a copolymer solution, comprising: a first polymer chain, comprising one or more capped ends formed by reacting the polyester diol with the anhydride; a second polymer chain, comprising two or more repeating units of the first polymer chain propagated from the one or more capped ends; and a third polymer chain, comprising one or more repeating units of the first polymer chain having at least one branched chain propagating from the one or more capped ends. [0023] In any of the embodiments disclosed herein, the copolymer solution can have a viscosity of from 50 cP to 1000 cP at room temperature.

[0024] In any of the embodiments disclosed herein, each of the first polymer chain, the second polymer chain, and the third polymer chain can be independently capable of crosslinking with the first polymer chain, the second polymer chain, the third polymer chain, or a combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate multiple embodiments of the presently disclosed subject matter and serve to explain the principles of the presently disclosed subject matter. The drawings are not intended to limit the scope of the presently disclosed subject matter in any manner.

[0026] Fig. 1 is a reaction scheme for making a copolymer solution according to some embodiments of the present disclosure;

[0027] Fig. 2 is a flowchart of a method for making a copolymer solution according to some embodiments of the present disclosure;

[0028] Fig. 3 is a flowchart of a method for making a copolymer solution according to some embodiments of the present disclosure;

[0029] Fig. 4 is a reaction scheme for making a copolymer solution according to some embodiments of the present disclosure;

[0030] Fig. 5 a is a Nuclear Magnetic Resonance (NMR) spectroscopy graph of a copolymer solution according to some embodiments of the present disclosure; and

[0031] Fig. 5b is a Nuclear Magnetic Resonance (NMR) spectroscopy graph of several copolymer solutions according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

[0032] Although certain embodiments of the disclosure are explained in detail, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the disclosure is limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. Other embodiments of the disclosure are capable of being practiced or carried out in various ways. Also, in describing the embodiments, specific terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. [0033] Herein, the use of terms such as“having,”“has,”“including,” or“includes” are open- ended and are intended to have the same meaning as terms such as“comprising” or“comprises” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as“can” or“may” are intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.

[0034] The components described hereinafter as making up various elements of the disclosure are intended to be illustrative and not restrictive. Many suitable components that would perform the same or similar functions as the components described herein are intended to be embraced within the scope of the disclosure. Such other components not described herein can include, but are not limited to, for example, similar components that are developed after development of the presently disclosed subject matter.

[0035] As used herein, the term“room temperature” means about 70°F.

[0036] Disclosed herein are copolymer solutions comprising at least a first polymer chain, a second polymer chain, and a third polymer chain. The first polymer chain may comprise a soft, or polymeric, segment. For example, the soft segment of the first polymer chain may have the structure of poly(ethylene glycol adipate) (EGA). Other suitable examples of a soft segment of the first polymer chain can include, but are not limited to, any polyester diols, any aliphatic polyester diols, polycaprolactone, polypentadecalactone, polydodecanlactone, polyundecanlactone, polybutylene adipate, polyethyldodecanoate, polyhexylnonanoate, polybutylene succinate, combinations thereof, and the like. It is understood that the soft segment of the first polymer chain may have the structure of any polyester diol. In some embodiments, the first polymer chain may comprise one or more capped ends. For instance, both ends of the first polymer chain may be terminated with a capped end. As used herein, the term“capped end” or“capped ends” will refer to ends of polymer chains terminating in a functional structure. For example, a soft segment of a first polymer chain, such as EGA, may have capped ends comprising a structure of pyromellitic dianhydride (PMDA). The capped ends disclosed herein may have a structure of any anhydride compound. Suitable examples of an anhydride can include, but are not limited to, formic anhydride, acetic anhydride, propanoic anhydride, butanoic anhydride, maleic anhydride, cyclic anhydride, combinations thereof, and the like. By way of illustration, a soft segment EGA polymer may be reacted with PMDA to form a first polymer chain with one or more capped ends, having a structure such as: wherein R comprises the first polymer chain. It is to be understood that EGA and PMDA are illustrative, and one of ordinary skill in the art would be able to select any polyester diol and any anhydride to form the first polymer chain with capped ends.

