Porous membrane comprising a biphenol-co-dianhydrohexitol sulfone copolymer

Abstract

The invention relates to a porous membrane, particularly intended for use in medical and / or water filtration applications, comprising at least one biphenol-co-dianhydrohexitol copolymer (P1). The porous membrane may be selected from hollow fibers, flat membranes, or a support or selective porous layer in a thin-film composite membrane. The porous membrane may be asymmetric. The porous membrane may be used for hemodialysis, desalination and / or water filtration, such as reverse osmosis, ultrafiltration or nanofiltration. The invention further relates to a polymeric composition comprising a biphenol-co-dianhydrohexitol copolymer (P1) and a PSSU polymer (P2), and to a method for improving the solubility and compatibility of a PSSU polymer (P2) in a polymeric dope solution particularly comprising dimethylformamide or dimethylacetamide or dimethyl isosorbide as solvent, by adding a biphenol-co-dianhydrohexitol copolymer (P1).

Description

- 1 - SSPU 2024 / 046Porous membrane comprisinga biphenol-co-dianhydrohexitol sulfone copolymer

[0001] RELATED APPLICATIONS

[0002] This application claims priority to U.S. application No. 63 / 738217 filed on December 23, 2024 and to European application No. 25155957.1 filed on February 5, 2025, the entire content of these applications being incorporated herein by reference for all purposes.

[0003] TECHNICAL FIELD

[0004] The present invention relates to a porous membrane, particularly intended for use in medical and / or water filtration applications, comprising at least one biphenol-co- dianhydrohexitol copolymer.

[0005] BACKGROUND

[0006] Polyarylethersulfone [“PAES”], a class of thermoplastic polymers, is a dominant polymeric material in the production of membranes for separation technology due to low cost and ease of processing, thermal and chemical stability. Their chemical, thermal, and mechanical resistance, combined with excellent hydrolytic stability and relatively inexpensive production costs, make it ideal for widespread use in fabrication of porous membranes.

[0007] Porous membrane is a thin object, the key property of which is its ability to control the permeation rate of chemical species through itself. This feature is exploited in applications like separation applications (water and gas). Porous hollow-fiber polymeric membranes are employed in many applications such as hemodialysis, ultrafiltration, nanofiltration, reverse osmosis, gas separation, microfiltration, desalination via membrane distillation, and pervaporation. For many of these applications, membranes with optimal selectivity as well as chemical, thermal and mechanical stability are desirable.

[0008] Polysulfone (PSF or PSU) and polyethersulfone (PES) are widely used materials for membrane preparation whereas polyphenylsulfone (PPSU) is a more recent polymer which features superior properties compared with the more frequently applied PSU and PES. See for example Hydrophilic poly(phenylene sulfone) membranes for ultrafiltration, Separation and Purification Technology vol. 250 (2020) 117107 ; Effect of Polyphenylsulfone and Polysulfone Incompatibility on the Structure and Performance of Blend Membranes for Ultrafiltration, Materials vol. 14 (2021) 5740;Recent Advancements in Polyphenylsulfone Membrane Modification Methods for Separation Applications, Membranes vol. 12 (2022) 247.- 2 - SSPU 2024 / 046

[0009] PPSU shows better impact strength than PSF and PES. It also has higher chemical resistance particularly to cleaning and disinfecting agents and a very low rate of water absorption (higher hydrophobicity), making it suitable for applications involving superheated steam sterilization and alkali washing. PPSU is remarkable for good dimensional stability and excellent resistance to high-energy radiation and heat. All these properties make PPSU a promising candidate for design of novel membranes.

[0010] To date, the use of PPSU has been studied for the development of membranes for ultrafiltration, nanofiltration, organic solvent nanofiltration, pervaporation, gas separation, membrane substrate for thin film composite membranes for forward osmosis, and proton-exchange membrane for fuel cells. PPSU membranes were revealed to be effective in water treatment: heavy metal, toxic dyes, humic acids removal from aqueous solutions, and decontamination of arsenic from drinking water.

[0011] In addition to the above mentioned advantages, because PPSU does not contain either of Bisphenol A (BPA) and Bisphenol S, PPSU is considered more endocrine safe. Indeed, particular care is required in the polymer-based selection for end uses involving food & beverage and blood contact. Recently, there is some regulatory pressure pushing the ban of PSU use in food and beverage applications because of BPA leaching. In contrast, recent research asserts that no concerns exist regarding migration of polymer-related substances from PPSU. See for example Polyphenylsulfone (PPSU) for baby bottles: a comprehensive assessment on polymer-related non-intentionally added substances (NIAS), Food Additives & Contaminants: Part A, vol. 35 (2018) 1421.

[0012] However, despite all of these promising studies, no examples of real application of membranes based on PPSU in industry have been found, such absence very likely associated with its limited solubility [Materials vol. 14 (2021) 5740] in common solvents : N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF) typically used in membrane manufacturing, the low flux and the high fouling of the obtained materials. Indeed DMF is frequently used in reverse osmosis membrane production, while DMAc is frequently used in hemodialysis membrane production. Clearly the poor solubility of PPSU in DMF and DMAc has hindered the development of large-scale production of commercial membranes based on PPSU for hemodialysis and water filtration end uses.

[0013] According to the article of Volkov et al. [Development of high flux ultrafiltration polyphenylsulfone membranes applying the systems with upper and lower critical solution temperatures: Effect of polyethylene glycol molecular weight and coagulation bath temperature. Journal of Membrane Science vol. 565 (2018) 266-280], the solvent choice for PPSU can be sorted as follows: N-methylpyrrolidone (NMP)> DMAc>DMF. This finding is in good agreement with similar results obtained by other- 3 - SSPU 2024 / 046research teams. Because PPSU solubility in DMF is less than 15wt%, the increase in polymer concentration in a DMF solution leads to gel formation. For this reason, NMP is mainly chosen as a solvent for PPSU.

[0014] All of these disadvantages, up to now, make PPSU unsuitable in terms of processability for membrane applications, in particular for hemodialysis and water filtration applications.

[0015] Membranes made from PAES are hydrophobic in nature and therefore endowed of water repellency, low water permeability. These membranes suffer from poor hydrophilicity that negatively affects water permeation performance. Hydrophobicity impedes water to penetrate into the polymeric membrane and therefore water permeability requires higher pressure and consumes more energy. Another relevant issue is the fouling phenomenon. The intrinsic hydrophobicity of PAES polymers also makes PAES-based membranes prone to fouling which negatively impacts their performance. Fouling is frequently the bottleneck of membrane processes, resulting in a sharp decline in permeate flux and decrement in membrane lifetime. Fouling is caused by hydrophobic interactions and electrostatic forces between membrane materials and foulants (e.g., microorganisms, proteins, or organic matter) originating from a fluid to be treated though the membrane. In particular, fouling is initiated by the adsorption of foulants onto the membrane surface and the interior structure, resulting in pore blocking, cake layer formation, or biofilm formation. Fouling reduces temporarily or permanently the flux of permeation of water through the membrane, e.g., in ultrafiltration or microfiltration processes. Membrane fouling not only decreases membrane permeability and overall lifetime, but also increases maintenance costs due to extensive and frequent cleaning to remove foulants.

[0016] Forthat reason, PAES-based membranes are frequently modified to increase their hydrophilicity and reduce their fouling propensity before practical use. Enhancing surface hydrophilicity can be achieved by increasing the density of the hydrophilic groups at the membrane surface. By making inner surfaces of the inner pores hydrophilic, the capability of permeating water through porous PAES membrane is generally improved. Besides, it is generally accepted that an increase of the hydrophilicity of PAES membranes offers better fouling resistance because proteins and other foulants are hydrophobic in nature.

[0017] In order to overcome the mentioned disadvantages, several research studies have focused on effort to increasing hydrophilicity that affects the PPSU compatibility with solvent, PPSU compatibility additive and PPSU membrane performance (reduced fouling, increased PWP, chemical resistance to oxidant) - see for example, Membranes vol. 12 (2022) 247.- 4 - SSPU 2024 / 046

[0018] Several strategies can be employed to make a porous PPSU membrane more hydrophilic and thus rendering such membrane highly water permeable and highly resistant to fouling.

[0019] To target water treatment membranes, US 2013 / 0203873A1 (Kumar et al.) described hollow fiber membranes preparation by incorporating hydrophilic additives. The most versatile hydrophilic additives for the hollow fiber ultrafiltration membrane were found out to be cellulose derivatives, preferably cellulose acetate and cellulose acetate phthalate, which are rich in groups of carboxyl, hydroxyl and amine. The enhanced antifouling characteristics to nano particle of aluminum oxide was obtained by the modified PPSU hollow fiber membranes as compared to neat membranes.

[0020] Gronwald et al. (Separation and Purification Technology vol. 250 (2020) 117107) described membranes with Pluronic® F127 based multiblock copolymer additive M2 and Lutensol® AT80 based triblock copolymer additive T2 both coupled with hydrophobic PPSU building blocks (M = 7500 g mol-1) showed significantly elevated pure water permeance (PWP) and higher hydrophilicity (lower contact angle) compared to pristine PPSU membranes.

[0021] To target membrane preparation for ultrafiltration (UF), reverse osmosis (RO) and nanofiltration (NF), US2013 / 0203873A1 (by Linder et al.) described modified PPSU base polymers with one or more ionic groups (sulfonated, nitrated, ammonium, etc). According to the presented data, the resulting membranes are much more chemically resistant than commercial membranes and other membranes, such as, for example, membranes made from a combination of sulfonated polyphenylsulfone (SPPS) and aminated sulfonated polyphenylsulfone (SPPSNH2 ), where the flux and / or rejection drops rapidly upon exposure to the same sodium hypochlorite (NaOCI) solutions.

[0022] Bio-based polymers, which are prepared from renewable resources, are of interest to many industries. Developing naturally derived polymers capable of producing membranes is also of significant interest in the membrane-production field due to their environmental friendliness compared to petrochemical-based polymer membranes.

[0023] Isosorbide, a natural plant-based monomer, is a 100% bio-derived material produced by hydrogenating glucose to sorbitol followed by dehydration. Isosorbide is known to enhance thermal and optical properties when used in polymer compounds. It has been used to synthesize isosorbide-based polymers, such as polycarbonates, polyesters, and polyurethanes, and can be used in biomedical, coatings, and electronic-materials applications. See for example Novel bio-based polymer membranes fabricated from isosorbide incorporated poly(arylene ether)s for water treatment. European Polymer Journal vol. 136 (2020) 109931.- 5 - SSPU 2024 / 046

[0024] Other research teams have prepare isosorbide-PES membranes that exhibit a higher hydrophilicity, lower flux decline ratios than PES membrane at the pHs . Furthermore, the flux recovery ratios of the bio-based membrane in cross-flow filtration experiments of a protein solution at pH 4 were about 16% and 17% higher than that of PES, respectively. Ultrafiltration experiments with BSA revealed that the isosorbide PES membranes are advantageous in terms of membrane fouling due to their high hydrophilicities; hence, they are possible replacements for PES membranes derived from petrochemicals. See for example Ryu etal., Isosorbide-based Poly(arylene ether) biopolymer membranes for gas separation. Journal of Membrane Science vol. 706 (2024) 122928; Kim etal., Novel bio-based polymer membranes fabricated from isosorbide incorporated poly(arylene ether)s for water treatment. European Polymer Journal vol. 136 (2020) 109931.

[0025] The recent research article by Ryu et al. (Isosorbide-based Poly(arylene ether) biopolymer membranes for gas separation. Journal of Membrane Science vol. 706 (2024) 122928) replaced the BPA of PSU with isosorbide. The resulting polymer was used to prepare membrane for gas separation. The authors demonstrated the usage of biomass-derived Isosorbide-based poly(arylene ether)s for gas separation membranes as an alternative to petroleum-derived polymers. The substitution of BPA with isosorbide unit allows to enhances chain packing and achieve higher selectivity compared to the pristine PSU.

[0026] US2017 / 240708A1 relates to a polysulfone copolymer with excellent heat resistance and chemical resistance compared with existing polysulfone copolymers, and a method for preparing the same, wherein the polysulfone copolymer comprises, as repeat units, a sulfone-based compound, and an anhydrosugar alcohol, which is a biogenic material. Example 10 provides an example of a copolymer made from biphenol (80mol%), isosorbide (20 mol%) and dichlorodiphenylsulfone, which is said to be insoluble in DMAc (Table 5); however no porous membrane was made.

[0027] US2022 / 056216A1 relates to a polyarylene ether sulfone copolymer comprising in polymerized form: A) isosorbide, isomannide, isoidide or a mixture thereof (component A), B) at least one at least one nonsulfonated dihalodiary I sulfone (component B), and C) at least one sulfonated dihalodiaryl sulfone (component C), a process for its preparation and its use in the preparation of coatings, films, fibers, foams, membranes or molded articles. However no porous film, fiber, or membrane were made from a copolymer made from polymerization of component A) such as isosorbide, nonsulfonated dihalodiaryl sulfone, and biphenol.

[0028] SUMMARY

[0029] The various aspects of the present invention are set out in the appended set ofclaims.- 6 - SSPU 2024 / 046

[0030] A first aspect of the invention relates to a porous membrane comprising an aromatic biphenol-co-dianhydrohexitol sulfone copolymer (P1).

[0031] A second aspect of the invention relates to a polymeric composition which comprises an aromatic biphenol-co-dianhydrohexitol sulfone copolymer (P1) and a PSSU polymer (P2).

[0032] A third aspect of the invention relates to a method for improving the solubility and compatibility of a PSSU polymer (P2) in a polymeric dope solution, particularly comprising dimethylformamide (DMF) or dimethylacetamide (DMAc) or dimethyl isosorbide (DMI).

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 represents ternary polymer / water / NMP phase diagrams with biphenol-co- dianhydrohexitol sulfone copolymers (P1) according to the invention in comparison with commercial PPSU, PSU, and PES.

[0035] FIG. 2 and 3 represent SEM cross-section images with magnifications of 400x (a) and 5000x (b) of porous membranes E2 and E3 according to the invention.

[0036] FIG. 4 and 5 represent SEM cross-section images with magnifications of 400x (a) and 5000x (b) of comparative porous membranes CE4 (made from PSU) and CE5 (made from PES).

[0037] FIG. 6 and 7 represent SEM cross-section images with magnifications of 400x (a) and 5000x (b) of porous membranes E6 and E7 according to the invention.

[0038] FIG. 8 and 9 represent SEM cross-section images with magnifications of 400x (a) and 5000x (b) of comparative porous membranes CE10 (made from PSU) and CE11 (made from PES).

[0039] FIG. 10 represents a SEM cross-section image with a magnification of 400x of porous membrane E8 according to the invention.

[0040] FIG. 11 and 12 represent SEM cross-section images with a magnification of 600x of porous membranes E12 and E13 according to the invention.

[0041] FIG. 13 represents a SEM cross-section image with a magnification of 600x of comparative membrane CE14 (made from PSU).

[0042] FIG. 14 represents SEM cross-section images with magnifications of 60x (a), 500x (b) and 2000x (c) of comparative hollow fiber CE15b (made from PES).

[0043] FIG. 15, 16 and 17 represent SEM cross-section images with magnifications of 60x (a), 500x (b) and 2000x (c) of hollow fibers E16b, E17b, E18b, according to the invention.

[0044] FIG. 18 and 19 represent SEM cross-section images with magnifications of 800x (a) and 2000x (b1 & b2) of comparative films CE19 and CE20 which are casted from copolymer (P1) solutions in DMAc according to the method described in US 2017 / 240708A1.

[0045] DETAILED DESCRIPTION- 7 - SSPU 2024 / 046

[0046] In the present application:- any description, even though described in relation to a specific embodiment, is applicable to and interchangeable with other embodiments of the present disclosure; - where an element or component is said to be included in and / or selected from a list of recited elements or components, it should be understood that in related embodiments explicitly contemplated here, the element or component can also be any one of the individual recited elements or components, or can also be selected from a group consisting of any two or more of the explicitly listed elements or components; any element or component recited in a list of elements or components may be omitted from such list; and- any recitation herein of numerical ranges by endpoints includes all numbers subsumed within the recited ranges as well as the endpoints of the range and equivalents.

[0047] The indeterminate article "a" in expressions like "a monomer" etc... is intended to mean "one or more", or "at least one" unless indicated otherwise.

[0048] The use of brackets "( )" before and after names, symbols or numbers identifying formulae or parts of formulae, e.g., polymer (P1), recurring unit (RPI), etc..., has the mere purpose of better distinguishing that name, symbol or number from the rest of the text; thus, said parentheses could also be omitted.

[0049] The term "method" is to be regarded as a synonym of "process" and vice versa.

[0050] As used herein, the term “diol” refers to a monomer comprising two hydroxyl groups.

[0051] As used herein, the terms “dihalogenated monomer”, “dihalo monomer” or“di halodiaryl sulfone compound” refer to a compound comprising two halogen groups.

[0052] As used herein, the term “total wt% monomers” is defined as the weight of the monomers based on the total weights of monomers and solvent initially present during condensation (in the reaction medium).

[0053] In the present disclosure, the term “recurring unit” designates the smallest unit of a polymer which is repeating in the main chain and which is composed of a condensation of a diol monomer and a dihalodiary I sulfone monomer. The term “recurring unit” is synonymous to the terms “repeating unit” and “structural unit”.

[0054] As used herein, the term “copolymer” encompasses a polymer which may have two or more different types of recurring units. The copolymer (P1) may be obtained from polycondensation of at least two diol monomers and at least one dihalodiaryl sulfone monomer, or from polycondensation of at least two diol monomers, at least one dihalodiaryl sulfone monomer and at least one other dihalogenated monomer. The term “homopolymer” encompasses a polymer which only has one type of recurring unit. Meaning, a homopolymer is obtained from the condensation of only one diol monomer and only one dihalodiaryl monomer.- 8 - SSPU 2024 / 046

[0055] Porous membrane

[0056] An aspect of the present invention is a porous membrane having- a gravimetric porosity of at least 75%, or more than 75%, or at least 76%, or at least 77%, or at least 78%, and- a pure water permeance (PWP) of at least 75 L / m2 / h / bar [“LMHB”], or more than 75 LMHB, or at least 76 LMHB, or at least 77 LMHB, or at least 78 LMHB, or at least 79 LMHB, or at least 80 LMHB, or at least 81 LMHB, or at least 82 LMHB, or at least 83 LMHB.

[0057] The porous membrane according to the present invention has a gravimetric porosity of at most 95 %, or at most 94 %, or at most 93 %, or at most 92 %, or at most 91 %, or at most 90 %.

[0058] The porous membrane of the present invention preferably has a gravimetric porosity of from 75% and up to 95 %, more preferably from more than 75% and up to 95 %, still more preferably from 76% and up to 94 %, yet more preferably from 77% and up to 94 %, even more preferably from 78% and up to 93 %.

[0059] As used herein, the “gravimetric porosity” of the porous membrane is defined as the volume of the pores divided by the total volume of the membrane. The gravimetric porosity is preferably measured using the method described in the Examples.

[0060] The porous membrane according to the present invention may have a PWP of at most 500 LMHB, or at most 475 LMHB, or at most 450 LMHB.

[0061] The porous membrane of the present invention preferably has a pure water permeance (PWP) of from 75 LMHB and up to 500 LMHB, more preferably from more than 75 LMHB and up to 475 LMHB.

[0062] As used herein, the “pure water permeance” (PWP) in L / m2 / h / bar is provided by the water flux (J in L / m2 / h) through a membrane divided by transmembrane pressure (bar).

[0063] Water flux (J) through a membrane at given transmembrane pressure, is defined as the volume which permeates per unit area and per unit time. The flux is calculated with the following equation [1]:VJ =A fltEquation [1],wherein:- V (in L) is the volume of permeate,- A (in m2) is the membrane area, and- At (in h) is the operation time.

[0064] Particular suitable methods for measuring the water flux (J) and pure water permeance (PWP) for flat membranes and hollow fibers are provided in theExamples.- 9 - SSPU 2024 / 046

[0065] Copolymer (P1)

[0066] The porous membrane comprises at least one aromatic sulfone copolymer (P1)[hereinafter “copolymer (P1 )”] .

[0067] The copolymer (P1) in the porous membrane according to the invention comprises collectively at least 50 mol.%, at least 60 mol.%, at least 70 mol.%, at least 75 mol.%, at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 97 mol.%, at least 98 mol.%, or at least 99 mol.%, of recurring units (RPI) and recurring units (R*PI), said mol.% being based on the total molar amount of recurring units in the copolymer (P1). The term “collectively” means the combined amounts of recurring units (RPI) and (R*PI).

[0068] Preferably, substantially all of the recurring units in the copolymer (P1) are recurring units (RPI) and (R*PI). The expression “substantially all” in relation to the recurring units of the copolymer (P1) ) means at least 99 mol.% based on the total molar amount of recurring units of the copolymer (P1) and is hereby intended to mean that minor amounts, generally below 1 % moles, preferably below 0.5 % moles, of other recurring units may be tolerated, e.g. as a result of lower purity in monomers used.

[0069] The molar ratio of the recurring unit (R*PI) to the recurring unit (RPI) in the copolymer (P1) may be from 5 / 95 to 80 / 20, preferably from 10 / 90 to 70 / 30, more preferably from 10 / 90 to 65 / 35, yet more preferably from 10 / 90 to 60 / 40, still more preferably from 10 / 90 to 50 / 50, even more preferably from 10 / 90 to 40 / 60, or from 10 / 90 to 35 / 65, most preferably from 10 / 90 to 30 / 70.

