Copolymers having polyamide blocks and flexible blocks

Abstract

This invention relates to a thermoplastic copolymer comprising semi-crystalline polyamide blocks and flexible blocks, wherein: - the semi-crystalline polyamide blocks contain, by weight, 30% to 75%, preferably 30% to 70% by weight, aliphatic dicarboxylic acids and / or diamines comprising at least 36 carbon atoms, relative to the total weight of the polyamide blocks; the repeating units of the polyamide blocks in the copolymer have an average carbon content greater than or equal to 7; - the flexible blocks comprise blocks derived from polyethylene glycol; and - the weight proportion of the polyamide blocks is 15% to 60% by weight relative to the total weight of the copolymer; and - the weight proportion of the flexible blocks is 40% to 85% by weight relative to the total weight of the copolymer; the melting point of the copolymer of the present invention is equal to or higher than 80°C, preferably higher than 80°C. This invention also relates to a membrane comprising a copolymer for gas separation and a method for preparing the same.

Description

Technical Field

[0001] The present invention relates to a copolymer comprising semi-crystalline polyamide blocks and flexible blocks, a method for preparing such copolymer, and a membrane for gas separation formed from such copolymer. Background Technology

[0002] Greenhouse gas emissions and their impact on global warming have become a major concern. Various technologies have been developed to recover greenhouse gases such as carbon dioxide (CO2) and methane (CH4). Among these, gas separation membranes are under development. Gas separation membranes can also be used in many other applications, such as natural gas purification or novel enthalpy heat exchangers.

[0003] Currently, polymeric materials dominate the market for gas separation applications. For example, copolymers containing polyamide and polyether blocks (also known as PEBA) exhibit good selectivity for CO2 compared to other light gases.

[0004] WO 2018 / 222255 describes a gas separation method using a membrane comprising a crosslinked mixture of a polyether amide copolymer and acrylate-terminated polyethylene glycol.

[0005] US 2022 / 0315701 describes a copolymer containing rigid polyamide blocks and flexible blocks, wherein the copolymer comprises 55% to 90% by weight of flexible blocks and 10% to 45% by weight of polyamide blocks relative to the total weight of the copolymer.

[0006] However, these copolymers tend to have poor solubility in solvents, which limits their application or processing, such as in solvent casting for the manufacture of membranes or thin films.

[0007] Furthermore, these copolymers have relatively low melting points, which further complicates their application or processing in membrane or thin film manufacturing. In fact, copolymers with low melting points may cause pore collapse during the drying process of the membrane.

[0008] Therefore, there is a need for a copolymer that facilitates and simplifies the preparation of gas separation membranes while maintaining good gas permeability and selectivity in the resulting membranes. Summary of the Invention

[0009] First, this invention relates to a thermoplastic copolymer containing semi-crystalline polyamide blocks and flexible blocks, wherein:

[0010] - Relative to the total weight of the polyamide blocks, the semi-crystalline polyamide blocks contain 30% to 75% by weight, preferably 30% to 70% by weight, of aliphatic dicarboxylic acids and / or diamines comprising at least 36 carbon atoms; the repeating units of the polyamide blocks in the copolymer have an average carbon content greater than or equal to 7; the flexible blocks include blocks derived from polyethylene glycol; and

[0011] - The polyamide blocks comprise 15% to 60% by weight relative to the total weight of the copolymer, and the flexible blocks comprise 40% to 85% by weight relative to the total weight of the copolymer.

[0012] - The melting point of the copolymer of the present invention is equal to or higher than 80°C, preferably higher than 80°C.

[0013] According to some embodiments, the polyamide block includes unit X.36 or unit 36.Y, wherein:

[0014] - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms.

[0015] - 36 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 36 carbon atoms, and

[0016] - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms.

[0017] According to some embodiments, the polyamide block includes unit X.44 or unit 44.Y, wherein:

[0018] - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms.

[0019] - 44 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 44 carbon atoms, and

[0020] - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms.

[0021] According to some embodiments, aliphatic dicarboxylic acids and / or diamines comprising at least 36 carbon atoms, preferably 36 carbon atoms or 44 carbon atoms, more preferably 36 carbon atoms, are chain restrictors of semi-crystalline polyamide blocks.

[0022] According to some embodiments, the polyamide block comprises the following units: PA 11, PA 12, PA 536, PA 1036, PA 636, PA 1136, PA 1236, PA 366, PA 11 / 1036, PA 1012 / 1036, PA 1010 / 1036, PA 610 / 636, PA 612 / 636, PA 613 / 636, PA 69 / 636, PA 544, PA 1044, PA 644, PA 1144, PA 1244, PA 446, PA11 / 1044, PA 1012 / 1044, PA 1010 / 1044, PA 610 / 644, PA 612 / 644, PA 613 / 644, PA 69 / 644.

[0023] According to some embodiments, the polyamide block accounts for 20% to 50% by weight, more preferably 30% to 50% by weight, relative to the total weight of the copolymer, and the flexible block accounts for 50% to 80% by weight, more preferably 50% to 70% by weight, relative to the total weight of the copolymer.

[0024] According to some embodiments, the number average molecular weight of the polyamide blocks is from 400 g / mol to 20,000 g / mol, preferably from 500 g / mol to 10,000 g / mol, more preferably from 600 g / mol to 2,500 g / mol, and the number average molecular weight of the flexible blocks is from 200 g / mol to 6,000 g / mol, preferably from 500 g / mol to 3,000 g / mol, more preferably from 600 g / mol to 2,000 g / mol.

[0025] Secondly, the present invention relates to a composition comprising:

[0026] - At least one copolymer as defined above, and

[0027] - At least one additive selected from colorants, UV stabilizers, anti-aging agents, antioxidants, fluidizing agents, anti-abrasion agents, release agents, stabilizers, plasticizers, impact modifiers, surfactants, brighteners, fillers, fibers, waxes, and mixtures thereof.

[0028] The present invention further relates to the use of a copolymer or composition as defined above as a membrane for gas separation.

[0029] The present invention relates to a membrane for gas separation, the membrane comprising a copolymer or a composition as defined above.

[0030] According to some embodiments, the membrane has a thickness of 0.05 µm to 500 µm, preferably 0.10 µm to 250 µm, more preferably less than 20 µm, and even more preferably less than 10 µm.

[0031] The present invention further relates to a method for preparing a membrane, the method comprising the following steps:

[0032] - Supply the copolymers or compositions defined above.

[0033] - Dissolve the copolymer or composition in a solvent to form a solution.

[0034] - Deposit the solution onto the substrate, and

[0035] - Evaporate the solvent.

[0036] The present invention further relates to a method for preparing a membrane as defined above, the method comprising the following steps:

[0037] - Supply a polymer solution comprising a copolymer or composition as defined above dissolved in a solvent.

[0038] - Supply bore fluid.

[0039] - The polymer solution and core liquid are co-extruded downwards into the coagulation bath, and

[0040] - Recover the membrane that has solidified in the coagulation bath.