[0037] The second polymer chain may comprise multiple repeating units of the first polymer chain. In other words, the second polymer chain is an extended chain polymer of the first polymer chain. In some embodiments, the second polymer chain may be formed by propagating at the one or more capped ends of the first polymer chain. For example, the propagating can occur through esterification of an alcohol functional group with an anhydride functional group.

[0038] The third polymer chain may comprise multiple repeating units of the second polymer chain and having at least one branched chain propagating from one or more capped ends. In other words, the third polymer may be a three-armed polymer chain wherein the third-arm branch off the main polymer chain propagates from a capped end. When in one of the second or the third polymer chains, the capped ends may have the following structure:

wherein R is a first polymer chain and, in some embodiments, R’ is either an alcohol functional group or an additional first polymer chain. For instance, at least one capped end in the second polymer chain will have repeating units of the first polymer chain in the R position and the R’ position will be occupied by an alcohol functional group. Such an embodiment would create a linear extended chain of repeating units of the first polymer chain with capped ends. At least one capped end in the third polymer chain will have repeating units of the first polymer chain in the R position as well as the R’ position. Such an embodiment would create a three-armed branch of repeating units of the first polymer. [0039] As shown below, the presently disclosed copolymer solution may generally have a first polymer chain, a second polymer chain, and a third polymer chain with such structures as:

respectively, wherein X are the capped ends, X’ is the capped end propagating the extended chain in the second polymer chain, and X” is the capped end propagating the three-armed branch in the third polymer chain. The structure within the parentheses may be the soft segment of the polymer chain and may have any structure of a polyester diol as desired by one of ordinary skill in the art. Additionally, the polyester diol can be present in any amount desired by one or ordinary skill in the art.

[0040] For example, in some embodiments, the polyester diol can be present in the copolymer solution in an amount of 50% or greater (e.g., 51% or greater, 52% or greater, 53% or greater, 54% or greater, 55% or greater, 56% or greater, 57% or greater, 58% or greater, 59% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater, 80% or greater, 81% or greater, 82% or greater, 83% or greater, 84% or greater, 85% or greater, 86% or greater, 87% or greater, 88% or greater, 89% or greater, or 90% or greater) by weight, based on total weight of the copolymer solution. In some embodiments, the polyester diol can be present in the copolymer solution in an amount of 90% or less (e.g., 50% or less, 51% or less, 52% or less, 53% or less, 54% or less, 55% or less, 56% or less, 57% or less, 58% or less, 59% or less, 60% or less, 65% or less, 70% or less, 75% or less, 80% or less, 81% or less, 82% or less, 83% or less, 84% or less, 85% or less, 86% or less, 87% or less, 88% or less, or 89% or less) by weight, based on total weight of the copolymer solution. In some embodiments, the polyester diol can be present in the copolymer solution in an amount from 50% to 90% (e.g., from 51% to 89%, from 52% to 88%, from 53% to 87%, from 54% to 86%, from 55% to 85%, from 56% to 84%, from 57% to 83%, from 58% to 82%, from 59% to 81%, or from 60% to 80%) by weight, based on total weight of the copolymer solution.

[0041] By way of illustration and not limitation, the presently disclosed copolymer solution may generally have a first polymer chain, a second polymer chain, and a third polymer chain with such structures as shown in Fig. 1. Fig. 1 illustrates a reaction scheme for making a copolymer solution according to some embodiments of the present disclosure. As shown, EGA and PMDA are chosen as the polyester diol and the anhydride, respectively, and reacted to form a copolymer solution comprising a first polymer chain, a second polymer chain, and a third polymer chain.

[0042] In some embodiments, the copolymer solution may be capable of crosslinking. Each of the first polymer chain, the second polymer chain, and the third polymer chain may be independently capable of crosslinking with the first polymer chain, the second polymer chain, the third polymer chain, or a combination thereof. In other words, a first polymer chain in the copolymer solution can be capable of crosslinking with a second polymer chain, a third polymer chain, another first polymer chain, or multiple other chains. For instance, two or more chains may crosslink to each other via hydrogen bonding at a carboxylic acid group contained on the chains.