[0070] The copolymer (P1) may comprise at least 5 mol.%, or at least 8 mol.%, or at least 10 mol.%, or at least 12 mol.%, or at least 15 mol.%, of the recurring unit (R*PI), based on the total molar amount of recurring units in the copolymer (P1), and at most 50 mol. %, or at most 45 mol.%, or at most 40 mol.%, or at most 35 mol.%, or less than 35 mol.%, or at most 30 mol.%, of the recurring unit (R*PI), based on the total molar amount of recurring units in the copolymer (P1). Preferably, the copolymer (P1) comprises at least 10 mol.%, or at least 12 mol.%, or at least 15 mol.%, and less than 35 mol.%, or at most 30 mol.%, based on the total molar amount of recurring units in the copolymer (P1).

[0071] The copolymer (P1) may comprise at least 35 mol.%, or at least 40 mol.%, or at least 45 mol.%, or at least 50 mol.%, or at least 55 mol.%, or at least 60 mol.%, or at least 65 mol.%, or more than 65 mol.%, or at least 70 mol.%, of the recurring unit (RPI), and at most 95 mol. %, or at most 93 mol.%, or at most 90 mol.%, of the recurring unit (RPI), the mol.% being based on the total molar amount of recurring units in the copolymer (P1). Preferably, the copolymer (P1) comprises from more than 65 mol.% to 90 mol.%, or from 70 mol.% to 90 mol.%, or from 70 mol.% to 88 mol.%, of the- 10 - SSPU 2024 / 046recurring unit (RPI), the mol.% being based on the total molar amount of recurring units in the copolymer (P1).

[0073] The recurring unit (RPI) in the copolymer (P1) is represented by formula (M1):

[0074] The recurring unit (R*PI) in the copolymer (P1) may be represented by any formula selected from following formulae (N1), (N2), (N3), and / or (N4):wherein each Q’, being the same or different in formula (N4), is an acyclic moiety.

[0075] The acyclic moiety Q’ in formula (N4) may be derived from an acyclic diol selected from alkylene oxides and / or poly(alkylene oxide)s, preferably selected from the group consisting of ethylene glycol; propylene glycol [HO-CH2-CH(CH3)-OH]; 1 ,3-- 11 - SSPU 2024 / 046propanediol; 1 ,4-butanediol; 1 ,5-pentanediol; 1 ,6-hexanediol; 1 ,8-octanediol; 1 ,10- decanediol; 2-methyl-1 ,3-propanediol; 2,2-dimethylpropane-1 ,3-diol; 2,2,4-trimethyl- 1 ,3-pentanediol; 2-ethy l-2-buty 1-1 ,3-propanediol; polyethylene glycol); polypropylene glycol); poly(tetramethylene oxide); and any combination of two or more thereof.

[0076] Q’ in formula (N4) may be represented by formula (VI): -[Rk-O-]z-Rk-,in which Rk is selected from alkylenes, preferably alkylenes having from 1 to 10 carbon atoms, more preferably selected from the group consisting of methylene [CH2], ethylene [CH2-CH2], isopropylene [CH2-CH(CH3)], tetramethylene [CH2-CH2- CH2-CH2], 2,2-dimethylpropylene [CH2-C(CH3)2-CH2], 2-ethyl-2-butyl-1,3-propylene [CH2-C(C2H5)(C4H9)-CH2], 2,2,4-trimethyl-1 ,3-pentylene [CH(C(CH3)2)-C(CH3)2-CH2], and any combination thereof; and z is 0 or an integer from 1 to 500, preferably an integer from 2 to 200, more preferably an integer from 2 to 100, yet more preferably an integer from 2 to 50;preferably, represented by any one of following formulae (VI’), (VI”), (VI’”) and (VI””): -[CH2-CH2-O]Z-CH2-CH2- (VI’),-[CH2-CH(CH3)-O]Z-CH2-CH(CH3)- (VI”),-[CH2-CH2-CH2-CH2-O]Z-CH2-CH2-CH2-CH2- (VI’”),-[CH2-C(CH3)2-CH2-O]Z-CH2-C(CH3)2-CH2- (VI””),in which z is 0 or an integer from 1 to 500, preferably an integer from 2 to 200, more preferably an integer from 2 to 100, yet more preferably an integer from 2 to 50.

[0077] The recurring unit (R*PI) in the copolymer (P1) is preferably represented by formula (N1).

[0078] The copolymer (P1) preferably comprises at least 5 mol.%, or at least 8 mol.%, or at least 10 mol.%, or at least 12 mol.%, or at least 15 mol.%, of the recurring units (R*PI) of formula (N1), based on the total molar amount of recurring units in the copolymer (P1), and at most 50 mol. %, or at most 45 mol.%, or at most 40 mol. %, or at most 35 mol. %, or less than 35 mol.%, or at most 30 mol. %, of the recurring units (R*PI) of formula (N1), based on the total molar amount of recurring units in the copolymer (P1).

[0079] The copolymer (P1) preferably comprises at least 35 mol.%, or at least 40 mol.%, or at least 45 mol.%, or at least 50 mol.%, or at least 55 mol.%, or at least 60 mol.%, or at least 65 mol.%, or more than 65 mol.%, or at least 70 mol.%, of the recurring unit (RPI) of formula (M1), and at most 95 mol. %, or at most 93 mol.%, or at most 90 mol.%, of the recurring unit (RPI) of formula (M1), the mol.% being based on the total molar amount of recurring units in the copolymer (P1). More preferably, the copolymer (P1) comprises from more than 65 mol.% to 90 mol.%, or from 70 mol.% to 90 mol.%, or from 70 mol.% to 88 mol.%, of the recurring unit (RPI) of formula- 12 - SSPU 2024 / 046(M1), the mol.% being based on the total molar amount of recurring units in the copolymer (P1).

[0080] Optional recurring units (Rpi’j and (R*PI’)

[0081] Alternatively, the copolymer (P1) may further comprise at least one additional recurring unit different than the recurring units (R*pT) and (Rpi’).

[0082] Particularly, the copolymer (P1) may further comprise, collectively, at least 5 mol.% of sulfone recurring units (RPI’) and sulfone recurring units (R*PI’).

[0083] The sulfone recurring unit (RPI ) is represented by formula (MT):(MT),wherein in formulae (MT):each R is selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate; andeach i is an integer from 0 to 4, with the proviso that at least one i is not zero, preferably each i is 1.

[0084] The sulfone recurring unit (R*PI’) may be represented by any formula selected from- 13 - SSPU 2024 / 046(N4)_ wherein in formulas (N1 ’), (N2’), (N3’), (N4’):- each R is selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (- SO3H), and alkyl sulfonate; and- each i is an integer from 0 to 4, with the proviso that at least one i is not zero, preferably each i is 1 ; andwherein Q’ is formula (N4’) is the same as previously described for formula (N4).

[0085] For any one of the formulae (MT), (N1 ’), (N2’), (N’3) and (N4’), when at least one i is 1 , then its corresponding R is preferably selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (- SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, and alkyl phosphonate, more preferably selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, and alkyl phosphonate.

[0086] The molar ratio of the recurring units (R*PI’) to the recurring units (RPI’) in the copolymer (P1) may be from 5 / 95 to 50 / 50, preferably from 10 / 90 to 45 / 55, more preferably from 10 / 90 to 40 / 60, yet more preferably from 10 / 90 to 35 / 65, still more preferably from 12 / 88 to 35 / 65, even more preferably from 12 / 88 to 30 / 70, most preferably from 15 / 85 to 30 / 70.

[0087] Particularly, when the copolymer (P1) comprises sulfone recurring units (RPI), (R*PI), (Rp ) and (R*PI’)> substantially all recurring units of said copolymer (P1) (meaning at- 14 - SSPU 2024 / 046least 99 mol.% based on the total molar amount of recurring units of said copolymer (P1)) may be :- sulfone recurring units (RPI) represented by formula (M1), sulfone recurring units (RPI’) represented by formula (MT), sulfone recurring units (R*PI) represented by formula (N1), and sulfone recurring units (R*PI’) represented by formula (N1 ’); or - sulfone recurring units (RPI) represented by formula (M1), sulfone recurring units (Rp ) represented by formula (MT), sulfone recurring units (R*PI) represented by formula (N2), and sulfone recurring units (R*PI’) represented by formula (N2’); or - sulfone recurring units (RPI) represented by formula (M1), sulfone recurring units (Rp ) represented by formula (MT), sulfone recurring units (R*PI) represented by formula (N3), and sulfone recurring units (R*PI’) represented by formula (N3’); wherein, in formulas (MT), (N1 ’), (N2’) and (N3’), each i is 1 and their corresponding R is the same and selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate.

[0088] Preferably, when the copolymer (P1) comprises sulfone recurring units (RPI), (R*PI), (RP ) and (R*pT), substantially all recurring units of said copolymer (P1) (meaning at least 99 mol.% based on the total molar amount of recurring units of said copolymer (P1)) are sulfone recurring units (RPI) represented by formula (M1), sulfone recurring units (Rp ) represented by formula (MT), sulfone recurring units (R*PI) represented by formula (N1), and sulfone recurring units (R*PI’) represented by formula (N1 ’), wherein in formulas (MT) and (N1 ’), each i is 1 and their corresponding R is the same and selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate.

[0089] The copolymer (P1) may have a glass transition temperature (Tg) ranging from 180°C to 250°C, preferably from 190 to 240°C, more preferably from 200°C to 235°C, more preferably from 220°C to 230°C, as measured by differential scanning calorimetry (DSC) using the second heat curve. The Tg may be measured according to ASTM D3418 or particularly according to the DSC method described in the examples.

[0090] PAES polymer (P2)

[0091] The porous membrane may further comprise at least one aromatic sulfone polymer (P2) [hereinafter “ PAES polymer (P2)”] different than the copolymer (P1).

[0092] When the porous membrane comprises at least one copolymer (P1) and at least one PAES polymer (P2), the amount of the copolymer (P1) may be from 20 parts by weight [“pbw”] to 90 pbw, preferably from 25 pbw to 80 pbw, more preferably from 30 pbw to 70 pbw, yet more preferably from 35 pbw to 65 pbw, even more preferably from 40 pbw to 60 pbw, most preferably 50 pbw, said pbw being based on 100 parts of the combination of the copolymer (P1) and the PAES polymer (P2).- 15 - SSPU 2024 / 046

[0093] The PAES polymer (P2) comprises at least 80 mol.%, or at least 85 mol.%, or at least 90 mol.%, or at least 95 mol.%, or at least 98 mol.%, or at least 99 mol.%, of recurring units (RP2) represented by formulae (M2) or a combination of formulae (M2) and (M2’), based on the total molar amount of recurring units in the PAES polymer (P2).

[0094] Recurring unit (RPZ)

[0095] The recurring unit (RP2) is represented by formula (M2) or a combination of formulaeT is selected from the group consisting of a single bond, -SO2-, -C(CH3)2- and any mixture therefrom, preferably selected from a single bond and / or -SO2-, more preferably being a single bond;each R’ is independently selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate; andeach k is independently an integer from 0 to 4, with the proviso that at least one k is not zero, preferably each k is 1.

[0096] The recurring unit (RP2) is preferably represented by formula (M2).

[0097] The recurring unit (RP2) in the PAES polymer (P2) is more preferably according to any of the following formulas (M1), (M2b) or (M2c):- 16 - SSPU 2024 / 046).

[0098] The recurring unit (RP2) is yet more preferably represented by formula (M1) which is the same as formula (M2) in which T is a single bond.

[0099] The recurring unit (RP2) is most preferably the same as the recurring unit (RPI) described previously in relation to the copolymer (P1).

[0100] As used herein, a polyphenylsulfone (PPSU) polymer (P2) denotes any polymer comprising at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 98 mol.%, or at least 99 mol.%, of recurring units (RPPSU) of formula (M1),the mol. % being based on the total number of moles of recurring units in the PPSU polymer. Formula (M1) is the same as formula (M2) in which T is a single bond. PPSU can be prepared by known methods and is notably available as RADEL® PPSU from Syensqo Specialty Polymers USA, L.L.C.

[0101] As used herein, a polyethersulfone (PES) polymer (P2) denotes any polymer comprising at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, or at least 99 mol. % of recurring units (RPES) of the formula (M2b),the mol. % being based on the total number of moles of recurring units in the PES polymer. Formula (M2b) is the same as formula (M2) in which T is -SO2-. PES can be prepared by known methods and is notably available as VERADEL® PES from Syensqo Specialty Polymers USA, L.L.C.

[0102] As used herein, a polysulfone (PSU) polymer (P2) denotes any polymer comprising at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, or at least 99 mol. % of recurring units (Rpsu) of the formula (M2c),- 17 - SSPU 2024 / 046the mol. % being based on the total number of moles of recurring units in the PSU polymer. Formula (M2c) is the same as formula (M2) in which T isC(CH3)2-. PSU can be prepared by known methods and is notably available as Udel® PSU from Syensqo Specialty Polymers USA, L.L.C.

[0103] As used herein, a sulfonated polyphenylsulfone (sPPSU) polymer (P2) comprises at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, or at least 98 mol. % of, or consists essentially of, a combination of recurring units (Rppsu) of formula (M1) and recurring units (RSPPSU) of the formula (M2’), the mol. % being based on the total number of moles of recurring units in the sPPSU polymer, wherein in the formula (M2’), T is a single bond; each R’ is independently selected from the group consisting of alkali metal phosphonate, alkaline earth metal sulfonate, sulfonic acid, and alkyl sulfonate; and each k is independently an integer of 1 to 4, preferably equals to 1.

[0104] As used herein, a sulfonated polyethersulfone (sPES) polymer (P2) comprises at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, or at least 98 mol. % of, or consists essentially of, a combination of recurring units (RPES) of the formula (M2b) and recurring units (RSPES) of the formula (M2’), the mol. % being based on the total number of moles of recurring units in the sPES polymer, wherein in the formula (M2’), T= -SO2- ; each R’ is independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid, and alkyl sulfonate; and each k is independently an integer of 1 to 4, preferably equals to 1.

[0105] As used herein, a sulfonated polysulfone (sPSU) polymer (P2) comprises at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, or at least 98 mol. % of, or consists essentially of, a combination of recurring units (RPSU) of the formula (M2c) and recurring units (RSPSU) of the formula (M2’), the mol. % being based on the total number of moles of recurring units in the sPSU polymer, wherein in the formula (M2’), T= -C(CH3)2- ; each R’ is independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid, and alkyl sulfonate; and each k is independently an integer of 1 to 4, preferably equals to 1.

[0106] The PAES polymer (P2) preferably comprises at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 98 mol.%, or at least 99 mol.%, of the- 18 - SSPU 2024 / 046recurring unit (RP2) represented by formula selected from formula (M1) and / or formula (M2b), based on the total molar amount of recurring units in the PAES polymer (P2).

[0107] The PAES polymer (P2) is yet more preferably a PPSU polymer (P2) or a PES polymer (P2).

[0108] The PAES polymer (P2) is most preferably a PPSU polymer (P2).

[0109] The PAES polymer (P2) in the polymeric composition of the present invention has a Tg ranging from 120 and 250°C, preferably from 170 and 240°C, more preferably from 180 and 225°C, as measured by differential scanning calorimetry (DSC) according to ASTM D3418 using the second heat curve.

[0110] When the PAES polymer (P2) is PPSU or PSU, such PPSU or PSU polymer (P2) is more hydrophobic than the copolymer (P1).

[0111] When the PAES polymer (P2) is PES, such PES polymer (P2) is more hydrophilic than the copolymer (P1).

[0112] The hydrophilicity of the copolymer (P1) can be compared to that of the PAES polymer (P2) by the use of ternary phase diagrams. A ternary phase diagram shows the water tolerance of polymer in a certain solvent and temperature. The diagram is widely used to compare / understand the cloudy point, the precipitation propensity and the hydrophilicity character, see for example Applied Polymer Science vol. 65 (1997) p.2643, and Journal of Membrane Science vol. 59 (1991) p. 219. Such use of ternary phase diagrams is illustrated in Example 6 and FIG. 1 in the present application.

[0113] When the PAES polymer (P2) is PPSU or PSU, the copolymer (P1) may be used as a polymeric additive in a polymeric dope solution to the more hydrophobic PAES polymer (P2) in order to improve the wettability, water uptake, water flux rate of the porous membrane including such combination of copolymer (P1) and the more hydrophobic PAES polymer (P2), compared to a membrane including the more hydrophobic PAES polymer (P2) but excluding the copolymer (P1).

[0114] Pore former (A)

[0115] The porous membrane may further comprise at least one pore former (A).

[0116] The at least one pore former (A) may be selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”];at least one polyvinyl alcohol;at least one polyvinyl acetate;cellulose acetate; andany combination thereof.- 19 - SSPU 2024 / 046

[0117] The at least one pore former (A) in the porous membrane may include a polyvinylpyrrolidones [“PVP”]. The PVP preferably has a molecular weight of at least 5,000 g / mol and up to 360,000 g / mol.

[0118] When the porous membrane comprises at least one copolymer (P1) and does not contain a PAES polymer (P2), the amount of the PVP as pore former (A) may be from 5 to 30 parts by weight [“pbw”], preferably from 5 to 25 pbw, said pbw being based on 100 parts of the copolymer (P1).

[0119] When the porous membrane comprises at least one copolymer (P1) and at least one PAES polymer (P2), the amount of the PVP as pore former (A) may be from 5 to 30 parts by weight [“pbw”], preferably from 5 to 25 pbw, said pbw being based on 100 parts of the combination of the copolymer (P1) and the PAES polymer (P2).

[0120] The at least one pore former (A) in the porous membrane may include at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably a polyethylene glycol [“PEG”] having a formula weight of from 200 g / mol to 900 g / mol.

[0121] When the porous membrane comprises at least one copolymer (P1) and does not contain a PAES polymer (P2), the amount of the PEG as pore former (A) may be from 5 to 30 parts by weight [“pbw”], preferably from 5 to 25 pbw, said pbw being based on 100 parts of the copolymer (P1).

[0122] When the porous membrane comprises at least one copolymer (P1) and at least one PAES polymer (P2), the amount of the PEG as pore former (A) may be from 5 to 30 parts by weight [“pbw”], preferably from 5 to 25 pbw, said pbw being based on 100 parts by weight of the combination of the copolymer (P1) and the PAES polymer (P2).

[0123] The at least one pore former (A) in the porous membrane may include a pore former (A*) selected from:at least one (poly) hydroxy I aliphatic alcohol having from 1 to 6 carbon atoms, preferably at least one glycerol compound,at least one carboxylic acid comprising at least 3 carbon atoms, preferably propionic acid;at least one polyvinyl alcohol;at least one polyvinyl acetate; and / orcellulose acetate.

[0124] The porous membrane preferably excludes at least one of the pore formers (A*) provided hereinabove.

[0125] Optional additional polymer(s)

[0126] The porous membrane of the present invention preferably excludes polymers other than the copolymer (P1), PAES polymer (P2) and polymers used as pore formers (A), such as PVP, PEG. This may be particular desirable when the intended use of the- 20 - SSPU 2024 / 046porous membrane is for water treatment, water purification and / or hemodialysis enduse.

[0127] Alternatively, the porous membrane of the present invention may include an additional polymer that is different than the copolymer (P1), PAES polymer (P2) and polymers used as pore formers (A), such as PVP, PEG.

[0128] In particular, when the intended use of the porous membrane is for reverse osmosis [“RO”] such as in desalination application, the porous membrane may further include an additional polymer selected from polyamides and / or polyesters, preferably a crosslinked polyamide [hereinafter “xPA”] and / or a poly(ethylene naphthalate) [hereinafter “PET”]. In such instance, these additional polymer(s) generally form different polymeric layers in the final RO membrane which sandwich the porous membrane layer containing the copolymer (P1) according to the invention. For example, for a RO membrane having a thin-film composite structure, the porous membrane support layer (containing the sulfone copolymer (P1)) according to the invention is preferably casted on a PET nonwoven layer (substrate) and coagulated in a nonsolvent (preferably water). An interfacial polymerization is then carried out to create a thin selective layer of crosslinked polyamide on top of such a porous membrane layer.

[0129] As used herein, a polyethylene naphthalate) [“PET”] is formed by polycondensation of terephthalic acid and ethylene glycol.

[0130] As used herein, a crosslinked polyamide [“xPA”] denotes a polyamide selected from two main types of crosslinked polyamides used in commercial desalination membranes. The first type is a crosslinked polyamide (“MPD-TMC”) made from M- phenylenediamine (MPD) and trimesoyl chloride (TMC). This MPD-TMC polyamide is commonly used in the xPA layers of reverse osmosis (RO) membranes. The second type is a crosslinked polypiperazine amide (PIP-TMC) made from piperazine (PIP) and trimesoyl chloride (TMC); this PIP-TMC polyamide is typically used in the xPA layers of nanofiltration membranes.

[0131] Type of porous membrane

[0132] From an architectural perspective, the porous membrane of the present invention may be provided under the form of flat structure (e.g. a film, a sheet or any plurality thereof), corrugated structures (e.g., corrugated sheets), tubular structures (e.g. having a plurality of tubes), or hollow fibers.

[0133] The porous membrane of the present preferably includes a porous film or sheet, a hollow fiber or tube, or a porous support or selective layer which is part of a thin-film composite membrane.

[0134] The porous membrane may be symmetric or asymmetric.- 21 - SSPU 2024 / 046

[0135] As used herein, a “porous membrane” according to the present invention is a separating article that permeates at least one component while rejecting another component. The porous membrane may be partly porous, selectively permeable, such as a membrane which is pervious in one direction, or may be porous.

[0136] As used herein, a “membrane layer” according to the present invention is generally understood to be a polymeric layer adjacent to a substrate or adjacent to another polymeric layer (e.g., crosslinked polyamide selective layer) or sandwiched between another polymeric layer and a substrate. The substrate may be made from any suitable known material, such as crystalline or amorphous polymeric materials, preferably a polyester (e.g., PET) in a thin-film composite membrane.