[0041] - The recovered membrane is dried by solvent exchange or freeze drying.

[0042] The present invention satisfies the above-mentioned needs. More specifically, the present invention provides a copolymer that is easy to process and prepare a gas separation membrane, the membrane having high gas selectivity and permeability. The membrane also exhibits, in particular, high selectivity for carbon dioxide relative to other light gases.

[0043] This is achieved through a copolymer comprising polyamide blocks and flexible blocks, wherein the polyamide blocks comprise a specific proportion of dimer fatty acids or dimer fatty diamines comprising at least 36 carbon atoms.

[0044] The inventors have unexpectedly discovered that the presence of such dimer fatty acids or dimer aliphatic diamines, which are chain restrictors or components of monomer units, can disrupt the crystal structure of the copolymer. Therefore, the solubility of the copolymer in solvents used in its membrane manufacturing process is improved, while the copolymer remains insoluble in reagents (such as washing solutions).

[0045] Furthermore, a melting point of copolymers equal to or higher than 80°C can prevent or at least minimize pore collapse during drying in membrane manufacturing, thereby further promoting their processability as membranes.

[0046] According to certain specific embodiments, the present invention also has one or more of the following advantageous features: improved CO2 selectivity relative to N2 or H2. Detailed Implementation

[0047] The invention will now be described in more detail in a non-limiting manner in the following description.

[0048] This invention relates to a copolymer containing polyamide blocks and flexible blocks. These copolymers are thermoplastic elastomer (TPE) polymers comprising rigid (or hard, having relatively thermoplastic behavior) blocks and flexible (or soft, having relatively elastomeric behavior) blocks.

[0049] The term "polymer" refers to a polymer composed of more than one type of monomer, including polymers derived from two monomers and polymers derived from three or more monomers (also known as ternary polymers).

[0050] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques - Matériaux polyamides (PA) pour moulage et extrusion - Partie 1: Designation”, particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0051] Typically, polyamides contain at least two identical or different repeating units, which are derived from residues of aminocarboxylic acids (also known as amino acids), lactams or dicarboxylic acids (also known as carboxylic acids or diacids) and diamines.

[0052] The polyamide block comprises at least one unit derived from the condensation of at least one lactam; at least one aminocarboxylic acid; or at least one diamine and at least one dicarboxylic acid.

[0053] In the symbol PA XY, as is customary, X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine residue (Cx diamine) containing x carbon atoms, and Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic diacid residue (Cy diacid) containing y carbon atoms.

[0054] In the symbol PA Z, Z represents the number of carbon atoms derived from an amino acid residue or a lactam residue.

[0055] The term "polyamide" encompasses both homopolymers and copolymers.

[0056] Unless otherwise stated, all percentages are weight (mass) percentages. It should also be noted that the expressions “between… and…” and “from… to…” used in this specification must be understood to include each of the specified limitations.

[0057] Polyamide block

[0058] Polyamide blocks are semi-crystalline polyamides. The term "semi-crystalline polyamide" refers to a class of polyamides that exhibit a combination of crystalline and amorphous regions in their molecular structure.

[0059] Relative to the total weight of the polyamide block, the polyamide block contains 30% to 75% by weight, preferably 30% to 70% by weight, and particularly 35% to 70% by weight, an aliphatic dicarboxylic acid (also called a "diacid") and / or a diamine comprising at least 36 (preferably 36 or 44, more preferably 36) carbon atoms. The weight percentage of the aliphatic dicarboxylic acid or diamine comprising at least 36 carbon atoms can be determined by differential scanning calorimetry (DSC) or nuclear magnetic resonance (NMR) analysis.

[0060] Aliphatic dicarboxylic acids or diamines comprising at least 36 carbon atoms can be components of monomer units or chain restrictors of polyamide blocks.

[0061] The term "chain limiter" refers to a molecule or functional group that terminates polymer chain growth during its synthesis. The use of such chain limiters allows for control over the molecular weight and length of the polymer chains in polyamide blocks.

[0062] Preferably, the polyamide block comprises unit X.36 or unit 36.Y, wherein:

[0063] - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms.

[0064] - 36 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 36 carbon atoms, and

[0065] - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms, or

[0066] Aliphatic dicarboxylic acids and / or diamines, comprising 36 carbon atoms, are chain restrictors for semi-crystalline polyamide blocks.

[0067] According to another embodiment, the polyamide block includes unit X.44 or unit 44.Y, wherein:

[0068] - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms.

[0069] - 44 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 44 carbon atoms, and

[0070] - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms, or

[0071] Aliphatic dicarboxylic acids and / or diamines, comprising 44 carbon atoms, are chain restrictors for semi-crystalline polyamide blocks.

[0072] The diacid containing 36 carbon atoms is sold by Cargill under the trademark Pripol® 1009.

[0073] Diacids containing 44 carbon atoms are sold by Cargill under the trademark Pripol® 2044. Diamines containing 36 carbon atoms are sold by Cargill under the trademark Priamine® 1075.

[0074] The polyamide blocks of the copolymers according to the present invention may include the following units:

[0075] - PA X36, PA X36 / X1Y1, PA X36 / Z, PA X44, PA X44 / X1Y1, PA X44 / Z;

[0076] - PA 36Y, PA 36Y / X2Y2, PA 36Y / Z, PA 44Y, PA 44Y / X2Y2, PA 44Y / Z;

[0077] - PA XY, which uses a diamine or diacid comprising 36 or 44 carbon atoms as a chain limiting agent; PA XY / Z, which uses a diamine or diacid comprising 36 or 44 carbon atoms as a chain limiting agent;

[0078] - PA Z, which uses a diamine or diacid containing 36 or 44 carbon atoms as a chain limiting agent.

[0079] - or its copolymers, wherein:

[0080] X is a straight-chain or branched aliphatic, alicyclic, or aromatic diamine, particularly those containing 2 to 44, preferably 2 to 36, carbon atoms, and more preferably those containing 10 to 36 carbon atoms.

[0081] Y is a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid, particularly those containing 4 to 44 carbon atoms, preferably those containing 6 to 36 carbon atoms.

[0082] Z is one or more α,ω-aminocarboxylic acids and / or one or more lactams containing 7 to 12 carbon atoms.

[0083] X1 and X2 are straight-chain or branched aliphatic, alicyclic, or aromatic diamines, particularly those containing 2 to 44, preferably 2 to 36, carbon atoms, and more preferably those containing 10 to 36 carbon atoms.

[0084] Y1 and Y2 are straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acids, particularly those containing 4 to 44 carbon atoms, preferably those containing 6 to 36 carbon atoms.

[0085] X1 is a diamine that is the same as or different from X, and Y1 is a diacid that is different from 36 or 44.

[0086] X2 is a diamine that is different from 36 or 44, and Y2 is a diacid that is the same as or different from Y.

[0087] The polyamide block containing an aliphatic dicarboxylic acid comprising at least 36 carbon atoms can be at least one of the following formulas: PA X36, PA X36 / X1Y1, PA X36 / Z, PA X44, PA X44 / X1Y1, PA X44 / Z.