[0043] In some embodiments, at least one of the first polymer chain, the second polymer chain, or the third polymer chain may comprise one or more carboxylic acid functional groups. It is understood that other functional groups may be present in the chains. Additionally, it is understood that one or ordinary skill in the art may select the polymer chains to have any functional group to provide a crosslinking means and achieve a desired level or form of crosslinking, such as covalent bonding, ionic bonding, chemical bonding, hydrogen bonding, combinations thereof, and the like. Suitable examples of functional groups capable of providing a crosslinking means can include, but are not limited to, carboxylic acids, ketones, aldehydes, esters, amides, primary amines, secondary amines, azides, pyridines, azoles, diazoles, triazoles, imidazoles, pyrazoles, tetrazoles, oxazoles, furazans, furans, thiazoles, sulfones, sulfanes, acyl fluorides, trifluoromethyls, fluoroethyls, fluoroalkanes, fluoroacetates, and the like.

[0044] In some embodiments, the chains of the copolymer solution can comprise one or more organic functional groups (e.g., two or more, three or more, four or more, five or more, six or more, or seven or more). Suitable examples of an organic functional group can include, but are not limited to: alkanes, alkenes, alkynes, aromatics, benzene or phenyl derivatives, haloalkanes, fluoroalkanes, chloroalkanes, bromoalkanes, iodoalkanes, alcohols, ketones, aldehydes, acyl halides, carbonates, carboxylates, carboxylic acids, esters, hydroperoxides, peroxides, ethers, hemiacetals, hemiketals, acetals, orthoesters, heterocycles, organic acid anhydrides, amides, amines, imines, imides, azides, azo compounds, cyanates, nitrates, nitriles, nitrites, nitro compounds, nitroso compounds, oximes, pyridine or pyridine derivatives, carbamate esters, thiols, sulfides, disulfides, sulfoxides, sulfones, sulfinic acids, sulfonic acids, sulfonate esters, thiocyanates, thioketones, thials, thiocarboxylic acids, thioesters, phosphines, phosphanes, phosphonic acids, phosphates, phosphodiesters, boronic acids, boronic esters, borinic acids, borinic esters, epoxides, cycloalkanes, pyrroles, thiophenes, pyrans, furans, dioxins, furfurals, imidazoles, pyrimidines, toluenes, thiazoles, pyrazoles, oxazoles, triazoles, purines, or any combination thereof. Additional functional groups known to one of ordinary skill in the art may be chosen to confer certain desirable properties to the individual polymer chains or the copolymer solution as a whole. In some embodiments, the organic compound can comprise multiple instances of the same functional group.

[0045] One of ordinary skill in the art would appreciate that a Brookfield viscometer can be used to measure the viscosity of a solution. The following viscosities of the copolymer solutions disclosed herein were measured using a Brookfield viscometer at 50 rpm. Embodiments of the present disclosure can provide a copolymer solution having a viscosity of 50 cP or greater (e.g., 55 cP or greater, 60 cP or greater, 65 cP or greater, 70 cP or greater, 75 cP or greater, 80 cP or greater, 85 cP or greater, 90 cP or greater, 95 cP or greater, 100 cP or greater, 105 cP or greater, 110 cP or greater, 115 cP or greater, 120 cP or greater, 125 cP or greater, 130 cP or greater, 135 cP or greater, 140 cP or greater, 145 cP or greater, 150 cP or greater, 155 cP or greater, 160 cP or greater, 165 cP or greater, 170 cP or greater, 175 cP or greater, 180 cP or greater, 185 cP or greater, 190 cP or greater, 195 cP or greater, 200 cP or greater, 205 cP or greater, 210 cP or greater, 215 cP or greater, 220 cP or greater, 225 cP or greater, 230 cP or greater, 235 cP or greater, 240 cP or greater, 245 cP or greater, 250 cP or greater, 300 cP or greater 350 cP or greater, 400 cP or greater, 450 cP or greater, 500 cP or greater, 550 cP or greater 600 cP or greater, 650 cP or greater, 700 cP or greater, 750 cP or greater, 800 cP or greater, 850 cP or greater, 900 cP or greater, 950 cP or greater, or 1000 cP or greater) at room temperature.