[0137] Tubular porous membranes are classified based on their dimensions in tubular membranes having a diameter greater than 3 mm; capillary membranes, having a diameter comprised between 0.5 mm and 3 mm; and hollow fibers having an outer diameter of less than 1.5 mm. Capillary membranes are otherwise referred to as hollow fibers. Hollow fibers are particularly advantageous in applications where compact modules with high surface areas are required.

[0138] A hollow fiber may have at least one, preferably at least 2, more preferably at least 3, of the following characteristics: a wet thickness from 170 to 230 microns; an outer diameter from 1.05 mm to 1.5 mm, or from 1.1 mm to 1.4 mm; an internal diameter from 0.7 to 1.0 and / or a concentricity of from 70 to 99%, or from 72 to 97%, or from 75 to 95%. The wet thickness, outer diameter, internal diameter and concentricity of hollow fiber may be measured as described in the examples.

[0139] As used herein, a “fiber” according to the present invention is generally understood to be a flexible structure whose width is thin compared to its length. Fibers preferably have an average thickness of 20 to 500 microns, preferably of from 50 to 300 microns, more preferably 75 to 250 microns, still more preferably of from 100 to 240 microns, yet more preferably of from 150 to 225 microns.

[0140] The porous membrane of the present invention in form of film or sheet may have an average thickness of from about 25 microns (pm) to about 1 mm, preferably from about 50 pm to about 600 pm, more preferably from about 60 pm to about 400 pm, yet more preferably from about 70 pm to about 350 pm.

[0141] The porous membrane of the present invention in form of a porous support membrane layer may have an average thickness of from about 25 microns (pm) to about 300 pm,, preferably from about 30 pm to about 250 pm, more preferably from about 100 pm to about 200 pm. Such porous support layer may be part of a thin-film composite membrane.- 22 - SSPU 2024 / 046

[0142] When the porous membrane of the present invention is in form of a thin selective layer, its average thickness may be from about 0.1 microns (pm) to about 1 pm. Such a thin selective layer may be used for gas separation.

[0143] The thickness of the porous membrane whose ranges are provided hereinabove may be measured on a wet membrane or dry membrane.

[0144] Suitable methods for measuring the wet thickness of the porous membrane are provided in the Examples.

[0145] As per the pore size is concerned, full range of porous membranes, including for microfiltration, ultrafiltration, nanofiltration, ion-exchange, and reverse osmosis can be advantageously manufactured.

[0146] The porous membrane of the present invention may be a microporous membrane which can be characterized by its average pore diameter and porosity, i.e., the fraction of the total membrane that is porous.

[0147] The porous membrane of the present invention may comprise pores, wherein at least 90 % by volume of the said pores has an average pore diameter of less than 5 pm.

[0148] The porous membrane of the present invention may be a symmetric membrane, an asymmetric membrane, or a membrane part (such as a membrane layer).

[0149] As used herein, a symmetric membrane is a membrane having a uniform structure throughout its thickness.

[0150] As used herein, an asymmetric membrane is a membrane having pores which are not homogeneously distributed throughout its thickness. An asymmetric membrane may be characterized by a thin selective layer (e.g., 0.1-1 micron thick) and a highly porous thick layer (e.g., 100-200 micron thick) which acts as a support for the thin selective layer and has little effect on the separation characteristics of the membrane. As an example, the porous membrane according to the present invention may be a thin selective layer in an asymmetric membrane disposed on an underlying layer or substrate having a same composition or a different composition.

[0151] Alternatively, the porous membrane according to the present invention may be a porous support layer of a thin-film composite membrane, on top of which is disposed a thin selective layer having a different composition.

[0152] The porous membrane is preferably selected from- one or more hollow fibers, such as one or more asymmetric hollow fibers,- one or more flat membranes, such as one or more asymmetric flat membranes, or - a support or selective porous layer in a thin-film composite membrane.

[0153] The porous membrane may be used in various applications, preferably in hemodialysis, desalination and / or water filtration.- 23 - SSPU 2024 / 046

[0154] The porous membrane of the present invention is intended to come in contact with an aqueous solution, water, a biological fluid such as blood, plasma, or serum, or a food product such as fruit juice, milk, beer.

[0155] When the porous membrane of the present invention is a porous layer in a composite membrane, a person of ordinary skill in the art will know which layer is intended to contact a fluid like an aqueous medium, such as water, an aqueous solution (e.g., alkaline), a biological fluid (e.g., blood, plasma or serum) and / or food product (e.g., fruit juice, milk, beer) based upon the intended application. The porous layer may be an external or internal layer of the composite membrane. At least a portion of that layer may come into direct contact with the fluid in its intended application. For example, a medical membrane may have an external layer intended to come into direct contact with a biological fluid.

[0156] Reverse Osmosis Membrane

[0157] When the porous membrane of the present invention is intended for use in a reverse osmosis (RO) module such as for desalination application, the porous membrane is preferably a porous support membrane layer in a composite membrane which supports a thin selective layer (e.g., average thickness of from about 0.1 pm to about 1 pm).

[0158] Such porous support membrane layer is preferably made from the copolymer (P1) and optionally a pore former (A), preferably a PEG.

[0159] The dope solution for casting the porous membrane intended for RO use may omit any pore formers (A).

[0160] For such RO end-use, the porous membrane is preferably made (preferably casted) from a DMF polymeric dope solution.

[0161] Hence, the porous membrane of the present invention intended for use in reverse osmosis preferably comprises a porous support membrane layer formed from the copolymer (P1) which supports a thin selective layer, preferably a thin-film polyamide selective layer formed by interfacial polymerization on the support layer, the porous support membrane layer being casted from a dope solution comprising the copolymer (P1) in N,N-dimethylformamide (DMF) as solvent. Preferably, the copolymer (P1) comprises at least 10 mol.% to at most 30 mol.% of the recurring units (R*PI) of formula (N1), the mol% being based on the total molar amount of recurring units in the copolymer (P1).

[0162] Hemodialysis Membrane

[0163] When the porous membrane of the present invention is intended for use in a hemodialysis module, the porous membrane is a hollow fiber. Its average thickness may be from 0.5 to 500 microns, preferably from 50 to 300 microns, more preferably from 100 to 250 microns, still more preferably from 150 to 250 microns.- 24 - SSPU 2024 / 046

[0164] Such a hollow fiber porous membrane is preferably made from a dope solution comprising a combination of the copolymer (P1), optionally a PPSU polymer (P2) and a pore former (A), such as a PVP, a PEG or combination thereof, preferably a PVP, such as 3-6 wt% PVP in dope solution.

[0165] For such hemodialysis end-use, the porous membrane is preferably made from a DMAc or NMP polymeric dope solution.

[0166] Hence, the porous membrane of the present invention intended for use in hemodialysis is preferably a hollow fiber membrane comprising said copolymer (P1), wherein the hollow fiber has an average thickness from 0.5 to 500 microns and is produced by spinning a dope solution comprising the copolymer (P1), optionally a PPSU polymer (P2), 3 to 6 wt% of polyvinylpyrrolidone (PVP) of molecular weight 5,000-360,000 g / mol in dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), wherein the recurring unit of optional PPSU polymer (P2) is represented by the formula (M1). Preferably, the copolymer (P1) comprises at least 10 mol.% to at most 30 mol.% of the recurring units (R*PI) of formula (N1), the mol% being based on the total molar amount of recurring units in the copolymer (P1).

[0167] Water filtration membrane

[0168] When the porous membrane of the present invention is intended for use in a water filtration module, the porous membrane may be a porous flat sheet or hollow fiber.

[0169] The average thickness of the flat sheet may be from about 25 microns to about 1 mm, preferably from about 50 microns to about 600 microns, more preferably from about 60 microns to about 400 microns, yet more preferably from about 70 microns to about 350 microns.

[0170] The average wet thickness of the hollow fiber may be from 0.5 to 500 microns, preferably from 0.5 to 250 microns.

[0171] Such porous flat sheet or hollow fiber porous membrane intended for water filtration is preferably made from a polymeric dope solution comprising the copolymer (P1), optionally a PPSU polymer (P2) and a pore former (A), such as a PVP, a PEG or combination thereof, preferably a combination of PEG and PVP, such as 20-30 wt% PEG and 3-6 wt% PVP k10 in dope solution.

[0172] An additional pore former (A*) such as triethylene glycol (TEG), glycerol, cellulose acetate, a polyvinyl acetate, a polyvinyl alcohol, or any combination thereof may also be used in the polymeric dope solution.

[0173] The intended water filtration may be ultrafiltration or microfiltration, preferably ultrafiltration.

[0174] For such water filtration end-use (particularly ultrafiltration), the porous membrane is preferably casted from a NMP polymeric dope solution.- 25 - SSPU 2024 / 046

[0175] Hence, the porous membrane of the present invention intended for use in water filtration is preferably a hollow fiber membrane comprising the copolymer (P1), wherein the hollow fiber has an average thickness from 0.5 to 500 microns and is produced by spinning a dope solution comprising the copolymer (P1), polyethylene glycol (PEG) of molecular weight 200-900 g / mol and polyvinylpyrrolidone (PVP) of molecular weight 5,000-360,000 g / mol in dimethylacetamide (DMAc) or N- methylpyrrolidone (NMP). Preferably, the copolymer (P1) comprises at least 10 mol.% to at most 30 mol.% of the recurring units (R*PI) of formula (N1), the mol% being based on the total molar amount of recurring units in the copolymer (P1).

[0176] Polymeric composition

[0177] A second aspect of the present invention relates to a polymeric composition.

[0178] The polymeric composition may be used to make a porous membrane according to the invention.

[0179] The polymeric composition comprises the copolymer (P1).

[0180] The polymeric composition preferably comprises a combination of the copolymer (P1) and the PAES polymer (P2). The weight ratio of the copolymer (P1) to the PAES copolymer (P2) in the polymeric composition may be from 5:95 to 70:30, preferably from 10:90 to 60:40, more preferably from 15:85 to 50:50.

[0181] The polymeric composition may comprise a combination of the copolymer (P1) and the PAES polymer (P2), and at least one pore former (A). The amount of the at least one pore former (A) in such a polymeric composition may be from 20 parts by weight (pbw) to 200 pbw, preferably from 25 pbw to 180 pbw, relative to 100 pbw of the combined amounts of the copolymer (P1) and the PAES copolymer (P2).

[0182] In the polymeric composition according to the invention, any embodiments described herein for the copolymer (P1), the PAES polymer (P2), and the pore former (A) are applicable.

[0183] While the copolymer (P1) used in the polymeric composition may be sulfonated and / or carboxylated, the copolymer (P1) is preferably not sulfonated and / or not carboxylated. In particular, the copolymer (P1) in the polymeric composition may be such that substantially all of the recurring units of the copolymer (P1) (meaning at least 99 mol.% based on the total molar amount of recurring units of said copolymer (P1)) are the recurring unit (RPI) of formula (M1) and the recurring unit (R*PI) of formula (N1).

[0184] While the PAES polymer (P2) used in the polymeric composition may be sulfonated and / or carboxylated, the PAES polymer (P2) is preferably not sulfonated and / or not carboxylated.

[0185] Preferably the PAES polymer (P2) in the polymeric composition may be a PPSU polymer (P2) in which the recurring unit (RP2) is represented by formula (M1).- 26 - SSPU 2024 / 046

[0186] Alternatively, the PAES polymer (P2) in the polymeric composition may be a PES polymer (P2) in which the recurring unit (RP2) is represented by formula (M2b).

[0187] The polymeric composition may be in solid form such as powder, pellets, or granules, or in a form of a solution.

[0188] A particular preferred composition is a polymeric solution comprising a blend of the copolymer (P1) and PSSU (as PAES copolymer (P2)) both in soluble form in a solvent. In such instance, the preferred recurring unit (RPI) of the copolymer (P1) is of formula (M1) and the preferred recurring unit (R*PI) is of formula (N1); and the recurring unit (RP2) of the PPSU is represented by formula (M1).

[0189] Another particular preferred composition is a powder blend comprising the copolymer (P1) in powder form and PES (as PAES copolymer (P2)) in powder form. In such instance, the preferred recurring unit (RPI) of the copolymer (P1) is of formula (M1) and the preferred recurring unit (R*PI) is of formula (N1); the recurring unit (RP2) of the PES is represented by formula (M2b).

[0190] Polymeric solution

[0191] The polymeric composition when in form of a solution further comprises a solvent.Both the copolymer (P1) and the PAES copolymer (P2) are soluble in that solvent.

[0192] The polymeric solution may comprise the copolymer (P1) in an amount from 10 wt.% to 25 wt.%, preferably from 15 wt.% to 25 wt.%, more preferably from 16 wt.% to 23 wt.%, yet more preferably from 16 wt.% to 21 wt.% of the copolymer (P1), said wt.% being based on the total weight of the polymeric solution.

[0193] Preferably, the polymeric solution comprises the copolymer (P1) and the PAES polymer (P2).

[0194] The weight ratio of the copolymer (P1) to the PAES copolymer (P2) in the polymeric solution is from 5:95 to 70:30, preferably from 10:90 to 60:40, more preferably from 15:85 to 50:50.

[0195] More preferably, the polymeric solution comprises a combination of the copolymer (P1) and the PAES polymer (P2), and at least one pore former (A). The at least one pore former (A) is water soluble. To make such a solution, the copolymer (P1) and PAES copolymer (P2) in solid form, either as a blended powder or as separate powders, are dissolved in a solvent and the at least one pore former (A) is also added.

[0196] In the polymeric solution according to the invention, any embodiments described herein for the copolymer (P1), the PAES polymer (P2), and the pore former (A) are equally applicable.

[0197] The overall concentration of the copolymer (P1) and PAES copolymer (P2) in the polymeric solution should be at least 8 wt.%, preferably at least 10 wt.%, preferably at least 12 wt.%, based on the total weight of the solution. Typically the concentration of the copolymer (P1) and PAES copolymer (P2) in the polymeric- 27 - SSPU 2024 / 046solution does not exceed 40 wt.%, preferably it does not exceed 30 wt.%, more preferably it does not exceed 25 wt.%, yet more preferably it does not exceed 20 wt.%, based on the total weight of the polymeric solution.

[0198] The combined weights of the copolymer (P1) and PAES copolymer (P2) in the polymeric solution may be from 5 wt.% to 40 wt.% or from 8 wt.% to 40 wt.%, preferably from 8 wt.% to 35 wt.% or from 8 wt.% to 30 wt.%, more preferably from 10 wt.% to 25 wt.%, or from 12 wt.% to 25 wt.% , even more preferably from 13 wt.% to 24 wt.%, or from 14 wt.% to 24 wt.%, or from 15 wt.% to 23 wt.%, yet more preferably from 16 wt.% to 21 wt.%, said wt.% being based on the total weight of the polymeric solution.

[0199] A total concentration of the copolymer (P1) and the PAES copolymer (P2) ranging from 15 wt.% to 20 wt.% with respect to the total weight of polymeric solution has been found particularly advantageous to be used as a dope solution to make a porous membrane via solution casting or spinning.

[0200] While the copolymer (P1) used in the polymeric solution may be sulfonated and / or carboxylated, the copolymer (P1) is preferably not sulfonated and / or not carboxylated. In particular, the copolymer (P1) in the polymeric solution may be such that substantially all of the recurring units of the copolymer (P1) ) (meaning at least 99 mol.% based on the total molar amount of recurring units of said copolymer (P1)) are the recurring unit (RPI) of formula (M1) and the recurring unit (R*PI) of formula (N1).

[0201] While the PAES polymer (P2) used in the polymeric solution may be sulfonated and / or carboxylated, the PAES polymer (P2) is preferably not sulfonated and / or not carboxylated.

[0202] The PAES polymer (P2) in the polymeric solution is preferably a PPSU polymer (P2) in which the recurring unit (RP2) is the same as the recurring unit (RPI) of the copolymer (P1) and is represented by the formula (M1).

[0203] Pore former (A)

[0204] The polymeric solution comprising the copolymer (P1) and the PAES copolymer (P2) may further comprise at least one pore former (A).

[0205] The at least one pore former (A) in the polymeric solution may be selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”];at least one (poly)hydroxyl aliphatic alcohol having from 1 to 6 carbon atoms, preferably at least one glycerol compound, more preferably glycerol,- 28 - SSPU 2024 / 046at least one carboxylic acid comprising at least 3 carbon atoms, preferably propionic acid, butyric acid, and / or valeric acid;at least one polyvinyl alcohol;at least one polyvinyl acetate;cellulose acetate; andany combination thereof.

[0206] The polymeric solution preferably comprises at least one pore former (A) selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”]; and any combination thereof.

[0207] The amount of the at least one pore former (A) in the polymeric solution may be from 20 parts by weight (pbw) to 200 pbw, preferably from 25 pbw to 180 pbw, relative to 100 pbw of the combined amounts of the copolymer (P1) and the PAES copolymer (P2)

[0208] The one or more pore formers (A), when added to the polymeric solution, is / are present in amounts typically ranging from 0.5 wt.% to 40 wt.%, preferably from 1 wt.% to 40 wt.%, more preferably from 5 wt.% to 35 wt.%, yet more preferably from 10 wt.% to 30 wt.% or from 15 wt.% to 25 wt.%, said wt.% being based on the total weight of the polymeric solution.

[0209] As suitable pore former (A), (poly) hydroxy I aliphatic alcohols having from 1 to 6 carbon atoms or derivatives thereof may comprise or be at least one ethylene glycol compound and / or at least one glycerol compound.

[0210] The expression “ethylene glycol compound” is intended to encompass ethylene glycol, dimers and / or trimers thereof, as well as mono-ether and mono-ester derivatives, to the extent that the ethylene glycol compound comprises at least one free hydroxyl group. Preferred ethylene glycol compounds are selected from the group consisting of ethylene glycol, diethylene glycol (DEG), triethylene glycol (TEG), aliphatic mono-ethers and mono-esters, in particular methyl, ethyl or butyl monoethers and acetyl monoesters.

[0211] The expression “glycerol compound” is intended to encompass glycerol and dimers thereof, as well as mono-ether, di-ether, mono-ester and di-ester derivatives, to the extent that the glycerol compound comprises at least one free hydroxyl group.

[0212] As suitable pore former (A), preferred glycerol compounds are selected from the group consisting of glycerol, aliphatic mono- and di-esters thereof, in particular monoacetyl glycerol, di-acetyl glycerol, aliphatic mono- and di-ethers thereof, in particular- 29 - SSPU 2024 / 046methyl, ethyl or butyl mono-ethers or di-ethers, including notably mono-ter-butyl- glycerol, di-ter-butyl-glycerol; glycerol carbonate; glycerol acetals derived from aliphatic aldehydes, including butanal, pentanal, hexanal, octanal and decanal glycerol acetals.

[0213] As suitable pore former (A), a carboxylic acid comprising at least 3 carbon atoms is preferably selected from propionic acid, butyric acid, and / or valeric acid, more preferably propionic acid.

[0214] When the pore former (A) is a PVP, the PVP content in the polymeric solution may be from 2 wt.% to 10 wt.% PVP, preferably from 3 wt.% to 9 wt.% PVP, more preferably from 4 wt.% to 8 wt.% PVP, yet more preferably from 4 wt.% to 6 wt.% PVP, based on total weight of the polymeric solution. The PVP preferably has a molecular weight of from 5,000 g / mol to 360,000 g / mol.

[0215] When the pore former (A) is a PEG, the PEG content in the polymeric solution may be from 5 wt.% to 30 wt.% PEG, preferably from 10 wt.% to 40 wt.% PEG, more preferably from 15 wt.% to 35 wt.% PEG, yet more preferably from 20 wt.% to 35 wt.% PEG, even more preferably from 20 wt.% to 30 wt.% PEG, based on total weight of the polymeric solution. The PEG preferably has a formula weight from 200 to 900 g / mol.

[0216] When one or more PHAs having from 1 to 6 carbon are employed as pore former (A), their amounts generally should be at least 1% by weight, preferably at least 2% by weight, based on the total weight of the solution. Typically, the concentration of the PHAs in the solution does not exceed 20% by weight, preferably it does not exceed 15% by weight, more preferably it does not exceed 14% by weight, based on the total weight of the polymeric solution.

[0217] When the pore former (A) is glycerol, the glycerol content in the polymeric solution may be from 5 wt.% to 30 wt.% glycerol, preferably from 10 wt.% to 30 wt.% glycerol, more preferably from 15 wt.% to 30 wt.% glycerol, yet more preferably from 20 wt.% to 30 wt.% glycerol, based on total weight of the polymeric solution.

[0218] When the pore former (A) is a carboxylic acid comprising at least 3 carbon atoms, its content in the polymeric solution may be from 5 wt.% to 40 wt.%, preferably from 10 wt.% to 35 wt.%, more preferably from 15 wt.% to 30 wt.%, yet more preferably from 20 wt.% to 30 wt.%, based on total weight of the polymeric solution.

[0219] When propionic acid is used as pore former (A) in the polymeric solution, its amount is generally of from 10 to 40 wt.% or from 20 to 35 wt.%, or from 20 to 30 wt.%, with respect to the total weight of polymeric solution. In example, a polymeric solution having from 15 wt.% to 20 wt.% of copolymer (P1) and polymer (P2) may be made with a blend of the solvent (e.g., DMAc, DMF, or NMP) and propionic acid with a- 30 - SSPU 2024 / 046vol / vol ratio of from 50:50 to 95:5, preferably from 60:40 to 80:20, more preferably from 65:35 to 75:25, yet more preferably about 70:30.

