A novel process for making PBI films starting from gel PBI membranes polymerized and cast in the PPA process wherein acid-imbibed gel PBIs are neutralized in a series of water baths and undergo controlled drying in association with a substrate material, yielding a PBI film without the use of organic solvents.

A process for the preparation of ultrafiltration and microfiltration polymeric flat sheet separation membranes is disclosed, the process comprising a unidirectional cooling step. Membranes prepared according to the process exhibit numerous advantages over ultrafiltration and microfiltration membranes prepared via conventional processes. In particular, the membranes prepared by the present process exhibit remarkable pure water flux, superior mechanical properties and increased anti-fouling characteristics. Also disclosed are particular PVDF ultrafiltration and microfiltration membranes having improved flux, mechanical and anti-fouling properties.

The present invention discloses a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof. The hollow fiber membrane comprises 30%-50% of polyvinylidene fluoride resin, 40%-60% of inorganic molecular solution in-situ pore-forming agent and 5%-20% of organic diluent. The preparation method comprises preparing the inorganic molecular solution in-situ pore-forming agent formed from organic sol, mixing the inorganic molecular solution in-situ pore-forming agent formed from the organic sol with high-molecular polymer resin and the organic diluent to obtain a material A, extruding hollow fibers through a forming mold, stretching on line by 2-3 times to obtain hollow fiber filaments, extracting the hollow fiber filaments with an organic solvent to remove all organic matters, removing inorganic matters dispersed in the hollow fiber filaments by using an acid or alkaline solution to form a porous membrane and cleaning the porous membrane, setting and performing heat treatment to obtain the polyvinylidene fluoride hollow fiber membrane.

A polysulfone-urethane copolymer is disclosed, which can be used as a membrane polymer, e.g., a matrix polymer, a pore forming agent, or both, while enhancing a membrane's blood compatibility. Methods are disclosed for forming the copolymer and incorporating the copolymer in membranes (e.g., spun hollow fibers, flat membranes) and other products.

A porous asymmetric membrane comprises a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer; and a polymer additive. A separation module can be fabricated from the porous asymmetric membrane. A method of forming the porous asymmetric membrane comprises: dissolving a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer and, a polymer additive in a water-miscible polar aprotic solvent to form a porous asymmetric membrane-forming composition; and phase-inverting the porous asymmetric membrane forming-composition in a first non-solvent composition to form the porous asymmetric membrane. The polymer additive comprises hydrophilic functional groups, copolymerized hydrophilic monomers, or blocks of hydrophilic monomer repeat units. For example, the polymer additive can comprise a hydrophilic polymer or amphiphilic polymer. The porous asymmetric membrane can be a flat membrane or hollow fiber.

A porous asymmetric membrane comprises a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer; and a polymer additive. A separation module can be fabricated from the porous asymmetric membrane. A method of forming the porous asymmetric membrane comprises: dissolving a hydrophobic polymer comprising a poly(phenylene ether) or poly(phenylene ether) copolymer and, a polymer additive in a water-miscible polar aprotic solvent to form a porous asymmetric membrane-forming composition; and phase-inverting the porous asymmetric membrane forming-composition in a first non-solvent composition to form the porous asymmetric membrane. The polymer additive comprises hydrophilic functional groups, copolymerized hydrophilic monomers, or blocks of hydrophilic monomer repeat units. For example, the polymer additive can comprise a hydrophilic polymer or amphiphilic polymer. The porous asymmetric membrane can be a flat membrane or hollow fiber.

The present invention provides a method for preparing an aromatic polyamide porous membrane and an aromatic polyamide porous membrane prepared by the above method. The method for preparing an aromatic polyamide porous membrane includes the following steps: mixing an ionic liquid with an aromatic polyamide into a solvent to form a mixed solution; the mixed solution forming a membrane in a coagulation bath; and extracting with an extractant to remove the solvent and the ionic liquid from the membrane to yield a porous membrane. In the method of the present invention, the application of the ionic liquid would greatly reduce the application of additives; further, the ionic liquid has a high stability and is easy to be separated from other solvents and be recycled, which assures the safety during the usage and recycle thereof.

This invention provides a new high selectivity stable facilitated transport membrane comprising a polyethersulfone (PES)/polyethylene oxide-polysilsesquioxane (PEO-Si) blend support membrane, a hydrophilic polymer inside the pores on the skin layer surface of the PES/PEO-Si blend support membrane; a hydrophilic polymer coated on the skin layer surface of the PES/PEO-Si blend support membrane, and metal salts incorporated in the hydrophilic polymer coating layer and the skin layer surface pores of the PES/PEO-Si blend support membrane, and methods of making such membranes. This invention also provides a method of using the high selectivity stable facilitated transport membrane comprising PES/PEO-Si blend support membrane for olefin/paraffin separations such as propylene/propane and ethylene/ethane separations.

A porous composite membrane includes a porous support layer of a poly(phenylene ether) or poly(phenylene ether) copolymer; and an amphiphilic copolymer having a hydrophobic block and a hydrophilic block or graft, wherein the hydrophobic block includes a polystyrene block, a poly(phenylene ether) block, or a poly(phenylene ether) copolymer block; and an ultrathin, cross-linked, water permeable layer, which is the reaction product of an electrophilic monomer and a nucleophilic monomer, in contact with a side of the porous support layer. The reaction product can be a polyamide that is the interfacial condensation product of: an aromatic, polyfunctional acyl halide comprising of 3 to 6 acyl halide groups per aromatic ring and an aromatic polyamine comprising at least two primary amine groups and a maximum number of primary amine groups that is less than or equal to the number of acyl halide groups on the polyfunctional acyl halide.

The problem addressed by the present invention is to provide a separation membrane with superior permeation performance and separation performance and having few occurrences of defects. The present invention relates to a separation membrane wherein: the separation membrane has a layer (I) with a thickness of 0.5-100 ?m; letting, in a cross-section in the direction of thickness of the layer (I), region a be a region with a depth of 50-150 nm from a surface (surface A), region b a region with a depth of 50-150 nm from the other surface (surface B), and region c a region with a thickness of 100 nm where the depth from both surfaces is the same, the average pore diameter Pa for region a and the average pore diameter Pb for region b are both 0.3-3.0 nm and the average pore diameter Pc for region c is 3.0 nm or less; and the percentage of open area Ha for region a, the percentage of open area Hb for region b, and the percentage of open area Hc for region c satisfy the following equations. 2Hc<Ha 2Hc<Hb