[0088] In these formulas, X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine, particularly those containing 2 to 44, preferably 2 to 36, carbon atoms, and more preferably those containing 10 to 36 carbon atoms.

[0089] Preferably, X may be selected from: butanediamine (x=4); pentanediamine (x=5); hexanediamine (x=6); heptanediamine (x=7); octanediamine (x=8); nonanediamine (x=9); decanediamine (x=10); undecanediamine (x=11); dodecanediamine (x=12); tridecanediamine (x=13); tetradecanediamine (x=14); hexadecanediamine (x=16) and octadecanediamine (x=18); isomers of bis(4-aminocyclohexyl)methane (BACM), bis(3-methyl-4-aminocyclohexyl)methane (BMACM) and 2,2-bis(3-methyl-4-aminocyclohexyl)propane (BMACP); p-aminodicyclohexylmethane (PACM); isophorone diamine (IPDA); 2,6-bis(aminomethyl)norbornene (BAMN); and piperazine (Pip); and dimeric diamine.

[0090] The formula PAX36 / X1Y1 represents a copolyamide block, where X1 is a diamine that is the same as or different from X, and Y1 is a diacid that is different from 36. The formula PAX44 / X1Y1 represents a copolyamide block, where X1 is a diamine that is the same as or different from X, and Y1 is a diacid that is different from 44.

[0091] Y1 refers to a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid, especially those containing 4 to 18 carbon atoms, preferably those containing 6 to 18 carbon atoms.

[0092] Preferably, Y1 can be selected from succinic acid (y1=4), glutaric acid (y1=5), adipic acid (y1=6), pimelic acid (y1=7), octanoic acid (y1=8), azelaic acid (y1=9), sebacic acid (y1=10), undecanoic acid (y1=11), dodecanoic acid (y1=12), tridecanoic acid (y1=13), tetradecanoic acid (y1=14), hexadecanoic acid (y1=16), octadecanoic acid (y1=18), terephthalic acid, and isophthalic acid.

[0093] Advantageously, the unit 618, PA104, PA 109, PA 1010, PA 1012, PA 1013, PA 1014, PA 1016, PA 1018, PA 10T, PA 124, PA129, PA 1210, PA 1212, PA 1213, PA 1214, PA 1216, PA 1218, PA 12T, PA 366.

[0094] Formula PA X36 / Z represents a copolyamide block, where Z is a lactam or amino acid as described above. Formula PA X44 / Z represents a copolyamide block, where Z is a lactam or amino acid as described above.

[0095] Preferably, examples of unit Z include pyrrolidone (z=4), 2-piperidinone (z=5), heptanolactam (z=7), octanolactam (z=6), nonanolactam, decanolactam (z=10), undecanolactam (z=11), lauryllactam (z=12), 7-aminoheptanoic acid (z=7), 10-aminodecanoic acid (represented as 10, z=10), 11-aminoundecanoic acid (represented as 11, z=11), and 12-aminododecanoic acid (represented as 12, z=12).

[0096] Polyamide blocks containing aliphatic dicarboxylic acids comprising 36 carbon atoms can have the following formulas: PA 36Y, PA36Y / X2Y2, PA 36Y / Z. Polyamide blocks containing aliphatic dicarboxylic acids comprising 44 carbon atoms can have the following formulas: PA44Y, PA 44Y / X2Y2, PA 44Y / Z. In these formulas, Y represents a linear or branched aliphatic, alicyclic, or aromatic diacid, particularly those containing 2 to 44, preferably 2 to 36, carbon atoms, and more preferably those containing 10 to 36 carbon atoms.

[0097] Preferably, Y can be selected from succinic acid (y=4), glutaric acid (y=5), adipic acid (y=6), pimelic acid (y=7), octanoic acid (y=8), azelaic acid (y=9), sebacic acid (y=10), undecanoic acid (y=11), dodecanoic acid (y=12), tridecanoic acid (y=13), tetradecanoic acid (y=14), hexadecanoic acid (y=16), and octadecanoic acid (y=18), terephthalic acid and isophthalic acid, as well as dimerized fatty acids.

[0098] Formula PA 36Y / X2Y2 represents a copolyamide block, where X2 is a diamine different from 36, and Y2 is a diacid that is the same as or different from Y. Formula PA 44Y / X2Y2 represents a copolyamide block, where X2 is a diamine different from 44, and Y2 is a diacid that is the same as or different from Y.

[0099] X2 refers to a straight-chain or branched aliphatic, alicyclic, or aromatic diamine, particularly those containing 2 to 18 carbon atoms, preferably those containing 10 to 18 carbon atoms.

[0100] Preferably, X2 can be selected from: butanediamine (x2=4); pentanedanediamine (x2=5); hexanediamine (x2=6); heptanedanediamine (x2=7); octanediamine (x2=8); nonanediamine (x2=9); decanedanediamine (x2=10); undecanediamine (x2=11); dodecanediamine (x2=12); tridecanediamine (x2=13); tetradecanediamine (x2=14); hexadecanediamine (x2=16); and octadecanediamine. Alkanediamines (x2=18); isomers of bis(4-aminocyclohexyl)methane (BACM), bis(3-methyl-4-aminocyclohexyl)methane (BMACM) and 2,2-bis(3-methyl-4-aminocyclohexyl)propane (BMACP); p-aminodicyclohexylmethane (PACM); isophorone diamine (IPDA); 2,6-bis(aminomethyl)norbornene (BAMN); and piperazine (Pip).

[0101] Advantageously, the units 616, PA6.18, PA 636, PA 104, PA 109, PA 1010, PA 1012, PA 1013, PA 1014, PA 1016, PA 1018, PA1036, PA 10T, PA 1136, PA 124, PA 129, PA 1210, PA 12.12, PA 12.13, PA 1214, PA 1216, PA 1218, PA 1236, PA 12T.

[0102] Formula PA36Y / Z represents a copolyamide block, where Z is a lactam or amino acid as described above. Formula PA44Y / Z represents a copolyamide block, where Z is a lactam or amino acid as described above.

[0103] Preferably, examples of unit Z include pyrrolidone (z=4), 2-piperidinone (z=5), heptanolactam (z=7), octanolactam (z=6), nonanolactam, decanolactam (z=10), undecanolactam (z=11), lauryllactam (z=12), 7-aminoheptanoic acid (z=7), 10-aminodecanoic acid (represented as 10, z=10), 11-aminoundecanoic acid (represented as 11, z=11), and 12-aminododecanoic acid (represented as 12, z=12).