[0220] The polymeric solution may alternatively exclude pore formers (A) selected from carboxylic acids comprising at least 3 carbon atoms, and particularly may exclude propionic acid as pore former (A).

[0221] When the polymeric solution comprises a combination of two or more pore formers (A), the combined amount of pore formers (A) in the polymeric solution should not exceed 35 wt.%, preferably should not exceed 30 wt.%, said wt.% being based on the entire weight of the polymeric solution.

[0222] When the polymeric solution comprises a combination of two or more pore formers (A), preferred combinations of pore formers (A) are as follows:- a combination of a PVP and a PEG,- a combination of a PVP, a PEG, and glycerol;- a combination of a PVP, a PEG, and propionic acid;- a combination of a PVP and glycerol;- a combination of a PVP and propionic acid;- a combination of a PEG and glycerol; or- a combination of a PEG and propionic acid.

[0223] When the polymeric solution comprises a combination of two or more pore formers (A), a more preferred combination of pore formers (A) is a combination of a PVP and a PEG.

[0224] A polymeric solution comprising a combination of the copolymer (P1) and the PAES polymer (P2), and at least one pore former (A) can be advantageously used to make a porous membrane according to the invention, particularly an ultrafiltration membrane for water purification or a hollow fiber membrane for water filtration and hemodialysis application.

[0225] Solvent in polymeric solution

[0226] The polymeric solution further comprises at least a solvent in which the copolymer (P1) and the PAES polymer (P2) are soluble.

[0227] The term “solubility” or “soluble” is defined herein as the maximum amount of polymer, measured in terms of weight of the polymer per weight of solution, which dissolves at a given temperature affording a transparent homogeneous solution without the presence of any phase separation in the system. The ‘polymer’ in such a definition refers to the copolymer (P1), the PAES polymer (P2), or the blend of copolymer (P1) and PAES polymer (P2).

[0228] The polymeric solution comprises a solvent selected from the group consisting of N- methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl isosorbide (DMI), N,N-dimethylacetamide (DMAc), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate- 31 - SSPU 2024 / 046(Rhodiasolv® Polar-clean), gamma-valerolactone (GLV), N-butylpyrrolidone (NBP), N- ethyl-2-pyrrolidone (NEP), cyrene, e-caprolactam, butyrolactone, 1 ,3-dimethyl-2- imidazolidinone, tetra hydrofuran (THF), dimethyl sulfoxide (DMSO), chlorobenzene, sulfolane, N,N-dimethyl lactamide (AMD), and any combination of two or more thereof.

[0229] A suitable A / ,A / -dimethyl lactamide (AMD) is available under the tradename Agnique® from BASF - see an example of its use in making a PES hollow fiber via nonsolvent- induced phase separation Uebele et al., Journal of Applied Polymer Science (2021 ) 138, e509935.

[0230] The solvent in the polymeric solution is preferably selected from the group consisting of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl isosorbide (DMI), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), methyl 5- (dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polar-clean), gamma- valerolactone (GLV), e-caprolactam, butyrolactone, and any combination of two or more thereof.

[0231] The solvent in the polymeric solution is more preferably selected from the group consisting of NMP, DMF, DMI, DMAc, DMSO, and any combination of two or more thereof.

[0232] The concentration of the solvent in the polymeric solution may be at least 20 wt.%, at least 30 wt.%, or at least 40 wt.%, based on the total polymer solution weight and / or is at most 80 wt.%; at most 75 wt.%; at most 70 wt.%; at most 65 wt.%; at most 60 wt.%, or at most 55wt.%; based on the total polymer solution weight.

[0233] Optional co-solvent in polymeric solution

[0234] At least one co-solvent may be also present, in addition to the main solvent described above, in the polymeric solution of the present invention. Examples of co-solvent may be benzyl alcohol, C1-C6 alcohols such as ethanol, isopropyl alcohol, and / or sulfolane in instance when sulfolane is not used as the main solvent in the polymeric solution. The concentration of the co-solvent may be from 0.5 wt.% to 15 wt. % based on the total polymer solution weight.

[0235] When the solution contains both at least one solvent and at least one co-solvent, the total concentration of the solvents) and co-solvent(s) in the polymeric solution may be at least 20 wt.%, at least 30 wt.%, or at least 40 wt.%, based on the total polymer solution weight and / or is at most 80 wt.%; at most 70 wt.%; or at most 60 wt.%, based on the total weight of polymeric solution.

[0236] Optional additive(s) in polymeric solution

[0237] The polymeric solution may further comprise water.

[0238] In such instance, the water content in the polymeric solution may be from 0.3 wt.% to 10 wt.%, preferably from 0.3 wt.% to 9 wt.%, more preferably from 0.4 wt.% to 8 wt.%, yet more preferably from 0.5 wt.% to 6 wt.%, based on total weight of the polymeric- 32 - SSPU 2024 / 046solution.

[0239] The polymeric solution may contain additional components, such as nucleating agents, fillers and the like. Alternatively, the polymeric solution may exclude additional components, such as nucleating agents, fillers and the like.

[0240] Process for making the copolymer (P1 )

[0241] The copolymer (P1) can be made by condensation in a reaction medium of at least one dianhydrohexitol monomer (AA) and 4,4’-biphenol co-diol monomer (BB) with at least one dihaloary I sulfone monomer (CC) comprising at least one -S(=O)2- group.

[0242] The process preferably comprises reacting the at least one dianhydrohexitol monomer (AA), biphenol co-diol (BB), and the at least one dihaloary I sulfone monomer (CC) in a reaction medium comprising a polar aprotic solvent and a base.

[0243] The reaction medium may further comprise another dihaloary I sulfone monomer (CC’) which is substituted.

[0244] The molar ratio of monomer (AA) to the biphenol co-diol (BB) may be from 5 / 95 to 80 / 20, preferably from 10 / 90 to 70 / 30, more preferably from 10 / 90 to 65 / 35, yet more preferably from 10 / 90 to 60 / 40, still more preferably from 10 / 90 to 50 / 50, even more preferably from 10 / 90 to 40 / 60, most preferably from 10 / 90 to 30 / 70

[0245] The molar ratio of halogen groups (preferably chlorine) and the hydroxyl groups in the reaction medium can vary, depending on factors such as control of the end group types and contents or control of reaction speed and sulfone polymer molecular weight. It is generally preferred that the molar ratio of the hydroxyl groups of the diol monomers (AA) and (BB) and the halogen groups of the dihaloaryl sulfone monomer (CC) and optional other dihalogenated monomer (CC’) which are reactive towards each other is controlled or adjusted.

[0246] The molar ratio between the overall amount of hydroxyl groups from the diols (AA) and (BB) and the overall amount of halogen groups from the dihaloaryl sulfone monomer (CC) and optional monomer (CC’) in the reaction medium is generally from 0.95 to 1.05, preferably from 0.98 to 1.02, more preferably from 0.985 to 1.015, yet more preferably from 0.99 to 1.01. Values of molar ratios of the overall amount of hydroxyl groups to the overall amount of halogen groups of from 0.995 and 1.008, or from 0.997 and 1.007, are particularly advantageous to achieve high Mw of greater than 50 kDa.

[0247] While the molar ratio of the hydroxyl groups and halogen groups is preferably substantially equimolar with respect to obtaining higher molecular weights (Mw > 50 kDa), alternatively the molar ratio of the halogen groups (preferably chlorine) can be higher than that of the hydroxyl groups or vice versa. For instance, to increase the number of phenolic OH end groups, the molar ratio of halogen (chlorine) end groups to phenolic OH end groups is adjusted by using a molar excess of the starting diols- 33 - SSPU 2024 / 046(AA) and (BB) compared to the starting dihaloary I sulfone monomer (CC) and optional monomer (CC’). For example, the molar ratio of OH groups to halogen (chlorine) groups may be from 1.005 to 1.2, especially from 1.007 to 1.15, most preferably from 1.01 to 1.1.

[0248] When it is desired to have less reactive end groups in the copolymer (P1), it may be preferred to increase the number of halogen (chlorine) end groups, in particular phenyl chlorine, and the molar ratio of halogen (chlorine) end groups to phenolic OH end groups is adjusted by using a molar excess of the starting dihaloaryl sulfone monomer (CC) and optional (CC’) compared to the starting diols (AA) and (BB), whereby an excess of chlorine end groups is preferable. In such instance, the molar ratio of halogen (chlorine) groups to OH groups may be from 1.005 to 1.2, especially from 1.007 to 1.15, most preferably from 1.01 to 1.1.

[0249] The reaction medium in which the polycondensation reaction is carried out has a total weight % monomer concentration [hereinafter “total wt% monomers”] based on the total weight of the diols (AA), (BB) dihaloaryl sulfone monomer (CC), optional monomer (CC’) and the polar aprotic solvent, of:- at least 30 wt%, preferably at least 35 wt%, more preferably at least 38 wt%, and / or - at most 60 wt%, preferably at most 55 wt%, more preferably at most 50 wt%.

[0250] Dianhydrohexitol monomer (AA)

[0251] The at least one dianhydrohexitol monomer (AA) may be selected from 1 ,4:3,6- dianhydrohexitols and / or 1 ,4:3,6-dianhydrohexitols with acyclic aliphatic end groups.

[0252] The at least one dianhydrohexitol monomer (AA) is preferably selected from the group consisting of those complying with formulae (D1) (D2), (D3) and (D4) :(D4), andany combination thereof,wherein each Q’, being the same or different in formula (D4), is an acyclic moiety.

[0253] The acyclic moiety Q’ in formula (D4) may be derived from an acyclic diol selected from alkylene oxides and / or poly(alkylene oxide)s, preferably selected from the group- 34 - SSPU 2024 / 046consisting of ethylene glycol; propylene glycol [HO-CH2-CH(CH3)-OH]; 1 ,3- propanediol; 1 ,4-butanediol; 1 ,5-pentanediol; 1 ,6-hexanediol; 1 ,8-octanediol; 1 ,10- decanediol; 2-methyl-1,3-propanediol; 2,2-dimethylpropane-1 ,3-diol; 2,2,4-trimethyl- 1 ,3-pentanediol; 2-ethy l-2-buty 1-1 ,3-propanediol; poly(ethylene glycol); polypropylene glycol); poly(tetramethylene oxide); and any combination of two or more thereof.

[0254] Q’ in formula (D4) may be represented by formula (VI): -[Rk-O-]z-Rk-,in which Rk is selected from alkylenes, preferably alkylenes having from 1 to 10 carbon atoms, more preferably selected from the group consisting of methylene [CH2], ethylene [CH2-CH2], isopropylene [CH2-CH(CH3)], tetramethylene [CH2-CH2- CH2-CH2], 2,2-dimethylpropylene [CH2-C(CH3)2-CH2], 2-ethyl-2-butyl-1,3-propylene [CH2-C(C2H5)(C4H9)-CH2], 2,2,4-trimethyl-1 ,3-pentylene [CH(C(CH3)2)-C(CH3)2-CH2], and any combination thereof; and z is 0 or an integer from 1 to 500, preferably an integer from 2 to 200, more preferably an integer from 2 to 100, yet more preferably an integer from 2 to 50;preferably, represented by any one of following formulae (VI’), (VI”), (VI’”) and (VI””): -[CH2-CH2-O]Z-CH2-CH2- (VI’),-[CH2-CH(CH3)-O]Z-CH2-CH(CH3)- (VI”),-[CH2-CH2-CH2-CH2-O]Z-CH2-CH2-CH2-CH2- (VI’”),-[CH2-C(CH3)2-CH2-O]Z-CH2-C(CH3)2-CH2- (VI””),in which z is 0 or an integer from 1 to 500, preferably an integer from 2 to 200, more preferably an integer from 2 to 100, yet more preferably an integer from 2 to 50.

[0255] The at least one dianhydrohexitol monomer (AA) is more preferably isosorbide of formula (D1).

[0256] 4,4’-biphenol co-diol monomer (BB)

[0257] The reaction medium comprises 4,4’-biphenol monomer (BB) of formula (B):

[0258] Dihaloaryl sulfone monomer (CC)

[0259] The reaction medium comprises at least one dihaloaryl sulfone monomer (CC) of formula (C):wherein X and X’, independently of each other, are halogen selected from Cl and / or F, preferably both X, X’ being Cl.- 35 - SSPU 2024 / 046

[0260] The dihaloary I sulfone monomer (CC) more preferably consists essentially of: 4,4’- dichlorodiphenyl sulfone (DCDPS), 4,4’ difluorodiphenyl sulfone (DFDPS), and any combination thereof.

[0261] Optional substituted dihaloaryl sulfone monomer (CC’)

[0262] The reaction medium may further comprise at least one substituted dihaloaryl sulfone monomer (CC’) of formula (C’):wherein:X and X’, independently of each other, are halogen selected from Cl and / or F, preferably both X, X’ being Cl;each R is selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate; andeach i is an integer from 0 to 4, with the proviso that at least one i is not zero, preferably each i is 1.

[0263] When at least one i is 1 in formula (C’), then its corresponding R may be preferably selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, and alkyl phosphonate, more preferably selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, and alkyl phosphonate.

[0264] When the reaction medium further comprises at least one substituted dihaloaryl sulfone monomer (CC’) of formula (C’), such monomer (CC’) is preferably selected from the group consisting of: monosulfonated 4,4’-dichlorodiphenyl sulfone (msDCDPS), disulfonated 4,4’-dichlorodiphenyl sulfone (dsDCDPS), monosulfonated 4,4’ difluorodiphenyl sulfone (msDFDPS), disulfonated 4,4’ difluorodiphenyl sulfone (dsDFDPS), and any combination thereof.

[0265] Particularly, the reaction medium comprises DCDPS as monomer (CC) and optionally disodium bis(4-chloro-3-sulfophenyl)sulfone (dsDCDPS) as monomer (CC’).

[0266] Polar aprotic solvent- 36 - SSPU 2024 / 046

[0267] The reaction medium comprises a polar aprotic solvent.

[0268] The polar aprotic solvent employed is one generally known in the art and widely used for the manufacture of aromatic sulfone polymers. For example, sulfur containing solvents known and generically described in the art as dialkyl sulfoxides and dialkyl sulfones wherein the alkyl groups may contain from 1 to 8 carbon atoms, including cyclic alkylidene analogs thereof, are disclosed in the art for use in the manufacture of PAES. Specifically, among the sulfur-containing solvents that may be suitable for the purposes of this invention are dimethylsulfoxide, dimethylsulfone, diphenylsulfone, diethylsulfoxide, diethylsulfone, diisopropylsulfone, tetrahydrothiophene-1 , 1-dioxide (commonly called tetramethylene sulfone or sulfolane) and tetrahydrothiophene-1 -monoxide and mixtures thereof. Nitrogencontaining polar aprotic solvents, including N,N-dimethylacetamide (DMAc), N,N- dimethylformamide (DMF) and N-methyl pyrrolidone (NMP) and the like have been disclosed in the art for use in these processes, and may also be found useful in the practice of this invention.

[0269] The polar aprotic solvent is preferably selected from the group consisting of 1 ,3- dimethyl-2-imidazolidinone (DMI), dimethylsulfoxide (DMSO), dimethylsulfone (DMSO2), diphenylsulfone, diethylsulfoxide, diethylsulfone, diisopropylsulfone, tetrahydrothiophene-1 , 1-dioxide (commonly called tetramethylene sulfone or sulfolane), N-Methyl-2-pyrrolidone (NMP), N-butylpyrrolidone (NBP), N- ethylpyrrolidone (NEP), N,N-dimethylacetamide (DMAc), N,N' - dimethylpropyleneurea (DMPU), N,N’-dimethylformamide (DMF), N- methylcaprolactame, N-ethylcaprolactame, tetrahydrothiophene-1 -monoxide, and any mixture of two or more thereof.

[0270] The polar aprotic solvent is more preferably selected from the group consisting of N- methylpyrrolidone (NMP), N-butylpyrrolidone (NBP), N-ethyl-2-pyrrolidone, N,N- dimethylformamide (DMF), N,N’-dimethylacetamide (DMAc), 1 ,3-dimethyl-2- imidazolidinone (DMI), tetra hydrofuran (THF), dimethyl sulfoxide (DMSO), sulfolane, and any combination thereof.

[0271] The polymerization reaction to prepare the copolymer (P1) is more advantageously carried out in the polar aprotic solvent being sulfolane, DMAc or NMP.

[0272] Optional co-solvent

[0273] For the purpose of the present invention, the term “additional solvent” or “co-solvent” is understood to denote a solvent different from the reactants and the products of the polycondensation.

[0274] If desired, an additional solvent can be used together with the polar aprotic solvent which forms an azeotrope with water, whereby water that can originate from at least one raw material (for example the inorganic metal phosphate) and / or can be formed- 37 - SSPU 2024 / 046as a byproduct during the polymerization (for example when an alkali metal carbonate co-base is used) may be removed by azeotropic distillation continuously throughout the polymerization. In general, the reaction medium may be maintained in substantially anhydrous conditions during the polymerization by removing water continuously from the reaction mass. Water can be removed by distillation or with the azeotrope-forming solvent as an azeotrope, as described above.

[0275] The additional solvent that forms an azeotrope with water will generally be selected to be inert with respect to the monomer components and polar aprotic solvent.Suitable azeotrope-forming solvents for use in such polymerization processes include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, chlorobenzene and the like.

[0276] The azeotrope-forming solvent and polar aprotic solvent are typically employed in a weight ratio of from about 1 : 20 to about 1 : 1 , preferably from about 1 : 10 to about 1 : 1 , more preferably from about 1 : 5 to about 1 : 3.

[0277] Base

[0278] The base in the reaction medium comprises or consists of an anhydrous alkali metal carbonate.

[0279] The anhydrous alkali metal carbonate may be selected from the group consisting of sodium carbonate, potassium carbonate, rubidium carbonate and cesium carbonate, preferably selected from sodium carbonate and / or potassium carbonate, more preferably potassium carbonate.

[0280] The average particle size (D50) of the alkali metal carbonate may be at least 10 microns and at most 400 microns, preferably at least 15 microns and at most 200 microns, more preferably at least 20 microns and at most 100 microns. Even more preferably, the alkali metal carbonate’s average particle size (D50) of at least 20 microns and at most 50 microns is used.

[0281] When the process for making copolymer (P1) is carried out in the presence of anhydrous K2CO3, the anhydrous K2CO3 may have a volume-averaged particle size (D[4,3]) of less than about 100 pm, for example less than 45 microns, less than 30 microns or less than 20 microns. In particular, the process is carried out in in the presence of a carbonate component comprising not less than 50 wt% of K2CO3 having a volume-averaged particle size of less than about 100 microns, for example less than 45 microns, less than 30 microns or less than 20 microns, based on the overall weight of the carbonate component in the reaction medium. The volume- averaged particle size of the carbonate used can for example be determined with a Mastersizer 2000 from Malvern on a suspension of the particles in chlorobenzene / sulfolane (60 / 40).- 38 - SSPU 2024 / 046

[0282] As used herein, the term “anhydrous” refers to a substance containing less than 2 wt% moisture, preferably less than 1% moisture, more preferably less than 0.5% moisture, most preferably less than 0.25% moisture as measured by Karl-Fisher titration or by loss on drying test.

[0283] The base does not include a strong hindered potassium base, such as potassium trimethylsilanolate. For example, the strong hindered base disclosed in W02020 / 201522 (Roquette Freres) is not present in the base.

[0284] The base preferably does not include an organic base.

[0285] Other than the alkali metal carbonate present in the base which participates in the polycondensation reaction, the base does not comprise any organic catalyst. For example, the crown-ether catalyst disclosed in EP3653661A1 (Korea Research Institute of Chemical Technology) is not present in the base.

[0286] Polymerization conditions

[0287] The reaction medium to prepare the copolymer (P1) is kept at a temperature suitable for polycondensation to occur. Such a suitable temperature for the reaction medium may be:- more than 110 °C, preferably at least 115 °C, more preferably at least 120 °C, yet more preferably at least 125 °C, and- less than 210 °C, preferably at most 205 °C, more preferably at most 200 °C, yet more preferably at most 195 °C.

[0288] Preferred temperature of the reaction medium may be from about 115°C to about 205°C, preferably from about 120 °C to about 200 °C, when NMP and / or sulfolane is used as solvent.

[0289] Preferred temperature of the reaction medium may be from about 115°C to about 175°C, preferably from about 120°C to about 175°C, when DMAc is used as solvent.

[0290] When NMP and / or sulfolane is used as polar aprotic solvent, the temperature of the reaction medium may be from about 150°C to about 205°C, preferably from about 160°C to about 200°C.

[0291] When DMAc is used as polar aprotic solvent, the temperature of the reaction medium may be from about 155°C to about 175°C, preferably from about 160°C to about 175°C.

[0292] The process to manufacture the copolymer (P1) is such that the reaction conversion is at least 90%, preferably at least 95%.

[0293] The time for reaction to prepare the copolymer (P1) may be from about 3 hours to 24 hours, or from about 4 hours to 20 hours, or from 5 hours to 18 hours.

[0294] Typically, if the reaction is conducted at atmospheric pressure, the boiling temperature of the solvent selected usually limits the temperature of the reaction.- 39 - SSPU 2024 / 046The reaction may be conveniently carried out in an inert atmosphere, e. g., nitrogen, at atmospheric pressure, although higher or lower pressures may also be used.

[0295] Termination of polymerization

[0296] Once the desired molecular weight of the polymer is achieved, a polar aprotic solvent (same or different than the solvent used during polymerization) may be added (this serves as cooling the reaction medium to stop reaction).