[0046] In some embodiments, the copolymer solution can have a viscosity of 1000 cP or less (e.g., 50 cP or less, 55 cP or less, 60 cP or less, 65 cP or less, 70 cP or less, 75 cP or less, 80 cP or less, 85 cP or less, 90 cP or less, 95 cP or less, 100 cP or less, 105 cP or less, 110 cP or less, 115 cP or less, 120 cP or less, 125 cP or less, 130 cP or less, 135 cP or less, 140 cP or less, 145 cP or less, 150 cP or less, 155 cP or less, 160 cP or less, 165 cP or less, 170 cP or less, 175 cP or less, 180 cP or less, 185 cP or less, 190 cP or less, 195 cP or less, 200 cP or less, 205 cP or less, 210 cP or less, 215 cP or less, 220 cP or less, 225 cP or less, 230 cP or less, 235 cP or less, 240 cP or less, 245 cP or less, 250 cP or less, 300 cP or less 350 cP or less, 400 cP or less, 450 cP or less, 500 cP or less, 550 cP or less 600 cP or less, 650 cP or less, 700 cP or less, 750 cP or less, 800 cP or less, 850 cP or less, 900 cP or less, or 950 cP or less) at room temperature. [0047] In some embodiments, the copolymer solution can have a viscosity from 50 cP to 1000 cP (e.g., from 50 cP to 900 cP, from 50 cP to 800 cP, from 50 cP to 700 cP, from 50 cP to 600 cP, from 50 cP to 500 cP, from 50 cP to 400 cP, from 50 cP to 300 cP, from 50 cP to 200 cP, from 55 cP to 215 cP, from 60 cP to 210 cP, from 65 cP to 205 cP, from 70 cP to 200 cP, from 75 cP to 200 cP, from 80 cP to 200 cP, from 85 cP to 200 cP, from 90 cP to 200 cP from 95 cP to 200 cP, from 100 cP to 200 cP, from 105 cP to 200 cP, from 110 cP to 200 cP, from 110 cP to 190 cP, from 115 cP to 185 cP, from 120 cP to 180 cP, from 125 cP to 175 cP, from 130 cP to 170 cP, from 135 cP to 165 cP, or from 140 cP to 160 cP) at room temperature.

[0048] Embodiments of the present disclosure can provide methods of making a copolymer solution. The method may comprise providing a polyester diol, an anhydride, and a diamine. Embodiments of the present disclosure can provide a method of making a copolymer solution, comprising mixing at least a polyester diol with an anhydride to obtain a first polymeric solution. It is understood that other components may be present, such as inhibitors, catalysts, defoamers, solvents, nonsolvents, surfactants, and the like. The first polymer solution is then dissolved in a first solvent to obtain a first solution, and a diamine dissolved in a second solvent

(via a second solution) is added to the first solution to obtain a second polymeric mixture. The diamine may be any suitable diamine chosen by one of ordinary skill in the art, such as 4,4- methylene bis(2-chloroaniline) (MOCA). It is understood that other components may be present in the second solution.

[0049] Embodiments of the present disclosure can provide a diamine for use in methods of making a copolymer solution. For example, a polyester diol and an anhydride can be reacted with 4,4-methylene bis(2-chloroaniline) (MOCA) to form a copolymer solution. Other suitable examples of a diamine can include, but are not limited to, diaminomethane, methylene dianiline, ethylenediamine, 1,3-diaminopropane, putrescine, cadaverine, xylenediamine, phenyldiamine, and the like. The diamine may react with the polyester diol and the anhydride at the capped ends of the copolymer solution. For example, when the anhydride comprises PMDA to form the capped ends, the reaction with MOCA as the diamine may give the capped ends the following structure: wherein R is a first polymer chain and, in some embodiments, R’ is either an alcohol functional group or an additional first polymer chain. For instance, at least one capped end in the second polymer chain will have repeating units of the first polymer chain in the R position and the R’ position will be occupied by an alcohol functional group. Such an embodiment would create a linear extended chain of repeating units of the first polymer chain with capped ends. At least one capped end in the third polymer chain will have repeating units of the first polymer chain in the R position as well as the R’ position. Such an embodiment would create a three-armed branch of repeating units of the first polymer.