[0104] The polyamide block can also be a ternary polyamide, a tetrameric polyamide, or a pentadienyl polyamide, or a copolyamide having more than 5 different units. These units can be in the form of XY (diamine-diacid) or Z (lactam or amino acid), such as X36 / X1Y1 / Z1 / Z2, X36 / X1Y1 / X2Y2 / Z1, X36 / X1Y1 / X2Y2 / Z1 / Z2, 36Y / X1Y1 / Z1 / Z2, 36Y / X1Y1 / X2Y2 / Z1, 36Y / X1Y1 / X2Y2 / Z1 / Z2, X44 / X1Y1 / Z1 / Z2, X44 / X1Y1 / X2Y2 / Z1, X44 / X1Y1 / X2Y2 / Z1 / Z2, 44Y / X1Y1 / Z1 / Z2, 44Y / X1Y1 / X2Y2 / Z1, 44Y / X1Y1 / X2Y2 / Z1 / Z2.

[0105] Examples of copolyamides having two or more different units include PA 11 / 536, PA 11 / 1036, PA 11 / 636, PA 11 / 1236, PA 6 / 536, PA 6 / 1036, PA 6 / 636, PA 6 / 1236, PA 12 / 536, PA12 / 1036, PA 12 / 636, PA 5.36 / 10.36, PA 536 / 636, PA 536 / 1236, PA 1036 / 636, PA 1036 / 1236, PA 636 / 1236, PA 11 / 6 / 1236, PA 6 / 11 / 1036, PA 536 / 1036 / 6, and PA 12 / 536 / 636, PA11 / 544, PA 11 / 1044, PA 11 / 644, PA 11 / 1244, PA 6 / 544, PA 6 / 1044, PA 6 / 644, PA 6 / 1244, PA 12 / 544, PA 12 / 1044, PA 12 / 644, PA 544 / 1044, PA 544 / 644, PA 544 / 1244, PA 1044 / 644, PA 1044 / 1244, PA 644 / 1244, PA 11 / 6 / 1244, PA 6 / 11 / 1044, PA 544 / 1044 / 6 and PA 12 / 544 / 644, preferably PA 11 / 1036.

[0106] According to another embodiment, an aliphatic dicarboxylic acid and / or diamine comprising at least 36 carbon atoms (preferably 36 carbon atoms or 44 carbon atoms, more preferably 36 carbon atoms) can be present as a chain restrictor for the polyamide block. The polymer chain can be described as follows: -36-PA-36 or -44-PA-44-.

[0107] According to this embodiment, the polyamide block may include PA XY (diamine diacid), PA Z (lactam or amino acid), or copolymers thereof, wherein X, Y, and Z are as defined above.

[0108] Preferably, the polyamide blocks are selected from PA 11, PA 12, PA 536, PA 1036, PA 636, PA1136, PA1236, PA 366, PA 11 / 1036, PA 1012 / 1036, PA 1010 / 1036, PA 610 / 636, PA 612 / 636, PA613 / 636, PA 69 / 636, PA 544, PA 1044, PA 644, PA 1144, PA 1244, PA 446, PA 11 / 1044, PA1012 / 1044, PA 1010 / 1044, PA 610 / 644, PA 612 / 644, PA 613 / 644, PA 69 / 644. The repeating units of the polyamide blocks of the copolymers according to the present invention have an average carbon content of 7 or greater.

[0109] The term "average carbon content of repeating units" refers to the average number of carbon atoms in each repeating unit present in the polyamide block of the copolymer, obtained by weighting the repeating units relative to the total amount of polyamide blocks. For example, for PA X / Y as defined above, comprising a mol% PA X and b mol% PA Y (a%+b% represents 100 mol% polyamide), the average carbon content is: (a × X + b × Y) / 100. When the polyamide block comprises a single repeating unit, such as in the case of the PA X block or PA XY block as defined above, assuming the polyamide repeating unit contains only one amide functional group in a known manner, the average carbon content of the repeating units of the polyamide block is equal to the number of carbon atoms in the repeating unit. In the case of the PA X block, the number of carbon atoms in the repeating unit is X. In the case of the PA XY block, the number of carbon atoms in the repeating unit is (X+Y) / 2, because the unit XY includes two amide functional groups.

[0110] Preferably, the average carbon content of the repeating units of the polyamide blocks of the copolymer according to the invention is 8 to 14, more preferably 8 to 25, and most preferably 10 to 25.

[0111] The number-average molar mass of the polyamide block in the copolymer according to the invention is preferably from 400 g / mol to 20,000 g / mol, more preferably from 500 g / mol to 10,000 g / mol, and even more preferably from 600 g / mol to 2,500 g / mol. In some embodiments, the number-average molar mass of the rigid polyamide blocks in the copolymer is 400 g / mol to 500 g / mol, or 500 g / mol to 1000 g / mol, or 1000 g / mol to 1500 g / mol, or 1500 g / mol to 2000 g / mol, or 2000 g / mol to 2500 g / mol, or 2500 g / mol to 3000 g / mol, or 3000 g / mol to 3500 g / mol, or 3500 g / mol to 4000 g / mol, or 4000 g / mol to 5000 g / mol, or 5000 g / mol to 6000 g / mol, or 6000 g / mol to 7000 g / mol, or 7000 g / mol to 8000 g / mol, or 8000 g / mol to 9000 g / mol, or 9000 g / mol. g / mol to 10000 g / mol, or 10000 g / mol to 11000 g / mol, or 11000 g / mol to 12000 g / mol, or 12000 g / mol to 13000 g / mol, or 13000 g / mol to 14000 g / mol, or 14000 g / mol to 15000 g / mol, or 15000 g / mol to 16000 g / mol, or 16000 g / mol to 17000 g / mol, or 17000 g / mol to 18000 g / mol, or 18000 g / mol to 19000 g / mol, or 19000 g / mol to 20000 g / mol.

[0112] The number-average molar mass is determined by the content of the chain limiter. It can be calculated using the following equation:

[0113] M n =n 单体 × MW 重复单元 / n 链限制剂 + MW 链限制剂 .

[0114] In this formula, n 单体 n represents the number of moles of the monomer. 链限制剂 Indicates the number of moles of excess chain restrictor (e.g., diacid), MW 重复单元 This represents the molar mass of the repeating unit, and MW 链限制剂This indicates the molar mass of the excess limiting agent (e.g., diacid). The number-average molar mass of the polyamide block can be measured by gel permeation chromatography (GPC) before block copolymerization. The number-average molar mass of the polyol block can be determined by measuring the number of hydroxyl groups.

[0115] Flexible Block

[0116] The term "flexible block" refers to a block having a glass transition temperature (Tg) less than or equal to 0 °C. The glass transition temperature can be determined by differential scanning calorimetry according to standard ISO 11357-2 Plastics—Differential scanning calorimetry (DSC) Part 2.

[0117] The flexible blocks of the copolymer contain blocks derived from polyethylene glycol (PEG).

[0118] In some embodiments, the flexible blocks of the copolymer according to the invention may consist of blocks derived from PEG.

[0119] Alternatively, in addition to the PEG-derived blocks, the flexible blocks of the copolymer may contain at least one other block.

[0120] In some embodiments, the flexible blocks of the copolymer comprise at least 50%, preferably at least 60%, or even more preferably at least 80% by weight of PEG-derived blocks relative to the total weight of the flexible blocks.