[0297] The polycondensation may be terminated by using an end-capping agent such as an alkyl halide (particularly preferred methyl chloride), bubbling through the reaction medium. The end-capping step converts the reactive -OH end groups into non- reactive alkoxy end groups. For examples, when methyl chloride is used as endcapping agent, the -OH end groups are converted to methoxy (-OCH3) end groups.

[0298] After the polycondensation is terminated, the copolymer (P1) is separated from the inorganic constituents (for example sodium chloride or potassium chloride and / or excess of base) by suitable methods such as dissolving and filtering, screening or extracting to obtain a copolymer (P1) solution. Filtration can for example be used to separate the copolymer (P1) solution from the other components.

[0299] Recovery of copolymer (P1) in solid form

[0300] The copolymer (P1) can be recovered from the copolymer (P1) solution after separation of salts with or without first adding additional solvents) to fully dissolve any polymer and cause the precipitation of the metal halide (preferably KCI), by methods well known and widely employed in the art such as, for example, coagulation, solvent evaporation and the like.

[0301] The resulting copolymer (P1) may be isolated by devolatilization of the copolymer (P1) solution.

[0302] Preferably, the copolymer (P1) is isolated by precipitation and / or coagulation by contacting the copolymer (P1) solution, preferably after salt removal by filtration, with a non-solvent (in which the copolymer (P1) is not soluble) such as a C1-C5 alcohol, water, or any mixture thereof. The preci pitate / coag ulate may be rinsed and / or washed with demineralized water or a C1-C5 alcohol prior to drying at a temperature ranging from at least 70 °C to about 170 °C. While a vacuum may be applied during drying, drying is generally performed at ambient pressure.

[0303] The dried copolymer (P1) solid may be further processed by extruding and pelletizing. The pelletized product may subsequently be subjected to further melt processing such as injection molding and / or sheet extrusion. The conditions for molding, extruding, and thermoforming the resulting copolymer (P 1 ) are well known in the art.

[0304] The dried copolymer (P1) solid is preferably used to make a polymer dope solution suitable for making the porous membrane according to the invention.- 40 - SSPU 2024 / 046

[0305] The copolymer (P1) features all the benefits of the currently sold polyarylethersulfones while also featuring a reduced content in potential endocrine disruptors because 4,4’-biphenol has a much lower endocrine activity in comparison to bisphenols A and S, and potentially a higher renewable content especially because the dianhydrohexitol diol, preferably isosorbide of formula (D1), used in making the copolymer (P1) is bio-sourced.

[0306] Process for making the porous membrane

[0307] Another aspect of the present invention provides a method for making the porous membrane, such as porous film, hollow fiber, hollow tube or porous sheet, described herein.

[0308] The porous membrane according to the present invention can be made using any of the conventionally known preparation methods.

[0309] The method for making the porous membrane may include using a phase inversion technique selected from nonsolvent induced phase separation or thermally induced phase separation. Such use may include casting or spinning a polymeric solution containing the copolymer (P1) or a combination of copolymer (P1) and PAES polymer (P2), a solvent, optionally a co-solvent and optionally at least one pore former (A), as described previously, into the porous membrane, which is then cooled or contacted with a non-solvent.

[0310] Various techniques suitable for making the article according to the invention may be found in the book by Chang Dae Han entitled “Rheology and Processing of Polymeric Materials”, Vol. 2 (2007), Oxford press, such as in Chapter 2:Plasticating Single-Screw Extrusion (pages 56-131), Chapter 6: Fiber Spinning (pages 257-302) and Chapter 8: Injection molding (pages 351-378).

[0311] The method for making the porous membrane preferably includes casting or spinning a polymeric solution (sometimes referred to as “polymer dope solution”) into a preformed article (such as film, fiber, tube, membrane, layer) which is then cooled and / or contacted with a non-solvent. The polymer dope solution comprises the copolymer (P1) or a combination of copolymer (P1) and PAES polymer (P2), the solvent in which the copolymer (P1) and the PAES polymer (P2) are soluble, optionally a cosolvent and optionally at least one pore former (A).

[0312] Preferably, the copolymer (P1) and optionally the PAES polymer (P2) are the sole aromatic sulfone polymers in the polymer dope solution.

[0313] When the porous membrane is a flat film, the polymer dope solution may be casted as a film over a flat supporting substrate, typically a plate, a belt or a fabric, or a microporous supporting membrane, typically by means of a casting knife, a drawdown bar or a slot die.- 41 - SSPU 2024 / 046

[0314] Alternatively, the polymer dope solution may be spun in the form of a tubular film.The tubular film may be manufactured using a spinneret, this technique being otherwise generally referred to as "spinning method". Hollow fibers and capillary membranes may be manufactured according to the spinning method. The term “spinneret” is hereby understood to mean an annular nozzle comprising at least two concentric capillaries: a first outer capillary for the passage of the polymer solution and a second inner (generally referred to as “lumen”) for the passage of a supporting fluid, also referred to as “bore fluid”.

[0315] For the non-solvent induced phase separation (NIPS), the pre-formed article is contacted with a non-solvent medium (medium [NS]) thereby providing a porous membrane. Such step of contacting with a medium [NS] is generally effective for precipitating and coagulating the polymer(s) (being the copolymer (P1) or a combination of (P1) and (P2)) constituting the pre-formed article into a porous membrane. The polymer(s) (being the copolymer (P1) or a combination of (P1) and (P2)) may be precipitated in said medium [NS] by immersion in a coagulation bath containing a non-solvent medium [NS]. In some instances, the coagulation bath containing at least one non-solvent medium [NS] may also contain a solvent at the beginning of the coagulation, for example from 5 wt.% to 70 wt.% solvent or from 10 wt.% to 70 wt.% solvent, or from 20 wt.% to 60 wt.% solvent, or from 30 wt.% to 50 wt.% solvent, said wt.% being based on the total weight of the coagulation bath. The solvent content provided in the bath corresponds to the initial solvent concentration right before coagulation is started.

[0316] The coagulation bath preferably comprises a non-solvent selected from water at least one alcohol and / or at least one polyalcohol, such as aliphatic alcohols having a short chain, for example from 1 to 6 carbon atoms, preferably methanol, ethanol, isopropanol, glycerol, ethylene glycol, diethylene glycol and / or triethylene glycol. The solvent in which the polymers (P1) and (P2) are soluble, in the coagulation bath may be selected from, but not limited to, NMP, DMF, dimethyl isosorbide (DMI), DMAc, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polar-clean), gamma-valerolactone (GLV), NBP, NEP, cyrene, e-caprolactam, butyrolactone, 1 ,3- dimethyl-2-imidazolidinone, THF, DMSO, chlorobenzene, sulfolane, N,N-dimethyl lactamide (AMD), or any combination of two or more thereof. The solvent present in the coagulation bath at the onset of the coagulation preferably comprises or consists essentially of NMP, DMF, dimethyl isosorbide (DMI), DMAc, DMSO, methyl 5- (dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polar-clean), gamma- valerolactone (GLV), or any combination of two or more solvents. The solvent present in the coagulation bath at the onset of the coagulation more preferably- 42 - SSPU 2024 / 046comprises or consists essentially of NMP, DMF, DMAc, DMSO, or any combination of two or more thereof.

[0317] The coagulation in the NIPS technique typically takes place in the coagulation bath at a temperature generally ranging from 15°C to 60°C, preferably from 20°C to 60°C, more preferably from 25°C to 50°C.

[0318] Alternatively (or usually before immersing in a coagulation bath), contacting the preformed article with medium [NS] may be accomplished by exposing it to a gaseous phase comprising vapors of such medium [NS]. This technique is termed “VIPS” for vapor induced phase separation. This typically takes place in a climatic chamber into which the pre-formed article is introduced in the climatic chamber set at a temperature generally ranging from 20°C to 40°C, preferably at about 35°C and a relative humidity of from 50 to 80% RH, preferably at about 60% of humidity.

[0319] For the purpose of the present invention, the term “non-solvent” [NS] is intended to mean a medium consisting of one or more liquid substances incapable of dissolving the polymers (P1) and (P2), and which advantageously promotes the coagulation / precipitation of the polymers (P1) and (P2) from the polymeric solution (polymer dope solution). The medium (NS) typically comprises water and / or at least one alcohol or polyalcohol, preferably aliphatic alcohols having a short chain, for example from 1 to 6 carbon atoms, more preferably methanol, ethanol, isopropanol, glycerol, triethylene glycol, diethylene glycol, and / or ethylene glycol.

[0320] For a thermally induced phase separation (“TIPS”), coagulation / precipitation of the sulfone polymers (P1) and (P2) may be promoted by cooling. In this case, the cooling of the pre-formed article may be typically carried out using any conventional techniques. Generally, when the coagulation / precipitation is thermally induced, the solvent in the polymeric solution is advantageously a “latent” solvent (solvent (LT)), i.e. a solvent which behaves as an active solvent towards the polymers (P1) and (P2) only when heated above a certain temperature, and which is not able to solubilize the polymers (P1) and (P2) below such temperature. When the polymeric solution comprises a latent solvent, the pre-shaping step (e.g., casting) for the making of the membrane is generally carried out at a temperature high enough to maintain the polymeric solution as a homogeneous solution. Cooling may be achieved by contacting the pre-formed article with a cooling fluid, which may be a gaseous fluid (i.e. cooled air or cooled modified atmosphere) or may be a liquid fluid. In this latter case, it is usual to make use of non-solvent medium [NS] as above detailed, so that the techniques of non-solvent-induced and thermally-induced precipitation may occur simultaneously. It is nevertheless generally understood that even in circumstances where the precipitation of the polymers (P1) and (P2) is induced thermally, a further step of non-solvent-induced precipitation, that is to say, contacting with non-solvent- 43 - SSPU 2024 / 046medium [NS], is carried out, e.g. for finalizing the polymers’ precipitation and facilitating removal of the solvent(s).

[0321] In cases where the polymeric solution comprises both solvent and non-solvent for the sulfone polymers (P1) and (P2), at least partially selective evaporation of the solvent may be used for promoting coagulation / precipitation of both polymers (P1) and (P2). In this case, solvent and non-solvent are typically selected so as to ensure the solvent having higher volatility than the non-solvent, so that progressive evaporation, generally under controlled conditions, of the solvent leads to the precipitation of the polymers (P1) and (P2), and hence actual contact of the pre-formed article with nonsolvent medium.

[0322] When present in the polymeric solution, a pore former (A) is generally at least partially, if not completely, removed from the porous membrane in the non-solvent medium [NS], during this step of the method for porous membrane manufacture.

[0323] The method may further include additional treatment steps after shaping and precipitation / coagulation, for instance steps of rinsing and / or stretching the porous membrane and / or a step of drying the porous membrane.

[0324] For instance, the porous membrane may be additionally rinsed, preferably with deionized water.

[0325] Further, the porous membrane may be advantageously stretched so as to increase its average porosity.

[0326] The porous membrane may be advantageously stored in water (storing medium) so as to maintain it in a wet form.

[0327] The porous membrane may be advantageously stored in water plus glycerol (storing medium), with preferably from 5 wt.% to 20 wt.% glycerol based on total weight of storing medium (water + glycerol) and then dried at room temperature.

[0328] The porous membrane may be dried from its storing medium, either water or water+glycerol, at a temperature of advantageously at least 30°C. Drying can be performed under air or a modified atmosphere, e.g., under an inert gas, typically exempt from moisture (water vapor content of less than 0.001 % v / v) after their wetting in isopropyl alcohol or alcohol. Drying can alternatively be performed under vacuum.

[0329] A suitable example of a method for forming a porous membrane from a polyarylethersulfone polymer is described in US2019 / 054429A1 (Solvay Specialty Polymers USA), incorporated herein by reference.

[0330] End-use applications of the porous membrane

[0331] The porous membrane according to the present invention is particularly intended for contact with an aqueous medium. The aqueous medium may include or may be a biological fluid (e.g., whole blood, plasma, serum, fractionated blood components or- 44 - SSPU 2024 / 046mixtures thereof), a beverage product (e.g., fruit juice, milk, beer), water, wastewater, or any aqueous industrial process water stream (e.g., process water, cooling water).

[0332] In particular, the porous membrane may be used :- for medical applications such as hemodialysis membranes,- for polymer electrolyte membranes,- for aqueous medium filtration, such as reverse osmosis membranes, ultrafiltration membranes, microfiltration membranes, nanofiltration membranes, and / or ionexchange membranes.

[0333] Both microfiltration and ultrafiltration membranes can be used in membrane bioreactors, such as wastewater treatment. Membranes may be in flat sheet or hollow fiber configuration.

[0334] The aqueous medium filtration may include food and beverage filtration, filtration for water purification, filtration for wastewater treatment and filtration for industrial process separations involving aqueous medium. Among applications of use, mention can be made of healthcare applications, in particular medical applications such as hemodialysis, wherein the porous membrane can advantageously be used in singleuse or may be reusable.

[0335] Method for purifying an aqueous medium

[0336] A further aspect of the present invention may be directed to a method for purifying an aqueous medium, said method comprising at least a filtration step through the porous membrane according to the present invention.

[0337] Indeed the inventive porous membrane can be used in different filter membrane geometries. For instance, the porous membrane can be used in flat membranes and / or in capillary-like hollow fiber membranes. The aqueous medium flow toward such a porous membrane may take in the form of a dead-end flow or of a crossflow.

[0338] In particular, the purification method may be used for purifying a human biological fluid, preferably a blood product, e.g., whole blood, plasma, serum, fractionated blood components or mixtures thereof. Such a purification is preferably carried out in an extracorporeal circuit which may comprise at least one filtering device (or filter) comprising at least one porous membrane as described above.

[0339] As intended herein, a blood purification method through an extracorporeal circuit may comprise hemodialysis (FD) by diffusion, hemofiltration (HF), hemodiafiltration (HDF) and / or hemoconcentration. In HF, blood is filtered by ultrafiltration, while in HDF blood is filtered by a combination of FD and HF.

[0340] Blood purification methods through an extracorporeal circuit are typically carried out by means of a hemodialyzer, i.e., equipment designed to implement any one of FD, HF or HFD. In such methods, blood is filtered from waste solutes and fluids, like urea,- 45 - SSPU 2024 / 046potassium, creatinine and uric acid, thereby providing blood free of waste solutes and fluids.

[0341] Typically, a hemodialyzer for carrying out a blood purification method comprises a cylindrical bundle of hollow fibers of porous membranes, said bundle having two ends, each of them being anchored into a so-called potting compound, which is usually a polymeric material acting as a glue which keeps the bundle ends together. Potting compounds are known in the art and include notably polyurethanes. By applying a pressure gradient, blood is pumped through the (lumen side of the) bundle of fibers via the blood ports and the filtration product (the "dialysate") is pumped through the space surrounding the fibers (shell side).

[0342] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0343] EXAMPLES

[0344] The invention will now be described with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the invention. As used in the Examples, “E” denotes an example embodiment of the present invention and “CE” denotes a counter-example.

[0345] Raw Materials

[0346] K2CO3 (potassium carbonate), obtained from Armand products

[0347] BP (4,4’-biphenol), obtained from Sigma-Aldrich, U.S.A.

[0348] DCDPS (4,4’-dichlorodiphenyl sulfone), obtained from Syensqo Speciality Polymers

[0349] ISOSO (isosorbide) obtained from Roquette Freres (France)

[0350] Sulfolane, obtained from Chevron Phillips (US)

[0351] Methanol, obtained from Sigma-Aldrich .

[0352] Methyl chloride, obtained from Matheson

[0353] MCB (monochlorobenzene), obtained from Sigma-Aldrich

[0354] DMAc (dimethylacetamide) obtained from Sigma-Aldrich with assay >99,0%

[0355] NMP (N-methyl-2-pyrrolidone) obtained from Sigma-Aldrich with assay > 99,0%

[0356] DMF (dimethylformamide) obtained from VWR with assay =100% (RO use)

[0357] DMI (dimethyl isosorbide) obtained from Sigma Aldrich with assay >99,0%

[0358] Rhodiasolv® Polar clean obtained from Syensqo group

[0359] GLV (gamma-Valerolactone) obtained from Sigma Aldrich with assay>99,9%

[0360] Demineralized water (MilliQ)

[0361] PPSU Radel® R5000NT obtained from Syensqo Specialty Polymers

[0362] PES Veradel® 3000 MP obtained from Syensqo Specialty Polymers

[0363] PSU Udel® 3500 MB3 obtained from Syensqo Specialty Polymers- 46 - SSPU 2024 / 046

[0364] PEG 400 (polyethylene glycol 400) obtained from Sigma-Aldrich

[0365] PVP K85 (polyvinylpyrrolidone) Luvitec® K85 manufactured by BASF

[0366] PVP K10 (polyvinylpyrrolidone K10) obtained from Sigma-Aldrich

[0367] Glycerol from Sigma-Aldrich, U.S.A.

[0368] BSA (bovine serum albumin) from Sigma-Aldrich

[0369] Phosphate buffered saline P4417 from Sigma-Aldrich

[0370] IPA (isopropyl alcohol) obtained from Sigma-Aldrich

[0371] EtOH (ethyl alcohol) obtained from Sigma-Aldrich

[0372] Example 1: Synthesis of copolymers (P1)

[0373] I. Synthesis of copolymers (P1-A), (P1-B) and (P1-C) by polycondensation of DCDPS, 15 mol% ISOSO and 85 mol% BP

[0374] Three separate samples of copolymers (P1) were made according to the following Procedure 1 and labelled copolymers (P1-A), (P1-B) and (P1-C). The recurring units of these 3 copolymers (P1) consisted of recurring unit (RPI) of formula (M1) and recurring unit (R*PI) of formula (N1) with 85 mol.% of (RPI) and 15 mol.% of (R*PI).

[0375] Procedure 1: To a 1-L resin kettle equipped with an overhead stirrer, nitrogen inlet, temperature probe, and a dean-stark trap were charged 71.22g (0.3825 mol) 4,4’- biphenol, 9.86g (0.0675 mol), isosorbide, 131.16g (0.4567 mol) 4,4’- dichlorodiphneyl sulfone, 71.52g (0.5175 mol) anhydrous potassium carbonate (average particle size < 30pm), and 414.16g of anhydrous sulfolane. The reaction mixture was stirred, evacuated, and purged with vacuum / nitrogen thrice. The reaction mixture was heated to 210°C until the target Mw was achieved. The polymerization was terminated by passing gaseous methyl chloride for 30 min and approximately 1g / min flow rate. This termination endcapped the copolymer by converting the -OH end groups to -OCH3 end groups. The reaction mixture was diluted with 712.7g MCB and 60.99g of sulfolane. The diluted reaction mixture was pressure-filtered through a 2.7pm glass-fiber filter pad to remove the salts. The filtered polymer solution was coagulated in 5x methanol using a Waring high-speed blender. The resulting coagulated copolymer was washed six times with methanol and finally dried in a vacuum oven overnight at 105°C.

[0376] II. Synthesis of copolymer (P1-D) by polycondensation of DCDPS, 30 mol% ISOSO and 70 mol% BP

[0377] One further sample of copolymer (P1) was made according to the following Procedure 2 and labelled copolymer (PI-D).The recurring units of this copolymer (P1-D) consisted of recurring unit (RPI) of formula (M1) and recurring unit (R*PI) of formula (N1) with 70 mol.% of (RPI) and 30 mol.% of (R*PI).

[0378] Procedure 2: To a similar setup as in Procedure 1 described above, 58.66g (0.3150 mol) 4,4’-biphenol, 19.73g (0.1350 mol) isosorbide, 131.16g (0.4567 mol) 4,4’-- 47 - SSPU 2024 / 046dichlorodiphneyl sulfone, 80.85g (0.585 mol) anhydrous potassium carbonate (average particle size < 30pm), and 407.83g of anhydrous sulfolane were charged to the 1-L resin kettle. The reaction mixture was stirred, evacuated, and purged with vacuum / nitrogen thrice, and was heated to 210°C until the target Mw was achieved. Once the target Mw was achieved, the reaction mixture was diluted with 761.88 g NMP. The diluted reaction mixture was filtered, coagulated, washed, and dried similarly to the description of Procedure 1. Contrary to the Procedure 1 , there was no termination of this copolymer with methyl chloride.

[0379] III. Synthesis of copolymer (P1-E) by polycondensation of DCDPS, 15 mol% ISOSO and 85 mol% BP

[0380] One further sample of copolymer (P1) was made according to the following Procedure 3 and labelled copolymer (PI-E).The recurring units of this copolymer (P1-E) consisted of recurring unit (RPI) of formula (M1) and recurring unit (R*PI) of formula (N1) with 85 mol.% of (RPI) and 15 mol.% of (R*PI).

[0381] Procedure 3: To a 2-gallon reactor with a similar overhead setup as described in Procedure 1 were charged 498.57g (2.678 mol) 4,4’-biphenol, 69.05g (0.473 mol) isosorbide, 918.13g (3.197 mol) 4,4’-dichlorodiphneyl sulfone, 500.65g (3.623 mol) anhydrous potassium carbonate (average particle size < 30pm), and 2899.1g of anhydrous sulfolane. The reaction mixture was polymerized and terminated similar to Procedure 1. The reaction mixture was diluted with 2772g DMAc. The diluted reaction mixture was pressure-filtered through a 1pm filter media to remove salts. The filtered polymer solution was divided into droplets which fell into a stirred precipitation bath containing 15x methanol using a prilling tower in order to form solid polymeric beads. The resulting coagulated polymeric beads were washed ten times with methanol and dried in a vacuum oven for 24 hours at 120°C.

[0382] IV. Synthesis of copolymer (P1-F) by polycondensation of DCDPS, 30 mol% ISOSO and 70 mol% BP

[0383] One additional sample of copolymer (P1) was made according to the following Procedure 4 and labelled copolymer (PI-F).The recurring units of this copolymer (P1-F) consisted of recurring unit (RPI) of formula (M1) and recurring unit (R*PI) of formula (N1) with 70 mol.% of (RPI) and 30 mol.% of (R*PI).