[0050] As shown below, the presently disclosed copolymer solution may generally have a first polymer chain, a second polymer chain, and a third polymer chain with such structures as:

respectively, wherein X are the capped ends, X’ is the capped end propagating the extended chain in the second polymer chain, X” is the capped end propagating the three-armed branch in the third polymer chain, and A is the diamine functional group bound to the capped ends and propagating the chain extension. The structure within the parentheses may be the soft segment of the polymer chain and may have any structure of a polyester diol as desired by one of ordinary skill in the art. Additionally, the polyester diol can be present in any amount.

[0051] The parentheticals m and n above may be any integer representing repeating monomer units of the first, second, or third polymer chains as disclosed above. In some embodiments, m can be an integer representing the polyester diol. As such, m can be the size of a polyester diol desired by one of ordinary skill in the art to confer a desirable property to the copolymer solution, such as from 1 to 12. In some embodiments, n is an integer representing the size of the polymer chains in the copolymer solution, such as from 5 to 100,000. In another embodiment, n is from 10 to 50,000, or from 100 to 20,000, or from 1,000 to 20,000.

[0052] A variety of physical mixing methods are suitable for use in the present invention, including conventional mortar and pestle mixing, magnetic stir bars, rollers, stir rods, and high shear mixing, such as with a high-speed mixer, homogenizers, microfluidizers, high impact mixing, Morehouse mills, Buxton knife mills, Gaulin homogenizers, colloid mills, rotating knife-edge mills, rotor-stator mills, and three-roll mills, and ultrasonication methods.

[0053] Embodiments of the present disclosure can provide a solvent for at least the first solvent and the second solvent as described above. The solvent can be any substance able to substantially dissolve the desired components to create a liquid solution at room temperature and pressure. Suitable examples of a solvent can include, but are not limited to, nonpolar solvents, polar aprotic solvents, polar protic solvents, water-miscible solvents, non coordinating solvents, or a combination thereof. There are many examples of appropriate solvents known to one of ordinary skill in the art, but suitable examples can include, but are not limited to, acetaldehyde, acetic acid, acetone, acetonitrile, butanediol, butoxyethanol, butyric acid, diethanolamine, diethylenetriamine, dimethyl acetamide (DMAc), dimethylformamide (DMF), dimethoxy ethane, dimethyl sulfoxide (DMSO), dioxane, ethanol, ethylamine, ethylene glycol, formic acid, furfuryl alcohol, glycerol, methanol, methyl diethanolamine, methyl isocyanide, N-methyl-2-pyrrolidone (NMP), propanol, propanediol, propanoic acid, propylene glycol, pyridine, tetrahydrofuran (THF), triethylene glycol, dimethyl hydrazine, hydrazine, hydrofluoric acid, hydrogen peroxide, nitric acid, sulfuric acid, pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, chloroform, diethyl ether, dichloromethane, or a combination thereof. Additionally, the solvent can be selected by one of ordinary skill in the art to improve the wetting and adhesion of the solution on the porous support material based on the surface tension of the solution. [0054] In some embodiments, the polymer can be present in the solvent in an amount of 0.5% or greater (e.g., 0.6% or greater, 0.7% or greater, 0.8% or greater, 0.9% or greater, 1% or greater, 1.1% or greater, 1.2% or greater, 1.3% or greater, 1.4% or greater, 1.5% or greater, 1.6% or greater, 1.7% or greater, 1.8% or greater, 1.9% or greater, 2% or greater, 2.1% or greater, 2.2% or greater, 2.3% or greater, 2.4% or greater, 2.5% or greater, 2.6% or greater, 2.7% or greater, 2.8% or greater, 2.9% or greater, 3% or greater, 3.1% or greater, 3.1% or greater, 3.3% or greater, 3.4% or greater, 3.5% or greater, 3.6% or greater, 3.7% or greater, 3.8% or greater, 3.9% or greater, 4% or greater, 4.1% or greater, 4.2% or greater, 4.3% or greater, 4.4% or greater, 4.5% or greater, 4.6% or greater, 4.7% or greater, 4.8% or greater, 4.9% or greater, 5% or greater, 5.1% or greater, 5.2% or greater, 5.3% or greater, 5.4% or greater, 5.5% or greater, 5.6% or greater, 5.7% or greater, 5.8% or greater, 5.9% or greater, or 6% or greater) based on total weight of the solution.