[0121] In addition to blocks derived from PEG, the flexible blocks of the copolymer may also include one or more other polyethers and / or polyesters and / or polysiloxanes and / or polydimethylsiloxane (or PDMS) and / or polyolefins and / or polycarbonates. For example, possible flexible blocks are described in French patent application FR 2941700 A1, page 32, line 3 to page 33, line 8; page 34, line 16 to page 37, line 13; and page 38, lines 6 to 23.

[0122] Preferably, the other block is a polyether block other than a block derived from PEG; and / or a polyester block.

[0123] The copolymer may include several types of polyethers in its chain, other than blocks derived from PEG, and the corresponding coethers may be block coethers or random coethers.

[0124] As for polyether blocks other than those derived from PEG, references may be made to blocks derived from propylene oxide units (PPG, polypropylene glycol), blocks derived from polytrimethylene glycol ether units (PO3G, polytrimethylene glycol), blocks derived from tetramethylene glycol units (also known as polytetrahydrofuran), or any combination thereof. Particularly preferred are polyether blocks derived from polypropylene glycol and / or polytetrahydrofuran.

[0125] Blocks obtained by oxyethylation of bisphenols (e.g., bisphenol A) can also be used as polyethers other than PEG. These oxyethylated block products are described in particular in EP 613919.

[0126] Polyether blocks can also be composed of ethoxylated primary amines. As examples of ethoxylated primary amines, products having the following formula can be mentioned:

[0127] H-(OCH2CH2) m -N((CH2) x CH3)-(CH2CH2O n -H

[0128] Where m and n are integers between 1 and 20, and x is an integer between 8 and 18. These products are available, for example, from Arkema under the trademark Noramox® and from Clariant under the trademark Genamin®.

[0129] The flexible block may also include a polyoxyethylene polyether block with an NH2 chain terminus, which can be obtained by cyanoacetylation of an aliphatic α,ω-dihydroxylated polyoxyethylene block known as a polyether diol. More specifically, commercial products such as Jeffamine or Elastamine (e.g., Jeffamine® D400, D2000, ED 2003, XTJ 542, which are commercial products from Huntsman Corporation and are also described in JP 2004 / 346274, JP 2004 / 352794 and EP1482011) can be used.

[0130] The polyether diol block can be used in its unmodified form and copolymerized with a polyamide block having a carboxyl end group, or it can be amination to convert it into a polyether diamine and condensed with a polyamide block having a carboxyl end group.

[0131] The number-average molar mass of the flexible block is preferably from 200 g / mol to 6000 g / mol, more preferably from 500 g / mol to 3000 g / mol, and even more preferably from 600 g / mol to 2000 g / mol. In some embodiments, the number-average molar mass of the flexible block is 200 g / mol to 500 g / mol, or 500 g / mol to 800 g / mol, or 800 g / mol to 1000 g / mol, or 1000 g / mol to 1500 g / mol, or 1500 g / mol to 2000 g / mol, or 2000 g / mol to 2500 g / mol, or 2500 g / mol to 3000 g / mol, or 3000 g / mol to 3500 g / mol, or 3500 g / mol to 4000 g / mol, or 4000 g / mol to 4500 g / mol, or 4500 g / mol to 5000 g / mol, or 5000 g / mol to 5500 g / mol, or 5500 g / mol to 6000 g / mol.

[0132] The number-average molar mass of the flexible block can be measured as described above by gel permeation chromatography (GPC) prior to block copolymerization. The number-average molar mass of the polyol block can be determined by measuring the number of hydroxyl groups.

[0133] copolymer

[0134] The copolymers according to the invention can be linear or branched copolymers. For example, the copolymer can be a branched copolymer, wherein the branches are formed by bonding the polyamide blocks of the copolymer with polyol residues with a functionality greater than 2 (i.e., the polyols include at least three hydroxyl groups).

[0135] The melting point of the copolymer of the present invention is equal to or higher than 80°C, preferably higher than 80°C. Advantageously, the melting point of the copolymer of the present invention is equal to or higher than 85°C, preferably equal to or higher than 90°C, and more preferably equal to or higher than 100°C. According to ISO 11357-3 Differential Scanning Calorimetry (DSC) Part 3, the melting point can be determined by differential scanning calorimetry at a rate of 20°C / min during the heating phase.

[0136] The copolymers according to the invention may include copolymers containing three, four (or even more) different blocks selected from those described herein, provided that the blocks include at least polyamide blocks and polyethylene glycol-derived blocks.

[0137] For example, the copolymer according to the invention can be a segmented block copolymer (or “triblock” copolymer) comprising three different types of blocks, which is produced by the condensation of the aforementioned blocks. The triblock can be, for example, a copolymer comprising a polyamide block, a flexible block derived from PEG, and a polyester block; or a copolymer comprising a polyamide block, a flexible block derived from PEG, and a block derived from PTMG.

[0138] In a particularly advantageous manner, the copolymers according to the invention comprise or consist of polyamide blocks of PA 11, PA10.36, PA 11 / 1036 or PA 366, flexible blocks derived from PEG, or any mixture or combination thereof, provided that, relative to the total weight of the polyamide blocks, the polyamide blocks contain 30% to 75% by weight, preferably 30% to 70% by weight, of an aliphatic dicarboxylic acid or diamine comprising 36 carbon atoms.

[0139] In the context of this invention, copolymers particularly preferred are copolymers comprising (or composed of) the following blocks:

[0140] - PA 11 and PEG-derived blocks, wherein PA 11 contains C36 dicarboxylic acid as a chain restrictor;

[0141] - PA 1036 and PEG-derived blocks;

[0142] - PA 11 / 1036 and blocks derived from PEG;

[0143] - PA 366 and PEG-derived blocks;

[0144] - PA 11 and PEG-derived blocks, wherein PA 11 contains C44 dicarboxylic acid as a chain restrictor;

[0145] - PA 1044 and blocks derived from PEG;

[0146] - PA 11 / 1044 and blocks derived from PEG;

[0147] - PA 446 and blocks derived from PEG.

[0148] In these copolymers, the polyamide blocks contain 30% to 75% by weight, preferably 30% to 70% by weight, and particularly 35% to 70% by weight, of C36 dicarboxylic acid (in the case of PA 11 / PEG (as a chain restrictor), PA 1036 / PEG, PA 11 / 1036 / PEG) or C36 diamine (in the case of PA 365 / PEG) relative to the total weight of the polyamide blocks.

[0149] Advantageously, the copolymers PA 1036 / PEG and PA 11 / 1036 / PEG may also include a chain restrictor, preferably C36 dicarboxylic acid. Similarly, the polymer PA 365 / PEG may also include a chain restrictor, preferably C36 dicarboxylic acid.

[0150] In these copolymers, the polyamide blocks contain 30% to 75% by weight, preferably 30% to 70% by weight, and particularly 35% to 70% by weight, of C44 dicarboxylic acid (in the case of PA 11 / PEG (as a chain restrictor), PA 1044 / PEG, PA 11 / 1044 / PEG) or C44 diamine (in the case of PA 445 / PEG) relative to the total weight of the polyamide blocks.