[0384] Procedure 4: To a similar 2-gallon reactor setup described in Procedure 3 were charged 410.62g (2.205 mol) 4,4’-biphenol, 138.11g (0.945 mol) isosorbide, 918.12g (3.197 mol) 4,4’-dichlorodiphneyl sulfone, 565.95g (4.095 mol) anhydrous potassium carbonate (average particle size < 30pm), and 2854.81g of anhydrous sulfolane. The reaction mixture was polymerized terminated, diluted, coagulated (prilled) to form solid polymeric beads which are washed and dried similarly to the description of Procedure 3.- 48 - SSPU 2024 / 046

[0385] Example 2: Characterization of copolymers (P1-A) to (P1-E)

[0386] The Mw, Mn, PDI measured by a GPC Method (Sulfones method), solution viscosity and glass transition temperature Tg measured by DSC of the 6 copolymers (P1-A) to (P1-E) are provided in TABLE 1.

[0387] Test methods

[0388] GPC Method for measuring Molecular weight (Mn, Mw) (“sulfone method”)

[0389] The molecular weights of polyarylethersulfone polymers were measured by gel permeation chromatography (GPC), using methylene chloride as a mobile phase. Two 5p mixed D columns (part # PL1110-6504) with a guard column (part # PL1110- 1120) from Agilent Technologies were used for separation. An ultraviolet detector set to 254 nm was used to obtain the chromatogram. A flow rate of 1.5 ml / min and injection volume of 15 pL of a 0.4 w / v% solution in mobile phase was selected. Calibration was performed with 10 narrow molecular weight polystyrene standards (peak molecular weight range: 371 ,000 to 580 g / mol). The number average molecular weight (Mn), the weight average molecular weight (Mw), and the polydispersity index (PDI= Mw / Mn) were reported.

[0390] Differential Scanning Calorimetry (DSC)

[0391] DSC was used to determine glass transition temperatures (Tg) and melting points (Tm)-if present. DSC experiments were carried out using a TA Instrument Discovery DSC 250 per ASTM D3418-21. DSC curves were recorded by heating, cooling, reheating, and then re-cooling the sample between 25°C and 320°C at a heating and cooling rate of 20°C / min. All DSC measurements were taken under a nitrogen purge. The reported Tg values (and if any, Tm values) were provided using the second heat curve unless otherwise noted.

[0392] Solution viscosity analysis for DMAc solutions

[0393] For rheological analysis, a solution in DMAc of each copolymer sample (P1 -A) to (P 1 - E) were prepared by adding 25 parts by weight of copolymer to 75 parts by weight of DMAc and stirring with a mechanical anchor at 40°C temperature.

[0394] The solution viscosity measurements for each 25% w / w solution in DMAc were carried out using an Anton Parr MCR72 rotational rheometer. The test was performed at a shear rate of 30 s“1and a temperature of 40°C, with the sample held under these conditions for 15 minutes. The reported viscosity values in Table 1 were obtained from the steady-state region of the measurement curve unless otherwise noted.

[0395] The viscosity value of copolymers (P1) solutions (25 wt% in DMAc at 40°C) trended with the Mw. That is to say, when the Mw increased, so did the solution viscosity.

[0396] The solution viscosities of commercial PES and PSU polymers were also measured and compared to those of the copolymers. Comparison with PPSU could not be carried out because PPSU was not soluble in DMAc.- 49 - SSPU 2024 / 046

[0397] The copolymer samples (P1-C), (P1-E) and (P1-F) with 54-55 KDa had similar solution viscosities than the reference solutions of PES and PSU having higher Mw values (65- 75 KDa).

[0398] On the other end, the copolymer samples (P1-A) and (P1-D) having similar Mw (71 , 75) than the referenced PES and PSU had much higher solution viscosities.

[0399] The DMAc dope solution containing 20 wt% copolymer P1-F (having 29 mol% isosorbide derived units) had a lower viscosity solution compared to the DMF solution containing 16 wt% P1-E (having 14 mol% isosorbide derived units). For these DMAc dope solutions, the trend for solution viscosity (PSU and PES providing the lowest viscosity) was as follows:P1-E > P1-F > PSU > PES

[0400] Solution viscosity analysis for DMF solutions

[0401] The solution viscosity measurements at 40°C for 16% w / w solutions in DMF for copolymers (P1-E), (P1-F) and PSU were carried out in the same manner. The solutions preparation and solution viscosity results are reported in Section 9.1 and reported in Table 16.

[0402] For the DMF dope solutions, the trend for solution viscosity (P1 -F providing the lowest viscosity) was as follows:PSU > P1-E > P1-F

[0403] Powder characterization (isosorbide) by1H-NMR

[0404] About 30 mg powder of each copolymer sample (P1-A) to (P1-F) was dissolved in 700pL 1 ,1 ,2,2-Tetrachloroethane-d2 (TCE-d2) at ~25 °C.A High-Resolution Liquid NMR characterization has been accomplished by using a Bruker400 MHz Ultrashield NMR equipped with a 5-mm PA BBO 400S1 BBF-H-D-05 Z probe and a Z-gradient type coil.

[0405] The isosorbide content in the copolymer samples (P1-A) to (P1-F) measured by NMR are reported in TABLE 1.

[0406] TABLE 1>- 50 - SSPU 2024 / 046

[0407] The recurring units of the copolymers (P1-A) to (P1-F) consisted of the recurring unit (R*PI) of formula (N1) derived from condensation of ISOSO and DCDPS and the recurring unit (RPI) of formula (M1) derived from condensation of BP and DCDPS, with expected R*PI):(RPI) molar ratio of 15:85 or 30:70 and actual molar ratios of from 13:87 to 29:71.

[0408] Example 3: Solubility study

[0409] For this study, a solution for each copolymer selected from (P 1 -A) to (P1 -F) was prepared by adding the 2 g of copolymer (P1) in 8 g of solvent and stirred with a magnetic stirrer at a temperature of 65°C overnight. The solution was cooled down while stirring until reaching 20°C. Similar solutions were made from commercial sulfone polymers (PES, PSU, PPSU) for benchmarking.

[0410] Solubility in various solvents: NMP, DMAc, DMF, DMI, GVL, aRhodiaSolv® Polar Clean was examined. Visual qualitative inspections are reported in TABLE 2.

[0411] It was observed that the copolymer samples (P1-A) to (P1-F) whose recurring unit (R*PI) of formula (N1) is derived from ISOSO and DCDPS and having a main recurring unit (RPI) of formula (M1) derived from BP and DCDPS were soluble in DMAc, DMF, DMI (dimethyl isosorbide), while the PPSU having a sole recurring unit of formula (M1) derived from BP and DCDPS was not.

[0412] TABLE 2. Polymers solubility observed at 20°CLegend in Table 2:S= solution was clear and homogeneous at 20°C for 3 daysNS= solution was heterogeneous at 20°C

[0413] The copolymer sample (P1-F) containing 29 mol% recurring unit (R*PI) of formula (N1) derived from ISOSO and DCDPS was soluble in RhodiaSolv® Polar Clean, while the- 51 - SSPU 2024 / 046copolymer sample (P1-E) containing a lower amount (14 mol%) of recurring unit (R*PI) of formula (N1) derived from ISOSO and DCDPS was not.

[0414] Example 4: Turbidimetric analysis

[0415] A turbidimetric analysis was carried out to verify the copolymer (P1) solution appearance and stability.

[0416] A turbidimetric assay can be used to quantify turbidity due to solid particles dispersed in a polymeric solution by using a light source. The level of transmitted light reflects the amount of particles in the solution. If no particles are present, little or no light is absorbed. As the concentration of particles increases, the light transmission decreases accordingly and the turbidimetric value (unit NTU) increases.

[0417] Turbidimeter analysis of the above-described polymeric blends in DMAc were carried out to confirm the qualitative inspection by using a Hach-TU5200 instrument and Pk / 2 vials with stopper. 15 g of solution was placed in a vial while being careful to avoid bubble air formation. If any air bubble appeared, the solution was kept at rest in the vials overnight. Before starting the turbidimeter analysis, the following standard solutions were used to calibration: 10 NTU, 20NTU, 600 NTU.

[0418] The stability for solutions of 20 wt% copolymer (P1-E) and (P1-F) in 80 wt.% NMP (preparation described in Example 3) and for comparative solutions of 20 wt.% PES, PSU and PPSU in NMP was examined by measuring the turbidity at 40°C at 0, 6 and 22 days. The turbidly values of these solutions in NMP are reported in TABLE 3.

[0419] TABLE 3: Ageing test for NMP solutions>

[0420] The stability for solutions of 20 wt.% copolymer sample (P1-E) and (P1-F) in 80 wt.% DMAc (preparation described in Example 3) and for comparative solutions of 20 wt.% PES and PSU PPSU in DMAc was examined by measuring the turbidity at 40°C at 5, 9 and 21 days. The turbidly values of these solutions in DMAc are reported in TABLE 4.

[0421] All the turbidimetric results showed that the solutions of the copolymers (P1-E) and (P1-F) in NMP and DMAc stayed clear.

[0422] The ageing test confirmed that the solutions of copolymers (P1 -E) and (P1 -F) in DMAc and NMP were stable for 22 days at 40°C.- 52 - SSPU 2024 / 046

[0423] TABLE 4: Ageing test for DMAc solutions>

[0424] An ageing test for a PPSU solution in DMAc was not included in comparative example because PPSU was not very soluble in DMAc. As shown in Example 5 below, the turbidity of a 20 wt% PPSU solution in DMAc has an initial turbidity of 24 NTU at 20°C which quickly increased to 312 NTU at 20°C at 3 hours.

[0425] Example 5: Compatibilization of PPSU in blend with copolymer (P1)

[0426] Solubility testing - visual inspection

[0427] Polymer blends in solution were prepared as follows.

[0428] For SOL 50wt% = 1g of PPSU and 1 g of a copolymer (P1) sample were added to 8 g of DMAc.

[0429] For SOL 30wt%, 1.4g of PPSU and 0.6 g of a copolymer (P1) sample were added to 8 g of DMAc.

[0430] For SOL 20wt%, 1.6g of PPSU and 0.4 g of a copolymer (P1) sample were added to 8 g of DMAc.

[0431] Each mixture with PPSU was stirred with a magnetic stirrer at a temperature of 65°C overnight and cooled down while stirring, until a temperature of 20°C was reached.

[0432] The visual inspection for solubility is reported in TABLE 5.

[0433] Turbidity Test

[0434] A turbidimetric analysis (see turbidity method in Example 4) was carried out to verify the compatibility of PPSU and copolymer (P1) in DMAc solution. The turbidly results of these solutions in DMAc are reported in TABLE 6.

[0435] TABLE 5. PSSU compatibility with copolymer (P1)Legend:- 53 - SSPU 2024 / 046 S= solution was clear and homogeneous at 20°C for at least 6 hours by qualitative inspectionNS= solution was heterogeneous at 20°C by qualitative inspection

[0436] All the turbidimetric results showed that the DMAc solutions were clear, except for the pure PPSU solution and for the blend of 80 wt% PPSU+20 wt% copolymer (P1-E) which after 3 hours started to form instable solutions (NTU values »200).

[0437] TABLE 6

[0438] Example 6: Hydrophilicity of copolymer (P1)

[0439] A ternary phase diagram shows the water tolerance of polymer in a certain solvent and temperature. The diagram is widely used to compare / understand the cloudy point, the precipitation propensity and the hydrophilicity character, see for example Kim et al, “Liquid-Liquid Phase Separation in Polys ulfone / Solvent / Water Systems”. Applied Polymer Science vol. 65 (1997) p. 2643-2653, and Lau et al, “Phase separation in polysulfone / solvent / water and polyethersulfone / solvent / water systems”. Journal of Membrane Science, vol. 59 (1991) p. 219.

[0440] Therefore the ternary phase diagram polymer / water / NMP was used to investigate the hydrophilicity of the copolymers (P1) in comparison with referenced commercial PPSU, PES and PSU polymers.

[0441] The cloud point curves were determined by a titration method at various polymer concentration at a temperature of 20 °C. A flask with a stopper was filled with the appropriate amount of water and solvent (NMP) and after mixing the appropriate amount of polymer sample was added. The proportion of each component is provided in Table 7. The polymer dissolution was accomplished by using a magnetic stirring system and the flask was kept at 60°C in an oil bath until dissolution. At the end of dissolution, the solution while still being stirred was cooled down to 20°C.

[0442] A visual inspection was noted after one night of rest. This procedure was repeated at several water / NMP wt% for each polymer concentration set (5wt%;15wt%; 20wt%) until the cloud point was observed at 20°C. This procedure was adopted for- 54 - SSPU 2024 / 046experimental samples and for reference commercial sulfone polymers (PES, PSU, PPSU).

[0443] The results for the ternary polymer / water / NMP phase diagrams are shown in Table 7 and illustrated in FIG. 1 with copolymers (P1-E) and (P1-F) in comparison with PPSU, PSU, and PES.

[0444] The hydrophilicity of the copolymers (P1-E) and (P1-F) was in between that of PES and PSU.

[0445] The copolymer (P1-F) having about 29 mol% isosorbide-derived recurring unit, was more hydrophilic that the copolymer (P1-E) having about 14 mol% isosorbide-derived recurring unit.

[0446] The resulting polymer / water / NMP ternary phase diagram at 20°C in FIG. 1 demonstrated that:- there was a higher hydrophilicity of copolymer (P1) compared to commercial PPSU and PSU polymers; and- there was an increase in hydrophilicity when increasing the isosorbide mol % in the copolymer (P1).

[0447] TABLE 7 : Composition of polymer / water / NMP solution at the cloud point.- 55 - SSPU 2024 / 046

[0448] Thus the ternary diagram phase provided the following trend of water tolerance (hydrophilicity), PES being the most hydrophilic polymer and PPSU being the least hydrophilic polymer :PES > copolymer (P1-F) > copolymer (P1-E) > PSU > PPSU

[0449] Example 7: Dense films

[0450] Before use, any polymer sample was thermally treated at 120°C for 4 hours under vacuum to remove eventual content moisture.

[0451] 7.1 Solution preparation for making dense film

[0452] Solutions for film manufacturing were prepared by adding the appropriate amount of polymer sample in NMP and stirring with a mechanical anchor stirrer at a temperature of 60°C to achieve a casting solution quantity of 30 grams. After total dissolution was reached, the solution was rested for one night at 40°C to remove any eventual air bubbles, such a temperature providing a transparent homogeneous solution without the presence of any phase separation.

[0453] For the film casting solution ”S1-x50” containing a blend of polymers, 10 g of PPSU and 10 g of copolymer (P1-x) sample were mixed with 80 g of NMP to yield a 50 wt% copolymer (P1) relative to combined weights of PPSU and copolymer (P1-x), wheren ‘x’ represents A to F.

[0454] The film casting solution compositions in NMP are reported in Table 8. In all cases, the film casting solution composition had a total polymer content of 20% w / w in NMP.

[0455] The solution transparency and stability of these NMP solutions were verified by turbidity measurement as shown in Example 4.

[0456] Dense films were prepared from these NMP solutions and compared to reference films made with PES, PSU, and PPSU in the same manner except that no copolymer (P1) was used in the film casting solution.

[0457] TABLE 8 . Film casting solution composition in NMP- 56 - SSPU 2024 / 046

[0458] 7.2 Preparation of dense film

[0459] A4 size films were prepared by casting a film casting solutions (20 wt% in NMP) kept at 40°C, over a suitable smooth glass support by means of an automatized casting knife (250 micrometer). The amount of the casting solution used for dense film preparation was about 20 grams. The film formation was accomplished by solvent evaporation method by thermal treating the film at 140°C for 15 minutes, then 160°C for 30 minutes and then 200°C for 3 hour under vacuum. The formed film was then cooled down and detached from glass support by submerging in a box filled with demineralized water. The film was washed several times in pure water and then dried and room temperature.

[0460] 7.3 Captive air bubble (CAB) contact angle measurement on polymeric dense film

[0461] Contact angles were measured by the Captive Air Bubble (CAB) method. This method measures the contact angle of an air bubble at a surface of a sample immersed in a liquid, in this case water and, as the sample is already wet, swelling and absorption are suppressed.

[0462] CAB measurements were carried out at room temperature, using an adapted environment controlled chamber filled with deionized water (DI water). The sample rolled on support is in contact with water (bottom surface hydrated). A J-shaped syringe is used to deliver air bubble drop onto the wet sample surface.

[0463] The drop image was stored by a video camera and an image analysis system (software) calculated the contact angle (0) from the shape of the drop. For each sample the contact angles values were obtained as an average of at least 5 drops deposed and measured in the air at room temperature. Contact Angle measurements were performed on an optical tensiometer (DSA100 provided by BIOLINKRUSS) equipped with a high quality monochromatic cold LED (6) and a high resolution (1984x1264) digital camera. Image acquisition parameters were set at 5 Frames Per Second (FPS) and a minimum acquisition time of 60 s. The instrument was calibrated using a calibration ball (CA = 143.15°) with an accepted error of 0.03°. Each bubble image was stored digitally, and an image analysis system (software ADVANCE) calculated the contact angle (0) from the shape of the bubble.

[0464] The CAB contact angle values reported in Table 9 were the average of 5 measurements performed in the air at room temperature on the same sample.- 57 - SSPU 2024 / 046

[0465] TABLE 9

[0466] The film made from solution S1-D (containing copolymer P1-D having 29 mol% isosorbide) showed the highest CAB contact angle (117°), meaning the highest hydrophilicity.

[0467] Since the copolymer P1-D has a higher isosorbide loading compared to copolymers P1-A to P1-C, it is inferred that the higher hydrophilicity of the film made from solution S1-D is likely due to the higher content in isosorbide.

[0468] The film made from solution S1-C (copolymer P1-C) had a higher hydrophilicity compared to the films made from solutions S1-A and S1-B containing polymers with the same isosorbide mol% content (P1-A and P1-B). It is believed that this higher hydrophilicity may be due to the lower Mw of copolymer P1-C.

[0469] The CAB analysis on dense film provided the following trend of hydrophilicity, the film made from copolymer (P1-D) being the most hydrophilic film and the films made from PPSU / PES / PSU being the least hydrophilic polymer :P1-D (29mol% ISOSO )> P1-C (14mol%) > PES / PSU / PPSU

[0470] 7.4 tensile properties of polymeric dense film

[0471] Mechanical properties on dense films were assessed at room temperature (23°C) following ASTM D 638 standard procedure (type V, grip distance = 25.4 mm, initial length Lo = 21.5 mm). Each sample was tested 5 times.

[0472] Tensile properties are reported in Table 10.

[0473] The copolymers (P1) used as sole polymer or blended with PPSU do not compromise the mechanical properties in terms of stress at break and tensile modulus of the dense films.

[0474] The copolymers (P1) blended with PPSU tend to reduce the strain at break of the dense films.- 58 - SSPU 2024 / 046

[0475] TABLE 10

[0476] Example 8: Flat porous membrane intended for hemodialysis application

[0477] Before use, any polymer sample was thermally treated at 120°C for 4 hours under vacuum to remove eventual content moisture.

[0478] In this example, flat porous membranes were made from dope solutions containing DMAc, pore former(s), water and 16 wt% sulfone polymer(s), these membranes being suitable for end use application in hemodialysis.

[0479] 8.1 Solution preparation for making flat porous membrane

[0480] Dope solutions for porous membrane manufacturing were prepared by adding the appropriate amount of a copolymer (P1), water, DMAc, PVPk85 and optionally a second sulfone polymer (P2) and stirring with a mechanical anchor stirrer at 60°C for several hours. Then the dope solutions were left at rest at 40°C for a few hours to remove eventual air bubbles. Solutions were stable and clear at 20°C for at least 3 days.

[0481] Two reference solutions were made with PES and PSU in DMAc for comparison.

[0482] The composition of each dope solution was 16wt% polymer(s) + 0.5 wt% water + 4 wt% PVP K85 + 79.5 wt% DMAc, the wt% being based on total weight of the solution.

[0483] The actual amounts used to prepare the dope solutions prepared for two sets of environmental conditions are shown in Table 11 (condition 1: 25°C and humidity <25%) and Table 12 (condition 2: 25°C and humidity 70%).

[0484] 8.2 Solution viscosity measurement

[0485] Solution viscosities were analyzed with a viscometer at 40°C in a steady state mode.Rotational steady state shear measurements were performed using a Rheometric Scientific “RFS III” rheogoniometer in the concentric cylinder configuration (Couette). Flow curves were obtained with a sweep performed from the lowest attainable shear rate (0.02 s-1) to the highest defined by the maximum torque that the instrument can- 59 - SSPU 2024 / 046reach. In all cases, a quite large Newtonian range was observed. Viscosity values in the table represent the Newtonian plateau of the flow curves.

[0486] The dope solution viscosity (in cP) measured at 40°C is also reported in Tables 11 and 12.

[0487] TABLE 11. Compositions and viscosities of dope solutions prepared for environmental condition 1 (25°C, humidity <25%)

[0488] TABLE 12. Compositions and viscosities of dope solutions prepared for environmental condition 2 (25°C, humidity 70%)

[0489] 8.3 Preparation of flat porous membrane

[0490] A4 size flat sheet porous membranes were prepared by casting a dope polymeric solution (polymer(s) + DMAc + pore former) described above, over a suitable smooth glass support by means of an automatized casting knife. The applied amount of dope solution was 20 grams.