[0055] In some embodiments, the polymer can be present in the solvent in an amount of 6% or less (e.g., 0.5% or less, 0.6% or less, 0.7% or less, 0.8% or less, 0.9% or less, 1% or less, 1.1% or less, 1.2% or less, 1.3% or less, 1.4% or less, 1.5% or less, 1.6% or less, 1.7% or less, 1.8% or less, 1.9% or less, 2% or less, 2.1% or less, 2.2% or less, 2.3% or less, 2.4% or less, 2.5% or less, 2.6% or less, 2.7% or less, 2.8% or less, 2.9% or less, 3% or less, 3.1% or less, 3.1% or less, 3.3% or less, 3.4% or less, 3.5% or less, 3.6% or less, 3.7% or less, 3.8% or less, 3.9% or less, 4% or less, 4.1% or less, 4.2% or less, 4.3% or less, 4.4% or less, 4.5% or less, 4.6% or less, 4.7% or less, 4.8% or less, 4.9% or less, 5% or less, 5.1% or less, 5.2% or less, 5.3% or less, 5.4% or less, 5.5% or less, 5.6% or less, 5.7% or less, 5.8% or less, or 5.9% or less) based on total weight of the solution.

[0056] In some embodiments, the polymer can be present in the solvent in an amount of from 0.5% to 6% (e.g., from 0.5% to 5.9%, from 0.5% to 5.8%, from 0.5% to 5.7%, from 0.5% to 5.6%, from 0.5% to 5.5%, from 0.5% to 5.4%, from 0.5% to 5.3%, from 0.5% to 5.2%, from 0.5% to 5.1%, from 0.5% to 5%, from 0.5% to 4.9%, from 0.5% to 4.8%, from 0.5% to 4.7%, from 0.5% to 4.6%, from 0.5% to 4.5%, from 0.6% to 4.4%, from 0.7% to 4.3%, from 0.8% to 4.2%, from 0.9% to 4.1%, from 1% to 4%, from 1.1% to 3.9%, from 1.2% to 3.8%, from 1.3% to 3.7%, from 1.4% to 3.6%, from 1.5% to 3.5%, from 1.6% to 3.4%, from 1.7% to 3.3%, from 1.8% to 3.2%, from 1.9% to 3.1%, or from 2% to 3%) based on total weight of the solution. In some embodiments, the polymer can be present in the solvent in an amount from about 1% to about 4% based on total weight of the solution. [0057] In some embodiments, when forming the first polymeric mixture, the mixing can further comprise dehydrating the polyester diol and the anhydride. The dehydrating can occur for 1 hour or greater (e.g., 1.5 hours or greater, 2 hours or greater, 2.5 hours or greater, 3 hours or greater, 3.5 hours or greater, 4 hours or greater, 4.5 hours or greater, 5 hours or greater, 5.5 hours or greater, 6 hours or greater, 6.5 hours or greater, 7 hours or greater, 7.5 hours or greater, 8 hours or greater, 8.5 hours or greater, 9 hours or greater, 9.5 hours or greater, 10 hours or greater, 10.5 hours or greater, 11 hours or greater, 11.5 hours or greater, or 12 hours or greater). In some embodiments, the dehydrating can occur for 12 hours or less (e.g., 1 hour or less, 1.5 hours or less, 2 hours or less, 2.5 hours or less, 3 hours or less, 3.5 hours or less, 4 hours or less, 4.5 hours or less, 5 hours or less, 5.5 hours or less, 6 hours or less, 6.5 hours or less, 7 hours or less, 7.5 hours or less, 8 hours or less, 8.5 hours or less, 9 hours or less, 9.5 hours or less, 10 hours or less, 10.5 hours or less, 11 hours or less, or 11.5 hours or less). In some embodiments, the dehydrating can occur from 1 hour to 12 hours (e.g., from 1.5 hours to 11.5 hours, from 2 hours to 11 hours, from 2.5 hours to 10.5 hours, from 3 hours to 10 hours, from 3.5 hours to 9.5 hours, from 4 hours to 9 hours, from 5 hours to 8 hours, from 7.5 to 12 hours, from 1 hour to 7.5 hours, or from 7.5 to 10 hours). In some embodiments, the dehydrating further comprises slowly ramping the temperature of the first polymeric mixture to a desired temperature for 1 hour or greater (e.g., from 1 hour to 7.5 hours, 1 hour).

