A porous membrane comprising a thermoplastic resin, and having a densely structured layer, wherein the ratio of crystal strength to crystal strength of the thermoplastic resin in the densely structured layer is 5.0 or more.

A method for preparing the network-pore polyvinylidene fluoride membrane based on polyvinyl alcohol (PVA) gel includes the steps of (1) mix and stir PVA, masking agent and solvent, heat and dissolve the mixture evenly under 105 degree Celsius to obtain a PVA solution; (2) in the PVA solution, add PVDF and pore-forming agent, where the rest shall be added with the solvent until the total mass fraction sum is 1, stir, heat and dissolve the solution evenly to obtain the homogeneous casting solution; (3) the casting solution is filtered, deaerated, phase-separated and solidified as membrane A; (4) removes the PVA gel from membrane A to obtain membrane B; (5) membrane B is washed with water to remove the residual solvent to obtain the PVDF membrane with network-pore structure. The resulting PVDF membrane is an asymmetric membrane with an ultra-thin cortex and an interpenetrating network-pore sub-cortex structure.

The present disclosure belongs to the technical field of membrane separation, and discloses a preparation method of a Ti.sub.3C.sub.2T.sub.x MXene quantum dot (MQD)-modified polyamide (PA) reverse osmosis (RO) membrane. The preparation method includes the following steps: subjecting a Ti.sub.3C.sub.2T.sub.x MXene material to liquid nitrogen intercalation and interlayer expansion to obtain a Ti.sub.3C.sub.2T.sub.x MQD nanomaterial; preparing an aqueous phase solution with the Ti.sub.3C.sub.2T.sub.x MQD nanomaterial and an organic phase solution; soaking an ultrafiltration (UF) base membrane in the aqueous phase solution , and removing the aqueous phase solution on a surface of the UF base membrane through blow-drying; soaking the second UF base membrane in the organic phase solution to allow interfacial polymerization to form an active layer; and allowing a composite membrane obtained after the interfacial polymerization to stand, followed by a heat treatment to further promote the interfacial polymerization.

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 invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a polyimide precursor polymer is pyrolyzed to form a carbon molecular sieve membrane by heating, in a furnace, said polyimide precursor polymer to a final pyrolysis temperature of 600 C to 700 C at a pyrolysis heating rate of 3 to 7 C/minute from 400 C to the final pyrolysis temperature, the final pyrolysis temperature being held for a pyrolysis time of at most 60 minutes in a non-oxidizing atmosphere. In a particular embodiment, the cooling rate from the pyrolysis temperature is accelerated by methods to remove heat. The CMS membranes have shown an improved combination of selectivity and permeance as well as being particularly suitable to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.

An object of the present invention is to provide a porous hollow-fiber membrane satisfying both high strength and high pure-water permeation performance and at the same time, having high bending resistance. The present invention relates to a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane and when a photograph of a cross-section parallel to the longitudinal direction of the porous hollow-fiber membrane is binarized into a structure portion and a void portion, the following 1) and 2) are satisfied: 1) a proportion of an area of the void portion is from 20 to 50%, and 2) a value obtained by dividing a total of peripheral lengths of the void portions by a total of areas of the void portions is 2.0 ?m.sup.?1 or less.

The invention relates to membranes, monomers and polymers. The monomers can form polymers, which can be used for membranes. The membranes can be used in alkaline fuel cells, for water purification, for electrolysis, for flow batteries, and for anti-bacterial membranes and materials, as well as membrane electrode assemblies for fuel cells. In addition to the membranes, polymers and monomers and methods of using the membranes, the present invention also relates to methods of making the membranes, monomers and polymers.

A system for degassing a hydrocarbon fluid from a hydrocarbon liquid has a plurality of hollow tube membranes. The hollow tube membranes are formed of a plastic providing an inner support body and an outer selective layer which is denser than the inner support body. The inner support body is formed of spherulitic structures. A fuel supply system and a method ae also disclosed.

The present invention provides a separation membrane and a separation membrane element capable of exhibiting a good water production performance even at a high temperature and also excellent handleability and quality. The separation membrane of the present invention includes a separation membrane main body having a feed-side face and a permeate-side face; and a permeate-side channel member fixed onto the permeate-side face of the separation membrane main body, and the permeate-side channel member includes polypropylene as a main component and satisfies the following requirements (a) to (c): (a) a softening point temperature is 60? C. or higher; (b) a tensile elongation in a standard state is 10% or more; and (c) a yield point stress under a wet condition at 50? C. is 2 MPa or more.

An object of the present invention is to provide a separation membrane having high permeability and selective removability of divalent/monovalent ions. The separation membrane of the present invention includes a supporting membrane and a separation functional layer formed on the supporting membrane, in which the separation functional layer contains a polymerized product of a polyfunctional amine with a polyfunctional acid halide, the polyfunctional amine contains a polyfunctional aliphatic amine as a main component, the separation functional layer has a hollow protuberant structure, and the separation functional layer has a relative surface area of 1.1-10.0.