[0151] Advantageously, the copolymers PA 1044 / PEG and PA 11 / 1044 / PEG may also include a chain restrictor, preferably C36 dicarboxylic acid. Similarly, the polymer PA 445 / PEG may also include a chain restrictor, preferably C44 dicarboxylic acid. In the copolymers according to the invention, the weight percentage of polyamide blocks is 15% to 60%, preferably 20% to 50%, more preferably 30% to 50%, relative to the total weight of the copolymer, and the weight percentage of flexible blocks is 40% to 85%, preferably 30% to 60%, more preferably 35% to 60%, relative to the total weight of the copolymer.

[0152] Preferably, the weight percentage of the flexible block relative to the total weight of the copolymer is 40% to 85%, more preferably 50% to 80%, and even more preferably 50% to 70%.

[0153] The weight ratio of polyamide blocks to flexible blocks in the copolymer can be determined by DSC or NMR analysis.

[0154] In the copolymer according to the invention, the number-average molecular weight of the polyamide block can be from 400 g / mol to 20000 g / mol, preferably from 500 g / mol to 10000 g / mol, more preferably from 600 g / mol to 2500 g / mol, and the number-average molecular weight of the flexible block can be from 200 g / mol to 6000 g / mol, preferably from 500 g / mol to 3000 g / mol, more preferably from 600 g / mol to 2000 g / mol.

[0155] Synthesis of copolymers

[0156] The present invention also relates to a method for preparing the copolymers described above.

[0157] In a generally known manner, polymers containing polyamide blocks and flexible blocks can be prepared either by a two-step preparation method (including a first step, synthesizing polyamide blocks, and then a second step, condensing polyamide blocks and flexible blocks) or by a one-step preparation method.

[0158] In some embodiments, the copolymer is prepared according to a two-step method. This method includes the following steps:

[0159] - Polyamide blocks are synthesized from polyamide precursors.

[0160] - Add flexible blocks, and

[0161] - To cause polyamide blocks and flexible blocks to condense.

[0162] Alternatively, the copolymers according to the invention can be prepared according to a one-step method, comprising mixing a flexible block with a polyamide precursor and a limiting chain diacid.

[0163] A general method for the two-step preparation of copolymers containing polyamide blocks and flexible polyether blocks with ester bonds between PA and PE blocks (also known as PEBA, or polyether-block-amide according to IUPAC) is known (i.e., the first step is the synthesis of the polyamide blocks, and the second step is the condensation of the polyamide and flexible polyether blocks), and is described, for example, in FR2846332. A general method for the preparation of PEBA copolymers with amide bonds between PA and PE blocks is known, and is described, for example, in EP 1482011. Flexible polyether blocks can also be mixed with polyamide precursors and diacids with restricted chains to prepare polymers containing polyamide blocks and flexible polyether blocks with randomly distributed units (one-step method).

[0164] Regardless of the preparation method (one-step or two-step), copolymers with polyamide blocks and flexible blocks are produced by polycondensation of polyamide blocks with reactive ends and flexible blocks with reactive ends, for example, especially the following polycondensation:

[0165] 1) Polyamide blocks with diamine chain ends and flexible blocks with dicarboxylic acid chain ends;

[0166] 2) Polyamide blocks with dicarboxylic acid chain ends and flexible blocks with diamine chain ends, the flexible blocks being obtained, for example, by cyanoethylation and hydrogenation of an aliphatic α,ω-dihydroxylated polyoxyethylene block called polyether diol;

[0167] 3) Polyamide blocks with dicarboxylic acid chain ends and polyether diols, in this specific case, yield a polyether ester amide.

[0168] Polyamide blocks with dicarboxylic acid chain ends are derived, for example, from the condensation of a polyamide precursor in the presence of a limiting dicarboxylic acid. Polyamide blocks with diamine chain ends are, for example, from the condensation of a polyamide precursor in the presence of a limiting diamine.

[0169] When the copolymer is a branched copolymer, it can be prepared by adding one or more polyols containing at least three hydroxyl groups as branching agents during its synthesis. In the one-step or two-step method described above, the polyol is added together with the polyamide precursor. Advantageously, the amount of polyol added ranges from 0.01% to 10% by weight, preferably from 0.01% to 5% by weight, and more preferably from 0.05% to 0.5% by weight, relative to the total weight of the polyol, polyamide precursor, and flexible blocks. The addition of a polyol containing at least three hydroxyl groups creates bridging bonds that link the polyamide blocks of the copolymer together, preferably through ester bonds. The polyol can be, in particular:

[0170] - Monomeric polyols, especially monomeric aliphatic triols such as glycerol, trimethylolpropane, pentaerythritol, and / or

[0171] - Polymer polyols, particularly triols containing polyether chains, polycaprolactone triols, and mixed polyether-polyester polyols containing at least three hydroxyl groups.

[0172] Advantageously, the polyol is selected from: pentaerythritol, trimethylolpropane, trimethylolethane, hexanetriol, diglycerol, methyl glucoside, tetraethanolamine, sorbitol, dipentaerythritol, cyclodextrin, polyether polyols comprising at least three hydroxyl groups, and mixtures thereof. The weight-average molar mass of the polyol is preferably not greater than 3000 g / mol, more preferably not greater than 2000 g / mol.

[0173] Composition

[0174] The present invention also relates to a composition comprising at least one copolymer as described above. The compositions of the present invention further comprise at least one additive selected from colorants, UV stabilizers, anti-aging agents, antioxidants, fluidizing agents, anti-abrasion agents, release agents, stabilizers, plasticizers, impact modifiers, surfactants, brighteners, fillers, fibers, waxes, and mixtures thereof.

[0175] In some embodiments, the composition may include, relative to the total weight of the composition:

[0176] - 70% to 99.99% by weight of the copolymers described above, and

[0177] - 0.01% to 30% by weight of one or more of these additives.

[0178] membrane

[0179] The present invention also relates to the use of a copolymer or composition as described above as a membrane for gas separation.

[0180] The present invention also relates to a membrane (or thin film) for gas separation, comprising the copolymers or compositions described above.

[0181] The term "membrane" refers to any layer, including membranes in the form of flat membranes and membranes in the form of hollow fibers.

[0182] The membrane can be a gas separation membrane used to recover greenhouse gases, particularly CO2. Gas separation can include separating CO2 from N2 in post-combustion processes.