[0058] In some embodiments, the desired temperature of the dehydrating can be 140 °C or greater (e.g., 145 °C or greater, 150 °C or greater, 155 °C or greater, 160 °C or greater, 165 °C or greater, 170 °C or greater, 175 °C or greater, 180 °C or greater, 185 °C or greater, 190 °C or greater, or 200 °C or greater). In some embodiments, the desired temperature of the dehydrating can be 200 °C or less (e.g., 140 °C or less, 145 °C or less, 150 °C or less, 155 °C or less, 160 °C or less, 165 °C or less, 170 °C or less, 175 °C or less, 180 °C or less, 185 °C or less, or 190 °C or less). In some embodiments, the desired temperature of the dehydrating can be from 140 °C to 200 °C (e.g., from 145 °C to 195 °C, from 150 °C to 190 °C, from 155 °C to 185 °C, from 160 °C to 180 °C, from 160 °C to 175 °C, from 160 °C to 170 °C, or from 160 °C to 165 °C).

[0059] In some embodiments, after adding the second solution to the first solution, the components in the second polymeric mixture may undergo a polymerization reaction. During polymerization, an additional amount of the first solvent may be added to the second polymeric mixture at a rate of addition. The rate of addition may be controlled to obtain a desired concentration of the second polymeric mixture. For instance, the additional amount may be added over a time period of 5 minutes or greater (e.g., 6 minutes or greater, 7 minutes or greater, 8 minutes or greater, 9 minutes or greater, 10 minutes or greater, 15 minutes or greater, 20 minutes or greater, 25 minutes or greater, 26 minutes or greater, 27 minutes or greater, 28 minutes or greater, 29 minutes or greater, or 30 minutes or greater). In some embodiments, the additional amount may be added over a time period of 30 minutes or less (e.g., 5 minutes or less, 6 minutes or less, 7 minutes or less, 8 minutes or less, 9 minutes or less, 10 minutes or less, 15 minutes or less, 20 minutes or less, 25 minutes or less, 26 minutes or less, 27 minutes or less, 28 minutes or less, or 29 minutes or less). In some embodiments, the additional amount may be added over a time period from 5 minutes to 30 minutes (e.g., from 6 minutes to 29 minutes, from 7 minutes to 28 minutes, from 8 minutes to 27 minutes, from 9 minutes to 26 minutes, from 10 minutes to 25 minutes, or from 15 minutes to 20 minutes).

[0060] In some embodiments, the polymerization can occur at a temperature of -15 °C or greater (e.g., -10 °C or greater, -5 °C or greater, 0 °C or greater, 5 °C or greater, 10 °C or greater, 15 °C or greater, 20 °C or greater, 25 °C or greater, 30 °C or greater, 35 °C or greater, 40 °C or greater, 45 °C or greater, 50 °C or greater, 55 °C or greater, 60 °C or greater, 65 °C or greater, or 70 °C or greater). In some embodiments, the polymerization can occur at a temperature of 70 °C or less (e.g., -15 °C or less, -10 °C or less, -5 °C or less, 0 °C or less, 5 °C or less, 10 °C or less, 15 °C or less, 20 °C or less, 25 °C or less, 30 °C or less, 35 °C or less, 40 °C or less, 45 °C or less, 50 °C or less, 55 °C or less, 60 °C or less, or 65 °C or less). In some embodiments, the polymerization can occur at a temperature from -15 °C to 70 °C (e.g., from -10 °C to 65 °C, from -5 °C to 60 °C, from 0 °C to 55 °C, from 5 °C to 50 °C, from 10 °C to 45 °C, from 20 °C to 35 °C, or from 20 °C to 25 °C).