[0491] Membrane casting was performed by holding a dope solution, the casting knife and the support at the same casting temperature of 30°C using a knife gap set to 250 pm,. After casting, polymeric membranes were immediately immersed in a coagulation bath consisting of a mixture 20:80 (w:w) DMAc / H2O at 25°C for 5 minutes in order to induce phase inversion.

[0492] In all cases, after the step of coagulation, the membranes were submerged in a demineralized water bath at 20°C for 5 minutes. The resulting membranes were- 60 - SSPU 2024 / 046washed several times in demineralized water during the following days to remove residual traces of solvent. The flat porous membranes were stored (wet) in water.

[0493] 8.4 Thickness measurement on wet membrane

[0494] Thickness was measured on wet membranes by using ABSOLUTE Digimatic Thickness Gauges provided by Mitutoyo. The thickness of each flat membrane represented an average of at least 5 measures on different positions.

[0495] The values for the membrane wet thickness (in microns) are provided in Tables 13 and 14 for conditions 1 and 2, respectively.

[0496] 8.5 Permeability measurements on flat membrane

[0497] Water flux (J) through each membrane at given pressure, is defined as the volume which permeates per unit area and per unit time. The flux is calculated with the following equation [1]:A fit Equation [1],wherein:- V (in L) is the volume of permeate,- A (in m2) is the membrane area, and- At (in h) is the operation time.

[0498] Water flux measurements were conducted at room temperature using a dead-end configuration under a constant nitrogen pressure of 1 bar using pure demineralized (MilliQ) water by using Stainless Steel Pressure Filter Holders from Millipore.Membrane discs with an effective area of 11.3 cm2were cut from the membrane sheets (stored in water) and placed on a metal plate. The analysis was carried out by using the wet membranes in water. The permeation rate was evaluated for 30 minutes during each test carried out at 1 bar by gravimetric method. The reported flux was obtained by collecting data measured from the 27thto the 30thminute of each test. For each membrane, the reported flux was the average of at least 3 different discs. The results for the permeate water flux (PWP) in L / m2 / h measured at 1 bar are provided in Tables 13 and 14 for conditions 1 and 2, respectively.

[0499] 8.6 Rejection to BSA for flat porous membrane

[0500] A dead-end stirred cell filtration system was designed to characterize the filtration performance of membranes. The system consisted of a 180-ml filtration cell (model 8010, Amicon, W.R. Grace, Beverly, MA). All filtration experiments were conducted with a feed of 0.13 g / L Bovine Serum Albumin (BSA) in phosphate buffered saline (PBS) at pH 7.4 at a constant driven pressure of 1 bar (by N2 gas line) and a stirring rate of 200 rpm at room temperature. The permeate flux was calculated using Equation [1] provided in section 8.5 by measuring the weight of permeate versus time considering a membrane sample area equal to 26.41 cm2.- 61 - SSPU 2024 / 046

[0501] At the end of the rejection test (after 22 minutes of test), 2 mL of permeate sample was collected to determine the COD (chemical oxygen demand).

[0502] The COD analysis was carried out using an oven HT 200 S (15 minutes at 170°C), spectrophotometer DR 3900 VIS from Hach, LCK 314 and LCK 514 cuvettes.

[0503] The BSA rejection ratio (R%) was calculated by the following equation [2]:R%= 100 ( Cf - Cp ) / Cf Equation [2],where, Cp and Cf are the BSA concentration in permeate and in feed in mg / L, respectively.

[0504] The results for the BSA R% obtained after 22.5 minutes are provided in Tables 13 and 14 for conditions 1 and 2, respectively.

[0505] The PSU flat porous membranes CE4 and CE10 had the highest PWP most likely because the pore sizes in these membranes were bigger (according to lower rejection) compared to the pore sizes of the flat porous membranes E1-E3 & E6-E9 made from copolymer (P1) sample.

[0506] TABLE 13 : Characteristics of porous membranes made from DMAc solutions containing 16 wt% polymer(s) under condition 1 (25°C, <25% humidity)<Wet thickness is an average of 5 point for each portion tested(b>PWP data is an average of at least 4 tests of each membrane(c)BSA Rejection was run in a single test

[0507] TABLE 14 : Characteristics of porous membranes made from DMAc solutions containing 16 wt% polymer(s) under condition 2 (25°C, 70% humidity)<>- 62 - SSPU 2024 / 046Wet thickness is the average of 5 point for each portion tested<b)PWP data is an average of at least 4 tests of each membrane(c>BSA Rejection was run in a single test

[0508] 8.7 Gravimetric porosity on porous flat membrane

[0509] Gravimetric porosity of a porous membrane was defined as the volume of the pores divided by the total volume of the membrane. Membrane porosity (8) was determined according to the gravimetric method detailed below.

[0510] Perfectly dry membrane pieces were weighed and impregnated in isopropyl alcohol (IPA) for 24h. After this time, the excess of the liquid was removed with tissue paper, and membrane weight was measured again. The porosities e were measured using IPA (isopropyl alcohol) as wetting fluid according to the procedure described in Appendix of the article by Smolders & Franken, “Terminology for Membrane Distillation”, Desalination, vol. 72 (1989) pp. 249-262.(Wet — Dry)Pliquid£(%) xlOO(Wet — Dry) DryPliquid Ppolymerwhere ‘Wet’ is the weight of the wetted membrane, ‘Dry’ is the weight of dry membrane, Ppoiymer is the density of PPSU (1.29 g / cm3) and pliquid is the density of IPA (0.78 g / cm3).

[0511] The gravimetric porosity of the porous membrane E7 (made from P1-F) was 85.3% (an average based on 3 separate measures).

[0512] 8.8 Scanning Electronic Microscope (SEM) analysis of porous flat membranes

[0513] Microscopic observation of the membrane surfaces and cross-section were performed by using a scanning electron microscope (SEM) Hitachi, TM400 Plus II at an accelerating voltage of 10kV. To realize the cross-section samples, the membranes wet in IPA were freeze-fractured in liquid nitrogen instead the surfaces after drying from IPA, were directly placed on the holder. All surfaces and cross-section were coated with Au before use.

[0514] Cross-section SEM images in Fig. 2-9 were obtained with a magnification of 400x and 5000x on cross sections of the membrane samples.

[0515] FIG. 2 and 3 represent SEM cross-section images with a magnification of 400x and 5000x of porous membranes E2 and E3 according to the invention obtained under condition 1 (25°C, <25% humidity).

[0516] FIG. 4 and 5 represent SEM images with a magnification of 400x and 5000x of porous membranes CE4 (PSU) and CE5 (PES) obtained under condition 1 (25°C, <25% humidity)- 63 - SSPU 2024 / 046

[0517] Some relevant differences were observed on the down face of membranes made from copolymers under condition 1 (25°C, <25% humidity). However, the SEM crosssection images explained the values obtained for water flux data (PWP) and BSA Rejection (R%) reported in Tables 13 and 14.

[0518] The SEM cross-section images (FIG. 2) of the porous membrane E2 made from the dope solution D2 containing 16 wt% copolymer P1-B showed a spongy structure with some macrovoids.

[0519] The SEM cross-section images (FIG. 3) of the porous membrane E3 made from the dope solution D3 containing 16 wt% copolymer P1-D showed the smallest pore and no macrovoids presence, and consequently had the lowest PWP value and the highest BSA rejection

[0520] The SEM cross-section images (FIG. 4 and 5) of the comparative PSU and PES porous membranes CE4 and CE5 showed a finger like structure with macrovoids, causing a higher water flux (PWP) but a lower BSA rejection compared to what was observed with the membranes E2-E3 according to the invention obtained with copolymers (P1) under same condition 1 (25°C, <25% humidity).

[0521] FIG. 6 and 7 represent SEM cross-section images with a magnification of 400x and 5000x of porous membranes E6 and E7 according to the invention obtained with copolymers (P1-E) and (P1-F), respectively, under condition 2 (25°C, 70% humidity).

[0522] FIG. 8 and 9 represent SEM cross-section images with a magnification of 400x and 5000x of comparative porous membranes CE10 (PSU) and CE11 (PES) obtained under condition 2 (25°C, 70% humidity).

[0523] FIG. 10 represent a SEM cross-section image with a magnification of 400x of porous membrane E8 according to the invention obtained from a blend of PPSU and copolymer (P1-E) under condition 2 (25°C, 70% humidity).

[0524] As observed in these FIG. 6-10, asymmetric membranes were successfully produced.In the SEM images of cross-sections (of magnification 400x), all membranes showed a sponge structure with macrovoids probably due to the higher humidity environmental condition (70% humidity).

[0525] 8.9 tensile properties of porous flat membranes

[0526] Mechanical properties on porous flat membranes were assessed at room temperature (23°C) following ASTM D 638 standard procedure (type V, grip distance = 25.4 mm, initial length Lo = 21.5 mm). Each sample was tested 5 times.

[0527] Tensile properties are reported in Table 15.

[0528] The tensile properties of flat porous membranes made from a copolymer (P1) were similar to the tensile properties of a flat porous membrane made from PES under same condition 1 (25°C, <25% humidity).- 64 - SSPU 2024 / 046

[0529] TABLE 15 : Tensile properties of porous flat membranes (made under condition 1)

[0530] Example 9: Flat porous membrane intended for reverse osmosis (RO) applications

[0531] Before use, any polymer sample was thermally treated at 120°C for 4 hours under vacuum to remove eventual content moisture.

[0532] In this example, flat porous membranes were made from dope solutions containing 16 wt% sulfone polymer(s) + 84 wt% DMF, these membranes being suitable for hemodialysis applications.

[0533] 9.1 Solution preparation for making flat porous membrane

[0534] Dope solutions for porous membrane manufacturing were prepared by adding the appropriate amount of a copolymer (P1) and DMF and stirring with a mechanical anchor stirrer at 60°C for several hours. Then the dope solutions were left to rest at 40°C for a few hours to remove eventual air bubbles. Solutions were stable and clear at 20°C for at least 3 days.

[0535] As shown in Example 3, the copolymers (P1) were soluble in DMF, but PPSU was not.Thus no comparative PPSU dope solution could be made in this example. Since PSU is the sulfone polymer typically used in RO membrane, a reference dope solution was made with PSU in DMF for comparison purposes.

[0536] The composition of each dope solution was 16wt% polymer in 84 wt% DMF, the wt% being based on total weight of the dope solution.

[0537] The actual amounts used to prepare the dope solutions (intended for RO end use) under a specific environmental condition 3 (21.3°C and humidity 65%) are shown in Table 16.

[0538] 9.2 Solution viscosity

[0539] The same method as described in section 8.2 was used to measure the solution viscosity of the dope solutions prepared in section 9.1. The dope solution viscosity (in cP) measured at 40°C is reported in Table 16.

[0540] Similarly to what was observed with DMAc dope solutions, the DMF dope solution containing 16 wt% copolymer P1-F (having 29 mol% isosorbide derived units) had a lower viscosity solution compared to the DMF solution containing 16 wt% P1-E (having 14 mol% isosorbide derived units).

[0541] For the DMF dope solutions, the trend for solution viscosity (P1-F providing the lowest viscosity) was as follows:- 65 - SSPU 2024 / 046PSU > P1-E > P1-F

[0542] TABLE 16 : Dope solutions composition intended for RO - condition 3: 21.3°C and 65% humidity

[0543] 9.3 Preparation of flat porous membrane (intended for RO end-use)

[0544] A4 size flat sheet porous membranes suitable for RO were prepared in the same manner as described in section 8.3, except that the dope solutions composition (16 wt% polymer in DMF) were used for casting these porous membranes, and the casting conditions were as follows: the casting temperature was 25°C; the knife gap was set to 200 pm; and the coagulation bath was at 20°C and consisted of a mixture DMF / water using a weight ratio: 4wt% DM F / 96wt% water.

[0545] In all cases, after the step of coagulation, the membranes were submerged in a demineralized water bath at 20°C for 5 minutes. The resulting membranes were washed several times in demineralized water during the following days to remove residual traces of solvent. The flat porous membranes were stored (wet) in water.

[0546] 9.4 Thickness measurement on wet membrane

[0547] Thickness was measured on wet membranes prepared in section 9.3 using the same method described in section 8.4. The thickness of each flat membrane was referred to the average of 5 measures. The results for the membrane wet thickness (in microns) are provided in Table 17.

[0548] 9.5 Permeability measurements on flat membrane (intended for RO end use)

[0549] Water flux measurements were carried out by using the wet membranes stored in water prepared in section 9.3 in the same manner as described in section 8.5. The permeation rate was evaluated for 30 minutes during each test carried out at 1 bar by gravimetric method and the equation [1] was used to calculate the flux. For each membrane, the reported flux (PWP) expressed in LMH (liters / square meter x hour) was the average obtained with 4 different discs.

[0550] The results for the permeate water flux (PWP) in L / m2 / h measured at 1 bar are provided in Table 17 for condition 3.

[0551] 9.5 Rejection to BSA for flat porous membrane (intended for RO end use)

[0552] The BSA rejection rate of the porous membranes prepared in section 9.3 was measured using the same method as described in section 8.6 with a feed of 0.13 g / L- 66 - SSPU 2024 / 046Bovine Serum Albumin (BSA) in phosphate buffered saline (PBS) at pH 7.4 at a constant driven pressure of 1 bar (by N2 gas line) and a stirring rate of 200 rpm at room temperature. The results for the BSA R% obtained after 22.5 minutes are provided in Table 17.

[0553] TABLE 17 : Characteristics of flat porous membranes (intended for RO end use) made by casting from DMF solutions containing 16 wt% polymer(s) under condition 3 (21 ,3°C, 65% humidity)(a)Wet thickness is the average of 5 point for each portion tested<b)PWP data in L / m2*h*bar is an average of 4 tests of each membrane(°) BSA Rejection was run in a single test

[0554] The PSU flat porous membranes CE14 had the highest PWP and lowest BSA rejection, most likely because the pore size in this membrane was bigger compared to the pore size of the flat porous membranes E12 and E13 made from copolymer (P1) samples.

[0555] 9.7 Gravimetric porosity on porous flat membrane (intended for RO end use)

[0556] The gravimetric porosity was carried out in the same manner as described in section 8.7.

[0557] The gravimetric porosity of the flat porous membrane E13 (made by casting a DMF dope solution containing 16 wt% copolymer P1-F) prepared in section 9.3 and characterized in Table 17 was 80.0% (an average based on 3 separate measures).

[0558] 9.8 SEM analysis of porous flat membranes (intended for RO end use)

[0559] Microscopic observation (SEM) of the membrane surfaces and cross-section were performed in the same manner as described in section 8.8. All surfaces and crosssection were coated with Au before use.

[0560] Cross-section SEM pictures in FIG. 11-13 were obtained with a magnification of 600x on cross sections of the membranes E12, E13 and CE14, respectively.

[0561] As observed in the SEM of cross section (x600) in FIG. 11-13, asymmetric membranes were successfully produced. These membranes showed a sponge structure with macrovoids probably due to the environmental condition (65% humidity).

[0562] Example 10: Hollow-fiber porous membrane intended for water filtration end uses- 67 - SSPU 2024 / 046

[0563] Before use, any polymer sample was thermally treated at 120°C for 4 hours under vacuum to remove eventual content moisture.

[0564] In this example, hollow-fiber [“HF”] porous membranes were made from dope spinning solutions in NMP, these membranes being suitable for water filtration end uses.

[0565] 10.1 Spinning solution preparation for making porous HF membrane

[0566] Dope spinning solutions for making porous HF membrane (intended for water filtration end uses) were prepared by adding an appropriate amount of polymer, PEG400, PVPk10 and solvent (NMP) in a glass bottle. The dissolution was accomplished while stirring in a Falc equipment (oil bath) thermostated at 50°C. The stirring lasted for several hours at 50°C. Then the dope solutions were left to rest at 50°C overnight to remove eventual air bubbles.

[0567] The composition for dope spinning solutions for making porous HF membrane was as follows (the wt% being based on total weight of spinning solution):- 20 wt% polymer(s)- 25 wt% PEG400- 5 wt% PVP K10- 50 wt% NMP.

[0568] The spinning solutions were labelled as follows:D15 : PES (for comparison)D16: P1-ED17: P1-ED18 : a blend of P1-F and PPSU (50w / 50w)

[0569] 10.2 Solution viscosity

[0570] The same method as described in Section 8.2 was used to measure the solution viscosity of the dope spinning solutions containing 20 wt% polymers in NMP prepared in section 10.1, except that the viscosities were measured at 30°C and 50°C. The viscosity (in cP) measured are reported in Table 18.

[0571] TABLE 18

[0572] The dope spinning solutions D16-D18 containing 20 wt% copolymer (P1) or a blend of copolymer (P1) + PPSU in NMP had a higher viscosity than the dope spinning solution D15 containing 20 wt% PES.- 68 - SSPU 2024 / 046

[0573] 10.3 Preparation of porous HF fibers

[0574] The following spinning technique was used for the dope spinning solutions D15-D17 described in Section 9.1 to make hollow fibers.

[0575] The spinning process was performed with the triple orifice spinneret. During the spinning a coagulant (nonsolvent) was pumped through the outmost orifice of the spinneret; the dope spinning solution and a bore liquid were pumped through their corresponding orifices. The bore fluid was a mixture of a mixture of water / NMP (50wt% / 50wt%), and water was used as coagulation bath. The holding tank for the spinning solution, gear pump, the spinneret, and the coagulation bath were kept at 50°C.

[0576] During spinning, the dope spinning solution was fed at a constant mass flow rate was kept constant to 4.0 g / min. The effect of bore fluid mass flow rate on membrane morphology was investigated using different bore fluid rates of 4.5; 3.3; 2.1 g / min. After 15 minutes of spinning, hollow fiber samples obtained with the 3 different bore fluid rates were collected for each spinning solution.

[0577] The various hollow fiber samples were stored in a water / glycerol mixture (85wt% / 15wt%).

[0578] 10.4 Measurement of concentricity, wet thickness, ID and OP of HF membrane.

[0579] The thickness, external diameter [“OD’] and internal diameter [“ID”] of dried hollow fibers (HF) were measured as average of 5 cross sections by optical microscopy Leica DMS300 and reported in Table 19.

[0580] The concentricity of dried HF was also measured using the following equation [4]:Concentricity(%) =100 (D minimum thickness / D maximum thickness ) [4] wherein the D minimum thickness is the smallest thickness, and the D maximum is the highest thickness measured by microscopy in a same fiber.

[0581] The concentricity reported in Table 19 is an average of at least 6 fiber analysis by microscopy.- 69 - SSPU 2024 / 046

[0582] TABLE 19

[0583] 10.5 Tensile properties of porous HF

[0584] Tensile properties were assessed at room temperature (23°C) by a technique inspired by the “Standard Test Methods for Hookup Wire Insulation” ASTM D3032-21 on porous wet hollow fibers with an initial length of 125 mm and speed of 125 mm / min. During the tests, the fibers were maintained wet. Each sample was tested 5 times. Analysis for mechanical properties was carried out by means of a ZwickRoell instrument under room condition 23°C with 50% humidity.

[0585] Tensile properties of HF samples CE15b, E16b, E17b, E18b are reported in Table 20.

[0586] TABLE 20 : Tensile properties of hollow fibers

[0587] The tensile properties of HF (E16b, E17b) made from a copolymer (P1) showed comparable tensile modules, but a lower strain at break and lower stress at break compared to PES-based HF (CE15b).

[0588] The tensile properties of HF (E18b) made from a blend of PPSU and a copolymer (P1) showed lower tensile properties: lower tensile modules, lower strain at break and lower stress at break compared to PES-based HF (CE15b).

[0589] 10.6 Preparation of porous HF membrane- 70 - SSPU 2024 / 046

[0590] Hollow fiber samples produced in Section 10.3 were dried from water / glycerol mixture (85wt% / 15wt%) and properly cut for the assembly of a HF module containing 3 cylindrical hollow fibers (obtained with the same dope solution and same rates of dope solution rate and bore fluid). The 3 HF were fixed to the module with an epoxy resin, and the resulting length of the HF in the HF module was about 16-17 cm. Before use, the glycerol was removed by washing each HF membrane module first with an ethanol / water mixture (25wt% / 75wt%)and then with water.

[0591] The filtration performance of each HF membrane module containing 3 hollow fibers was evaluated. Before starting the filtration testing, the module was submerged in water for 1 hour.

[0592] 10.7 Permeability measurements (PWP) on HF membranes

[0593] Water flux measurements of HF membrane modules were conducted at room temperature using a circular configuration system under a constant pressure of 1.5 bars using pure MilliQ water. In order to evaluate the flux ‘J’ as shown in Equation [1], the surface area was calculated using Equation [3] as follows:Area = n x2nxlD / 2 xL Equation [3] wherein- n represents the number of the hollow fibers in the module,- L represents the length of the HF, and- ID / 2 represents the internal radius of the HF.

[0594] The water flux test was performed for 60 minutes in a continuous configuration, and the permeation rate was evaluated in the last 3 minutes of test.

[0595] The values for the permeate water flux (PWP) in L / m2 / h at a given pressure (in Bar) and for the resulting PWP in L / m2 / h / bar for the HF membranes CE15b, E16b, E17b, E18b made using the same bore fluid flow rate of 3.3 g / min are provided in Table 21.

[0596] 10.8 Rejection to BSA for porous HF membrane

[0597] For BSA rejection, all filtration experiments were conducted in each HF membrane module with a feed of 0.13 g / L BSA in phosphate buffered saline (PBS) at pH 7.4 at a constant driven pressure and at room temperature.

[0598] At the end of the rejection test, a 2 mL permeate sample was collected to determine the COD (chemical oxygen demand). The permeate flux was calculated by gravimetric method versus time using the Equation [1] considering the total HF membranes area in the module, this surface area being calculated using the Equation [3]. Then the BSA rejection rate (R%) was calculated as explained in Section 8.6 using the Equation [2].