[0183] The thickness of the membrane according to the invention is preferably from 0.1 µm to 500 µm, more preferably from 0.1 µm to 250 µm. Advantageously, the thickness of the membrane is less than 20 µm, and more advantageously less than 10 µm. For example, the membrane thickness can be 0.1 μm to 0.5 μm, or 0.5 μm to 1 μm, or 1 μm to 2 μm, or 2 μm to 5 μm, or 5 μm to 10 μm, or 10 μm to 20 μm, or 20 μm to 30 μm, or 30 μm to 40 μm, or 40 μm to 50 μm, or 50 μm to 60 μm, or 60 μm to 70 μm, or 70 μm to 80 μm, or 80 μm to 90 μm, or 90 μm to 100 μm, or 100 μm to 200 μm, or 200 μm to 300 μm, or 300 μm to 400 μm, or 400 μm to 500 μm. The membrane thickness can be determined according to conventional methods known in the art. For example, high-resolution images of the cross-section of the hollow fiber membrane can be captured using an optical microscope or an electron microscope, and the thickness can be measured directly from the image using conventional image analysis software.

[0184] In some embodiments, the membrane is substantially composed of the copolymers or compositions described above, or is composed of the copolymers or compositions described above.

[0185] The membrane may also include one or more additives selected from the following: UV stabilizers, crosslinking agents, pigments, metal oxides, zeolites, flame retardants, UV protectants, optical brighteners, heat stabilizers, lubricants, antioxidants, flow improvers, fluidity improvers, film-forming agents, fillers, film-forming aids, resins, semi-crystalline polymers, preservatives, antibacterial reinforcing agents, fibers (such as glass fibers), fillers (such as talc), colorants, anti-aging agents, antioxidants, anti-wear agents, stabilizers, plasticizers, impact modifiers, surfactants, brighteners, waxes, and mixtures thereof, wherein the mass content of the additives is preferably from 0.01% to 30% by weight relative to the total weight of the membrane.

[0186] In some embodiments, the membrane may comprise two or more copolymers as described above or two or more compositions as described above.

[0187] The membrane according to the invention can be a composite membrane, i.e., a membrane comprising at least one polymer layer as described above deposited on at least one porous, microporous or nanoporous support layer (such as nonwoven polypropylene or any polymer framework).

[0188] Methods for preparing membranes

[0189] The film according to the invention can be prepared in a known manner by any melting method (e.g., by flat film extrusion (“extrusion casting”) or by extrusion coating on a carrier) or by a solvent method (e.g., by deposition by a solvent / evaporation method (“solvent casting” or “spinning method”).

[0190] The present invention therefore relates to a method for preparing the membrane as described above.

[0191] The method includes the following steps:

[0192] - Supply of copolymers or compositions as described above.

[0193] - Dissolve the copolymer or composition in a solvent to form a solution.

[0194] - Deposit the solution onto the substrate, and

[0195] - Evaporate the solvent.

[0196] The membrane can be manufactured by a method including the following steps:

[0197] - Supply copolymers as described above;

[0198] - Melt copolymer;

[0199] - Formation of a molten copolymer film;

[0200] - To cure the film.

[0201] When the resulting film is in the form of a flat film, the above-mentioned methods by solvent casting or extrusion casting can be used advantageously.

[0202] When the membrane is a composite membrane, the polymer layer can be deposited on the support layer by extrusion coating, extrusion lamination, adhesive lamination, deposition by solvent / evaporation ("solvent casting"), atomization ("spraying"), welding or sealing.

[0203] The present invention relates to another method for preparing the membrane as described above.

[0204] The method includes the following steps:

[0205] - Supply a polymer solution comprising a copolymer or composition as described above dissolved in a solvent.

[0206] - Supply core fluid,

[0207] - The polymer solution and core liquid are co-extruded downwards into the coagulation bath, and

[0208] - Recover the membrane that has solidified in the coagulation bath.

[0209] - The recovered membrane is dried by solvent exchange or freeze drying.

[0210] Preferably, the method includes the following steps:

[0211] a) Supply at least one polymer solution comprising a copolymer as defined in claims 1 to 8 dissolved in a solvent, wherein the solvent is selected from N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, triethyl phosphate, dihydroglucanone, triethylene glycol diacetate, 1-butylpyrrolidone-2-one, tetrahydrofuran (THF), 2-methyltetrahydrofuran, and mixtures thereof;

[0212] b) Supply of core fluid,

[0213] c) Preferably, at a temperature of 15°C to 80°C, the at least one polymer solution and the core liquid are co-extruded downwards into a coagulation bath, wherein the polymer solution completely surrounds the core liquid, and

[0214] d) Recover the asymmetric hollow fiber membrane solidified in the coagulation bath, and

[0215] e) The recovered asymmetric hollow fiber membrane is dried by solvent exchange or freeze drying.

[0216] This method can be advantageously used when the resulting membrane is in the form of hollow fibers.

[0217] Example

[0218] The following examples illustrate the present invention but do not limit it.

[0219] Preparation of copolymer compositions

[0220] A composition comprising a copolymer containing polyamide blocks and flexible PEG blocks, and additives, is prepared according to the composition shown in the table below.

[0221] A11 refers to 11-aminoundecanoic acid.

[0222] DA10 refers to sebacic acid.

[0223] DC36 refers to a diacid containing 36 carbon atoms sold by Cargill under the trademark Pripol® 1009.

[0224] PEG refers to polyethylene glycol sold by BASF under the trademark Pluriol® E1500.

[0225] Irganox® 1010 is an antioxidant sold by BASF.

[0226] Zr(OBu)4 is a catalyst.

[0227] PEBA No. 1 and PEBA No. 2 correspond to the copolymers of the present invention.

[0228] Table 1 below shows the inputs, expressed in grams, for each reactant:

[0229]

[0230] Table 2 below shows the characterization of the PEBA copolymers:

[0231]

[0232] In Table 2:

[0233] Mn-PA corresponds to the number-average molecular weight of polyamide blocks.

[0234] Mn-PE corresponds to the number-average molecular weight of polyethylene glycol (PEG).

[0235] C36 / PA corresponds to the weight ratio of C36 aliphatic dicarboxylic acid or diamine to the total weight of polyamide blocks.

[0236] Tm corresponds to the melting point (°C) of the copolymer.

[0237] Membrane preparation

[0238] Flat membranes were prepared by solvent casting using PEBA No.1 and PEBA No.2.

[0239] Specifically, a 5 wt% polymer solution was dissolved in chloroform for 24 h at room temperature. The solution was filtered through a 0.45 μm filter and cast into glass petri dishes to obtain a flat membrane; the membrane thickness was 48 μm for PEBA 1 and 88 μm for PEBA 2.

[0240] At room temperature, under a flow of N2, the solvent is evaporated in a container in a solvent-saturated atmosphere for 24 hours, and then evaporated again under a vacuum at 50ºC for 24 hours.

[0241] The resulting membrane can be easily removed from the culture dish by peeling.

[0242] It has been confirmed that PEBA No.1 and PEBA No.2 exhibit good solubility in organic aprotic solvents (such as NMP and DMAc), while being insoluble in chemicals or non-solvents used for membrane washing (e.g., methanol, acrylonitrile, dimethoxymethane, hexane, and water).

[0243] The membranes made from copolymers PEBA 1 and PEBA 2 were compared with membranes made from different materials.