[0061] The copolymer solutions disclosed herein can be used in a variety of applications. For instance, the copolymer solutions can be used for several applications in liquid or gaseous membrane separations, such as hydrocarbon processing or water purification. A person of ordinary skill in the art would recognize from the present disclosure that the resulting copolymer solutions can be manufactured to have any desired form, including, for instance, thin films or hollow fibers.

[0062] Reference will now be made in detail to exemplary embodiments of the disclosed technology, examples of which are illustrated in the accompanying drawings and disclosed herein. Fig. 2 and Fig. 3 depict methods of making a copolymer solution according to some embodiments of the present disclosure.

[0063] Referring first to Fig. 2, in block 210, a polyester diol and an anhydride can be mixed to obtain a first polymeric mixture, as described above. In block 220, the first polymeric mixture can be dissolved in a first solvent to obtain a first solution, as described above. In block 230, a second solution comprising a diamine and a second solvent can be added to the first solution to obtain a second polymeric mixture, as described above. A reaction scheme for block 230 according to some embodiments of the present disclosure can be found in Fig. 4.

[0064] Referring now to Fig. 3, in block 310, at least a polyester diol can be dehydrated with an anhydride to obtain a first copolymer mixture, as described above. In block 320, a functional solution comprising a diamine and a second solvent can be added to the first copolymer mixture in the presence of a first solvent to obtain a second copolymer mixture. A reaction scheme for block 320 according to some embodiments can be found in Fig. 4. In block 330, the second copolymer mixture can be polymerized to obtain a copolymer solution, as described above.

EXAMPLES

[0065] The following examples are provided by way of illustration but not by way of limitation.

Example 1

Materials and Methods

[0066] A 4-liter 3 neck reaction flask was heated by oil bath or heating mantle. 477.6 g of dried poly(ethylene glycol adipate) (EGA) and 104.7 grams of dried pyromellitic dianhydride (PMDA) were added to the reactor. The flask was then evacuated and backflushed with nitrogen gas three times. The in-reactor temperature was slowly ramped to 163 °C over 1 hour, and the reactor was agitated until all reagents melted. The mixture was stirred at 200 rpm and the temperature held for 7.5 hours. The mixture was then cooled to 60 °C and 2000 g of dry dimethyl formamide (DMF) was added to dissolve the material in the 4-liter flask. A sample of the mixture was analyzed using nuclear magnetic resonance spectroscopy (NMR) and compared to a sample of the same method but with no solvent. The comparison can be seen in Fig. 5a. A comparison of the NMR spectra for the above reaction at different reaction times and temperatures can be seen in Fig. 5b.

[0067] The mixture is then transferred to a nitrogen-blanketed 20-liter reactor with a target oxygen level of less than 2 ppm. The old 4-liter flask was rinsed with 900 g DMF to obtain any residual mixture and transferred to the new 20-liter reactor. Another 2667.6 g DMF was then transferred into the 20-liter flask and the solution was stirred at 150 rpm and heated to 35 °C. 64.1 g of 4,4-methylene bis(2-chloroaniline) (MOCA) was dissolved in 250 g DMF in a separate jar and added all at once to the 20-liter reactor. The solution was stirred at the same temperature until an increase in viscosity and torque was observed. Extra DMF was then added to the solution at a rate of lL/mL to reduce the solution to the desired final concentration. The solution was allowed to cool to room temperature while stirring continued. Product was then sealed to prevent exposure to air and stored.

[0068] While the present disclosure has been described in connection with a plurality of exemplary aspects, as illustrated in the various figures and discussed above, it is understood that other similar aspects can be used, or modifications and additions can be made to the described aspects for performing the same function of the present disclosure without deviating therefrom. For example, in various aspects of the disclosure, methods and compositions were described according to aspects of the presently disclosed subject matter. However, other equivalent methods or composition to these described aspects are also contemplated by the teachings herein. Therefore, the present disclosure should not be limited to any single aspect, but rather construed in breadth and scope in accordance with the appended claims.