[0599] The results for the BSA rejection test (R%) obtained during a period of 22.5 minutes for the HF membranes made using the same spinning solution flow rate of 4 g / min and the same bore fluid flow rate of 3.3 g / min are provided in Table 21.- 71 - SSPU 2024 / 046

[0600] TABLE 21PWP and BSA data were obtained from one test run in recycle mode

[0603] The HF membranes ME16b, ME17b whose HFs were made from spinning solutions D16 and D17 containing a copolymer (P1) and the HF membrane ME18b whose HFs were made from spinning solution D18 containing PPSU + a copolymer (P1) showed higher PWP performance compared to the PES reference HF membrane CME15b.

[0604] Both HF membranes ME16b, ME17b whose HFs were made from spinning solutions D16 and D17 containing a copolymer (P1) showed increased BSA rejection performance compared to the PES reference HF membrane CME15b.

[0605] 10.9 SEM analysis of HF membranes (intended for water filtration use)

[0606] Microscopic observation (SEM) of the HF surfaces and cross-section were performed in the same manner as described in section 8.8. All surfaces and cross-section were coated with Au before use.

[0607] Cross-section SEM pictures in FIG. 14-17 were obtained with a magnification of 60x (a), 500x (b), 2000x (c) on cross-sections of the hollow fibers CE15B, E16b, E17b, E18b, respectively.

[0608] As observed in the SEM of cross section of hollow fibers (magnitude x600) in FIG. 14- 17, asymmetric membranes were successfully produced. These membranes showed a sponge structure with macrovoids, probably due to the environmental condition (65% humidity).

[0609] Example 11: Comparative films made according to US2017 / 02400708A1

[0610] US2017 / 240708A1 [US’708] described the synthesis of a polysulfone copolymer made from DCDPS, isosorbide and biphenol in Example 10 (see

[0046] and Table 3) which had 20 mol% isosorbide-derived recurring units and 80 mol% biphenol-derived- 72 - SSPU 2024 / 046recurring units. To test the chemical resistance, films were made from a 25 wt% solution in DMAc as described in

[0054] -

[0056] of US’708.

[0611] 11.1 Preparation of films according to method described in US’708

[0612] For comparison, films were made with the copolymer samples (P1-E) and (P1-F) by utilizing the film procedure in

[0054] -

[0056] of US’708. The sole difference was that a glass support was used instead of a polypropylene support to cast the films.

[0613] A 25 wt% polymer casting solution in DMAc of each copolymer (P1-E) and (P1-F) was made according to

[0055] of US’708 - see solution compositions in Table 22.

[0614] TABLE 22. Casting solution composition used for chemical resistance

[0615] The polymer casting solution (20g) was casted over a suitable smooth glass support by means of an automatized casting knife with a knife gap set to 200 pm at the rate of 0.2 m / min, and the upper portion was exposed to air at 20° C with 66% humidity for about 2 minutes. After these 2 minutes, the glass support containing the wet casting was immersed in a methanol coagulation bath for 3 minutes in order to induce phase inversion (first solidification). The casting was then peeled off from the glass support. The peeled casting was then immersed in a deionized water coagulation bath (second solidification) and kept there for about 3 hours for complete solvent exchange. The resulting film was then dried at 80° C for 3 hours to obtain a dry film.

[0616] The comparative films made according to US’708 method from copolymers P1-E and P1-F, respectively, are identified as CE19 and CE20.

[0617] 11.2 Chemical resistance test in DMAc

[0618] The dried films (after drying at 80°C for 3 h) were cut in portions of 3 cm*3 cm.

[0619] These portions were subjected to the same chemical resistance test as described in

[0057] of US’708 and the degree of dissolution or swelling was observed.

[0620] Chemical resistance condition 1 : 20°C for 24 h (or 72h) in 500 ml DMAc

[0621] Chemical resistance condition 2: 60°C for 24 h (or 72h) in 500 ml DMAc

[0622] While Table 5 in US’708 reported than the 3x3 portions of film from US’708 Example 10 has a rating of 1 , meaning remained undissolved, the films obtained using the same film casting technique of US’708 from the copolymers (P1-E) and (P1-F) dissolved quickly and totally in the 500 ml DMAc, meaning a rating of 5 (very well dissolved) according to the rating legend underneath Table 5 of US’708. Due to the- 73 - SSPU 2024 / 046very rapid and total dissolution of the 3cmx3cm portions of films, it was not possible to evaluate the changes in weight and thickness of these portions overtime.

[0623] 11.3 Gravimetric porosity

[0624] The gravimetric porosity of films CE19 and CE20 was measured in the same manner as described in Section 8.7.

[0625] In Table 23, the gravimetric porosity (average of 3 different measurements) of films CE19 and CE20 was compared to the values obtained with porous film E7 (made from 20wt% copolymer P1-F in DMAc under condition 2 (25°C, 70% humidity)) and porous film E13 (made by casting a 16 wt% copolymer P1-F solution in DMF in section 9.3) (made from 16wt% copolymer P1-F in DMF under condition 3 (21.3°C, 65% humidity)).

[0626] The gravimetric porosities of the films CE19 and CE20 made according to the film casting technique in

[0054] -

[0056] of US’708 from the copolymers (P1-E) and (P1-F) were 69.7% and 75.5%, respectively. These values are lower than those obtained from the porous films E7 (84.5%) and E13 (80%) according to the invention obtained from the copolymer (P1-F).

[0627] TABLE 23

[0628] 11.4 Thickness measurement on wet membrane

[0629] For a proper wetting of the films made in Section 11.1 , a portion of each film C29 and CE30 was first submerged in isopropanol for 2.5 hours and then stored in demineralized water for 2 days.

[0630] Wet thickness was measured on wet membranes by using the same technique described in Section 8.4. The thickness of each flat membrane was referred to the average of at least 5 measures.

[0631] The results for the membrane wet thickness (in microns) of films CE19 and CE20 are provided in Table 24.

[0632] 11.5 Permeability measurements on films casted according to US’708

[0633] Water flux measurements were carried out by using wet films stored in water described in section 11.4.

[0634] PWP permeation flux measurements were carried out at 20°C by using Millipore steel system (test equipment is the same as described for the flat membrane PWP evaluation in section 8.5) by gravimetric method and the equation [1] was used to- 74 - SSPU 2024 / 046calculate the flux. For each film, the reported flux (PWP) expressed in LMH (liters / square meter x hour) was the average obtained with 4 different discs.

[0635] The total test time was 60 minute for each membrane. For each film, the permeation rate was evaluated for 15 minutes at 1 bar, then the next 10 minutes at 2 bars, then the next 10 minutes at 3 bars and finally the last 25 minutes at 4 bars.

[0636] For the film CE19, there was no PWP from 1 to 4 bars.

[0637] For the film CE20, there was no PWP at 1 and 2 bars, and very little PVP at 3 and 4 bars. By slope of permeation at 3 bars, the PWP was determined to be 1 LMHB ( = 3.2 LMH : 3 bars). However, the permeation flux then decreased at 4 Bars to 0.16 LMHB (= 0.62 LMH : 4 Bars) ; it is likely that the PWP decreased because compaction occurred due to the applied pressure.

[0638] The results for the permeate water flux (PWP) in L / m2h bar are provided in Table 24.

[0639] TABLE 24<>Wet thickness is the average of 5 point for each portion tested(b>PWP data is an average of at least 4 tests of each membrane

[0640] The films CE19 and CE20 of the DMAc dope solutions containing the copolymer (P1) made according to the casting method in US’708 were not porous.

[0641] 10.6 SEM analysis of films casted according to US’708

[0642] Microscopic observations (SEM) of the film cross-section were performed in the same manner as described in section 8.8. All surfaces and cross-section were coated with Au before use.

[0643] Cross-section SEM pictures in FIG. 18 and 19 were obtained with a magnification of 800x on cross sections of the films CE19 and CE20, respectively and with 2000x magnifications of the top portion (b1) and bottom portion (b2).

[0644] As observed in the SEM of cross section (x600) in FIG. 18 and 19, a cellular type structure was observed. In addition it seems that one of the two surfaces was closed or had very small pore. These SEM images thus confirmed the PWP results that these films casted according to technique in US’703 no or very little water flow and are non- porous.

[0645] The SEM images FIG. 18 and 19 of non-porous films CE19 and CE20 are in contrast with the flat porous asymmetric membranes showing a sponge structure with- 75 - SSPU 2024 / 046macrovoids - see for example FIG. 7 for flat membrane E7 and FIG. 12 for flat membrane E13.

[0646] Asymmetric membranes were successfully produced. These membranes showed a sponge structure with macrovoids, probably due to the environmental condition (65% humidity).

[0647] What is claimed is:

Claims

1.- 76 - SSPU 2024 / 046CLAIMSClaim 1. A porous membrane having a gravimetric porosity of at least 75%, or more than 75%, or at least 76%, or at least 77%, or at least 78%, and a pure water permeance (PWP) of at least 75 L / m2 / h / bar [“LMHB”], or more than 75 LMHB, or at least 76 LMHB, or at least 77 LMHB, or at least 78 LMHB, or at least 79 LMHB, or at least 80 LMHB, or at least 81 LMHB, or at least 82 LMHB, or at least 83 LMHB,said porous membrane comprising at least one aromatic sulfone copolymer (P1) [hereinafter “copolymer (P1)”],said copolymer (P1) comprising, collectively, at least 50 mol%, at least 60 mol%, at least 70 mol%, at least 75 mol%, at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 98 mol.%, or at least 99 mol.%, of sulfone recurring units (RPI) and of sulfone recurring units (R*PI), the mol% being based on the total molar amount of recurring units in the copolymer (P1),said copolymer (P1) comprising at least 35 mol. % of the recurring unit (RPI) based on the total molar amount of recurring units in the copolymer (P1),said sulfone recurring units (RPI) being represented by formula (M1):- said sulfone recurring units (R*PI) being represented by any formula selected from following formulas (N1), (N2) and / or (N3):- 77 - SSPU 2024 / 046wherein the molar ratio of the recurring units (R*PI) to the recurring units (RPI) is from 5 / 95 to 80 / 20, preferably from 10 / 90 to 70 / 30, more preferably from 10 / 90 to 65 / 35, yet more preferably from 10 / 90 to 60 / 40, still more preferably from 10 / 90 to 50 / 50, even more preferably from 10 / 90 to 40 / 60, most preferably from 10 / 90 to 30 / 70.Claim 2. The porous membrane of claim 1 , wherein said copolymer (P1) further comprises, collectively, at least 5 mol% of other sulfone recurring units (RPI’) and other sulfone recurring units (R*pT),said other sulfone recurring units (Rp ) being represented by formula (MT):- said other sulfone recurring units (R*PI’) being represented by any formula selected from following formulas (NT), (N2’) and / and (N3’):- 78 - SSPU 2024 / 046(N3’)_ wherein in formulae (MT), (N1 ’), (N2’), (N3’):each R is selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate; andeach i is an integer from 0 to 4, with the proviso that at least one i is not zero, preferably each i is 1 ;andwherein the molar ratio of the recurring units (R*PI’) to the recurring units (Rp ) is from 5 / 95 to 50 / 50, preferably from 10 / 90 to 45 / 55, more preferably from 10 / 90 to 40 / 60, yet more preferably from 10 / 90 to 35 / 65, still more preferably from 12 / 88 to 35 / 65, even more preferably from 12 / 88 to 30 / 70, most preferably from 15 / 85 to 30 / 70.Claim 3. The porous membrane of claim 2, wherein at least 99 mol.% of recurring units of said copolymer (P1) based on the total molar amount of recurring units of the copolymer (P1) are sulfone recurring units (Rpi) represented by formula (M1), sulfone recurring units (R*PI) represented by formula (N1), sulfone recurring units (Rp ) represented by formula (MT), and sulfone recurring units (R*PI’) represented by formula (NT).Claim 4. The porous membrane of claim 2 or 3, wherein in both formulas (M1 ’) and (NT), each i is 1 and their corresponding R is the same and selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate.Claim 5. The porous membrane of claim 1 , wherein at least 99 mol.% of recurring units of said copolymer (P1) based on the total molar amount of recurring units of the copolymer (P1) are sulfone recurring units (RPI) represented by formula (M1) and sulfone recurring units (R*PI) represented by formula (N1).- 79 - SSPU 2024 / 046Claim 6. The porous membrane of any one of claims 1 to 5, further comprising an aromatic sulfone polymer (P2) (hereinafter “PAES polymer (P2)”) different than the copolymer (P1),wherein the amount of the copolymer (P1) is from 20 parts by weight [“pbw”] to 90 pbw, or from 25 pbw to 80 pbw, or from 30 pbw to 70 pbw, or from 40 pbw to 60 pbw, or 50 pbw, of the copolymer (P1), said pbw being based on 100 parts ofthe combination ofthe copolymer (P1) and the PAES polymer (P2).Claim 7. The porous membrane of claim 6, wherein said PAES polymer (P2) comprises at least 80 mol.%, or at least 85 mol.%, or at least 90 mol.%, or at least 95 mol.%, or at least 98 mol.%, or at least 99 mol.%, of recurring units (RP2) represented by formulae (M2) or a combination of formulae (M2) and (M2’), based on the total number of moles of recurring units in the PAES polymer (P2),said recurring units (RP2) being preferably represented by formula (M2):T is selected from the group consisting of a single bond, -SO2-, -C(CH3)2- and any mixture therefrom, preferably selected from a single bond and / or -SO2-, more preferably being a single bond;each R’ is independently selected from the group consisting of carboxylic acid, alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), alkyl sulfonate, alkali metal phosphonate, alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary ammonium, preferably being independently selected from the group consisting of alkali metal sulfonate, alkaline earth metal sulfonate, sulfonic acid (-SO3H), and alkyl sulfonate; andeach k is independently an integer from 0 to 4, with the proviso that at least one k is not zero, preferably each k is 1.Claim 8. The porous membrane of any one of claims 1 to 7, further comprising at least one pore former (A) selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;- 80 - SSPU 2024 / 046at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”]; and any combination thereof,preferably selected from the group consisting of a PVP having a molecular weight of at least 5,000 g / mol to 360,000 g / mol, a PEG with a formula weight from 200 g / mol to 900 g / mol, and any combination thereof.Claim 9. The porous membrane of any one of claims 1 to 8, being selected from one or more hollow fibers, preferably one or more asymmetric hollow fibers, one or more flat membranes, preferably one or more asymmetric flat membranes, or a porous support or selective layer in a thin-fi Im composite membrane.Claim 10. The porous membrane of any one of claims 1 to 9, being used for hemodialysis, desalination and / or water filtration, such as reverse osmosis, ultrafiltration or nanofiltration.Claim 11. The porous membrane of any one of claims 1 to 10, being a hollow fiber membrane comprising said copolymer (P1), wherein the hollow fiber has an average thickness from 0.5 to 500 microns and is produced by spinning a dope solution, when said hollow fiber porous membrane is used for water filtration, the dope solution comprises said copolymer (P1), polyethylene glycol (PEG) of molecular weight 200-900 g / mol and polyvinylpyrrolidone (PVP) of molecular weight 5,000-360,000 g / mol in dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), orwhen said hollow fiber porous membrane is used in hemodialysis, the dope solution comprises said copolymer (P 1 ) , optionally a PPSU polymer (P2), 3 to 6 wt% of polyvinylpyrrolidone (PVP) of molecular weight 5,000-360,000 g / mol in dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), wherein the recurring unit of optional PPSU polymer (P2) is represented by the formula (M1).Claim 12. The porous membrane of any one of claims 1 to 10, being a reverse osmosis membrane comprising a porous support membrane layer formed from the copolymer (P1) which supports a thin selective layer, preferably a thin-film polyamide selective layer formed by interfacial polymerization on the support layer, the porous support membrane layer being casted from a dope solution comprising the copolymer (P1) in N,N- dimethylformamide (DMF) as solvent.Claim 13. The porous membrane of any one of claims 1 to 10, being a water filtration membrane comprising a flat sheet or hollow fiber prepared from a dope solution- 81 - SSPU 2024 / 046comprising said copolymer (P1) in polyethylene glycol (PEG) having a molecular weight of 200-900 g / mol, and polyvinylpyrrolidone (PVP) of molecular weight 5,000-360,000 g / mol in N-methylpyrrolidone (NMP).Claim 14. The porous membrane of any one of claims 1 to 13, wherein the copolymer (P1) comprises at least 10 mol.% to at most 30 mol.% of the recurring units (R*PI) of formula (N1), the mol% being based on the total molar amount of recurring units in the copolymer (P1).Claim 15. A polymeric composition to manufacture the porous membrane according to any one of claims 6 to 11 , comprising the copolymer (P1) and the PAES polymer (P2), wherein the weight ratio of the copolymer (P1) to the PAES copolymer (P2) is from 5:95 to 70:30, preferably from 10:90 to 60:40, more preferably from 15:85 to 50:50.Claim 16. The polymeric composition of claim 15, being :a powder ora polymeric solution comprising a solvent selected from the group consisting of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl isosorbide (DMI), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polar- clean), gamma-valerolactone (GLV), N,N-dimethylacetamide (DMAc), N- butylpyrrolidone (NBP), N-ethyl-2-pyrrolidone (NEP), cyrene, e-caprolactam, butyrolactone, 1 ,3-dimethyl-2-imidazolidinone, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), chlorobenzene, sulfolane, N,N-dimethyl lactamide (AMD), and any combination of two or more thereof, preferably selected from the group consisting of NMP, DMF, DMAc, DMSO, and any combination of two or more thereof;said polymeric solution comprising a combined weight of the copolymer (P1) and the PAES polymer (P2) from 10 wt% to 25 wt%, preferably from 15 wt% to 25 wt%, more preferably from 16 wt% to 23 wt%, yet more preferably from 16 wt% to 21 wt%, said wt% being based on the entire weight of the polymeric solution.Claim 17. The polymeric composition of claim 15 or 16, further comprising at least one pore former (A) selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”];at least one (poly) hydroxy I aliphatic alcohol having from 1 to 6 carbon atoms, preferably at least one glycerol compound,- 82 - SSPU 2024 / 046at least one carboxylic acid comprising at least 3 carbon atoms, preferably propionic acid, at least one polyvinyl alcohol;at least one polyvinyl acetate;cellulose acetate; andany combination thereof,wherein the amount of the one or more pore formers (A) is from 20 parts by weight (pbw) to 200 pbw, preferably from 25 pbw to 180 pbw, relative to 100 pbw of the combined amounts of the copolymer (P1) and the PAES copolymer (P2)Claim 18. The polymeric composition of any one of claims 15 to 17, wherein at least 99 mol.% of the recurring units of said copolymer (P1) based on the total molar amount of recurring units of the copolymer (P1) are sulfone recurring units (RPI) represented by formula (M1) and sulfone recurring units (R*PI) represented by formula (N1); wherein the PAES copolymer (P2) is PPSU; wherein the one or more pore former (A) is PVP and optionally one selected from the group consisting of PEG, glycerol, and propionic acid.Claim 19. A method for improving the solubility and compatibility of a PSSU polymer (P2) in a solvent, comprising mixing an aromatic sulfone copolymer (P1) with the PPSU polymer (P2) and at least one pore former (A) in the solvent to form a polymeric solution, wherein said aromatic sulfone copolymer (P1) comprises, collectively, at least 50 mol%, at least 60 mol%, at least 70 mol%, at least 75 mol%, at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 98 mol.%, or at least 99 mol.%, of sulfone recurring units (RPI) and of sulfone recurring units (R*PI), the mol% being based on the total molar amount of recurring units in the copolymer (P1),said sulfone recurring units (RPI) being represented by formula (M1):- said sulfone recurring units (R*PI) being represented by formula (N1):(N1),- 83 - SSPU 2024 / 046wherein the amount of the one or more pore formers (A) is from 20 to 200 parts, preferably from 25 to 180 parts, relative to 100 parts of the copolymer (P1) and the PPSU polymer (P2);wherein said PPSU polymer (P2) comprises at least 80 mol.%, at least 85 mol.%, at least 90 mol.%, at least 95 mol.%, at least 98 mol.%, or at least 99 mol.%, of recurring units (RP2), based on the total number of moles of recurring units in the PPSU polymer (P2), said recurring units (RP2) being represented by formulae (M1):wherein the at least one pore former (A) is selected from the group consisting of :at least one polyvinylpyrrolidone [“PVP”] preferably having a molecular weight of at least 5,000 g / mol to 360,000 g / mol;at least one polyalkylene glycol with a formula weight > 200 g / mol, preferably from 200 g / mol to 900 g / mol, preferably a polyethylene glycol [“PEG”];at least one (poly)hydroxyl aliphatic alcohol having from 1 to 6 carbon atoms, preferably at least one glycerol compound,at least one carboxylic acid comprising at least 3 carbon atoms, preferably propionic acid,at least one polyvinyl alcohol;at least one polyvinyl acetate;cellulose acetate; andany combination thereof,wherein the amount of the one or more pore formers (A) is from 20 parts by weight (pbw) to 200 pbw, preferably from 25 pbw to 180 pbw , relative to 100 pbw of the combined amounts of the copolymer (P1) and the PPSU polymer (P2);wherein the solvent is N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl isosorbide (DMI), or any combination thereof; andwherein the weight ratio of the copolymer (P1) to the PSSU copolymer (P2) in the polymeric solution is from 5:95 to 70:30, preferably from 10:90 to 60:40, more preferably from 15:85 to 50:50.Claim 20. The method of claim 19, wherein the copolymer (P1) comprises at least 10 mol.% to at most 30 mol.% of the recurring units (R*PI) of formula (N1), the mol% being based on the total molar amount of recurring units in the copolymer (P1).

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