[0244] PEBA 3 is made from PA6 / PEG and does not contain dimer fatty acids or dimer fatty diamines that contain 36 carbon atoms.

[0245] CA is a material made from cellulose acetate (Mw = 100000 g / mol) supplied by Sigma Aldrich.

[0246] PS is polysulfone supplied by Solvay under the trade name Udel® P-3500.

[0247] P84 is a copolyimide supplied by Ensinger Sintimid GmbH, which is made from 3,3',4,4'-benzophenone tetracarboxylic dianhydride copolyimide with 80% methylphenylenediamine and 20% methylenediamine.

[0248] result

[0249] Permeability assessment

[0250] The term “permeability” in membranes refers to a measure of how easily a substance (in this application, a gas) can pass through a membrane, expressed in Barrer terms, which indicates the rate at which a gas driven by a given pressure at a given temperature flows through a membrane of a certain thickness.

[0251] Specifically, permeability (in barre kilometres) can be calculated using the following formula:

[0252] 10 -10 × ((cm 3 STP × cm) / (s × cm 2 × cmHg))

[0253] In the formula, “cm 3 STP "cm" corresponds to a standard cubic centimeter (a unit of gas volume), representing the number (mol) of gas molecules occupying one cubic centimeter at standard temperature and pressure, calculated using the ideal gas law. "cm" corresponds to the thickness of the membrane whose permeability is being evaluated. Therefore, "cm" 3 STP / (cm 2 × s 1 ) (cm 3 STP ·cm -2 s -1 The value ) corresponds to the gas flux through the membrane, and cmHg corresponds to the pressure drop across the material.

[0254] The gas flux through the membrane at 35°C and 3 bar can be determined using a gas permeability method. Specifically, the membrane can be placed in a permeation cell, and the upper surface of the membrane can be flushed with a test gas, while the lower surface can be flushed with a carrier gas. The gas flow diffusing through the membrane to the lower part can be analyzed by gas chromatography.

[0255] Selective assessment

[0256] The A / B selectivity of the membrane corresponds to the ratio of the membrane's permeability to gas A to its permeability to another gas B, measured at a temperature of 35°C and a pressure of 3 bar (absolute pressure).

[0257] The membrane's permeability and selectivity properties were tested, and the results are as follows:

[0258]

[0259] It is important to note that the membrane according to the invention has excellent permeability and good selectivity for CO2 relative to N2 and H2, which suggests that this polymer could be a better candidate for post-combustion CO2 capture.

Claims

1. A thermoplastic copolymer containing semi-crystalline polyamide blocks and flexible blocks, wherein: - Relative to the total weight of the polyamide blocks, the semi-crystalline polyamide blocks contain 30% to 75% by weight, preferably 30% to 70% by weight, of an aliphatic dicarboxylic acid and / or diamine comprising at least 36 carbon atoms, and the repeating units of the polyamide blocks of the copolymer have an average carbon content of greater than or equal to 7. - The flexible block comprises blocks derived from polyethylene glycol, and - The polyamide block accounts for 15% to 60% by weight relative to the total weight of the copolymer, and - The flexible block comprises 40% to 85% by weight relative to the total weight of the copolymer. - The melting point of the copolymer of the present invention is equal to or higher than 80°C, preferably higher than 80°C.

2. The copolymer according to claim 1, wherein, The polyamide block comprises unit X.36 or unit 36.Y, wherein: - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms. - 36 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 36 carbon atoms, and - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms.

3. The copolymer according to claim 1, wherein, The polyamide block comprises unit X.44 or unit 44.Y, wherein: - X represents a straight-chain or branched aliphatic, alicyclic, or aromatic diamine containing x carbon atoms. - 44 indicates an aliphatic dicarboxylic acid or aliphatic diamine containing 44 carbon atoms, and - Y represents a straight-chain or branched aliphatic, alicyclic, or aromatic dicarboxylic acid containing y carbon atoms.

4. The copolymer according to claim 1, wherein, The aliphatic dicarboxylic acid and / or diamine comprising at least 36 carbon atoms, preferably 36 carbon atoms or 44 carbon atoms, more preferably 36 carbon atoms, are chain restrictors of the semi-crystalline polyamide blocks.

5. The copolymer according to any one of claims 1 to 4, wherein, The polyamide blocks include the following units: PA11, PA12, PA536, PA1036, PA636, PA1136, PA1236, PA366, PA11 / 1036, PA1012 / 1036, PA1010 / 1036, PA610 / 636, PA612 / 636, PA613 / 636, PA69 / 636, PA544, PA1044, PA644, PA1144, PA1244, PA446, PA11 / 1044, PA1012 / 1044, PA1010 / 1044, PA610 / 644, PA612 / 644, PA613 / 644, PA69 / 644.

6. The copolymer according to any one of claims 1 to 5, wherein: - The polyamide block accounts for 20% to 50% by weight, more preferably 30% to 50% by weight, relative to the total weight of the copolymer, and - The weight percentage of the flexible block relative to the total weight of the copolymer is 50% to 80% by weight, more preferably 50% to 70% by weight.

7. The copolymer according to any one of claims 1 to 6, wherein: - The number-average molecular weight of the polyamide blocks is 400 g / mol to 20000 g / mol, preferably 500 g / mol to 10000 g / mol, more preferably 600 to 2500 g / mol, and - The number-average molecular weight of the flexible block is 200 g / mol to 6000 g / mol, preferably 500 g / mol to 3000 g / mol, and more preferably 600 g / mol to 2000 g / mol.

8. A composition comprising: - At least one copolymer according to any one of claims 1 to 7; as well as - At least one additive selected from colorants, UV stabilizers, anti-aging agents, antioxidants, fluidizing agents, anti-abrasion agents, release agents, stabilizers, plasticizers, impact modifiers, surfactants, brighteners, fillers, fibers, waxes, and mixtures thereof.

9. Use of a copolymer as described in any one of claims 1 to 7 or the composition as described in claim 8 as a membrane for gas separation.

10. A membrane for gas separation, comprising a copolymer as described in any one of claims 1 to 7 or a composition as described in claim 8.

11. The membrane according to claim 10, wherein, The membrane has a thickness of 0.05 µm to 500 µm, preferably 0.10 µm to 250 µm, more preferably less than 20 µm, and even more preferably less than 10 µm.

12. A method for preparing the membrane as described in claim 10 or 11, comprising the following steps: - Supply of the copolymers as described in claims 1 to 7 or the composition as described in claim 8. - Dissolve the copolymer or the composition in a solvent to form a solution. - Deposit the solution onto the substrate, and - Evaporate the solvent.

13. A method for preparing the membrane as described in claim 10 or 11, comprising the following steps: - Supply a polymer solution comprising a copolymer as described in claims 1 to 8 or a composition as described in claim 9 dissolved in a solvent. - Supply core fluid, - The polymer solution and the core liquid are co-extruded downwards into a coagulation bath, and - Recover the film that has solidified in the coagulation bath. - The recovered membrane is dried by solvent exchange or freeze-drying.

Images