A method for improving the airtightness of a building or a room in a building, includes using a vapor barrier membrane on the inner face of the walls of the building or the room in the building, wherein the vapor barrier membrane is a humidity-regulating membrane including an active portion which includes a middle layer having a thickness of 2 m to 200 m, and consisting of a biopolymer having a water vapor permeability coefficient P.sub.1 which increases with average relative humidity and which, when determined at 23 C. and at an average relative humidity of 25.5%, is at least 300 Barrers, and, on either side of the middle layer and in contact with the latter, two outer layers with a thickness of 100 nm to 20 m, and consisting, independently of each other, of an organic polymer having both a water vapor permeability coefficient P.sub.2.

An ion-exchange membrane is disclosed here including ion-permeable layers impregnated with an ion-exchange material and arranged in an order from one face of the membrane to the opposite face of the membrane such that opposing layers in the supporting membrane substrate provide sufficiently identical physical properties to substantially avoid irregular expansion when in a salt solution. The ion-permeable layers including at least one non-woven layer and at least one reinforcing layer.

The present invention relates to a comprehensive evaluation method for the performance of contaminated flat membranes, which relates to the field of sewage and waste resource technology. The present invention firstly analyzed the composition of the surface elements of the contaminated membrane by EDX to determine the type of membrane contamination, and then designed different cleaning schemes for organic or inorganic pollution to obtain a sample membrane. When the tensile strength of the contaminated membrane decreased more than 50% than that of the control membrane, it is a waste membrane; when the tensile strength decreased less than 50% and the membrane flux reduced more than 30%, it is a waste membrane; when tensile strength decreased less than 50%, membrane flux reduced less than 30% and the carbon footprint was more than 188 g, it is a waste membrane; otherwise was a old membrane. The comprehensive evaluation method of the present invention can quantitatively, quickly and comprehensively define the difference between the old membrane and the waste membrane, and provides the basis for the selection of the contaminated membrane and the process of the regeneration and reuse.

A method for manufacturing a filter membrane for inhibiting microorganisms includes the following steps: obtaining a nano-zinc precursor and dissolving it into water, adding at least one reducing agent and interfacial agent to the water, thereby reducing zinc ions of the nano-zinc precursor to zinc particles so as to form liquid having nano-zinc particles; respectively placing the liquid having nano-zinc particles and a polymer material into plastic masterbatch process equipment, respectively volatilizing the fluid having nano-zinc particles and polymer material through the plastic masterbatch process equipment, performing air extraction and mixing by the plastic masterbatch process equipment, and adding at least one grafting agent to perform a mixed graft link, allowing the nano-zinc particles and polymer material to be linked together stably so as to form a plastic masterbatch having nano-zinc particles; and making the plastic masterbatch into a filer membrane through film making equipment.

A composite membrane including an organic polymer matrix and a plurality of porous inorganic particles is disclosed, wherein each of the porous inorganic particles has a plurality of pores arranged while forming a channel in a predetermined direction, and wherein an average length of the porous inorganic particles in a direction parallel to the channel is less than three times the average maximum length of the porous inorganic particles in the direction perpendicular to the channel.

An anion exchange membrane includes an anion exchange resin layer 3 reinforced with a backing material sheet 5. The anion exchange resin layer 3 includes an anion exchange resin that has as an anion exchange group a pyridinium group formed by protonation of a pyridyl group, and a vinyl chloride resin as a thickener. The backing material sheet 5 is made of a polyethylene woven fabric.

A bipolar membrane in which a cation-exchange membrane and an anion-exchange membrane are joined to each other, wherein a leakage ratio of gluconic acid at 60 C. is not more than 1.0%, and the cation-exchange membrane is supported by a polyolefin reinforcing member and, further, contains a polyvinyl chloride.

A membrane having permselectivity for perchlorate ion is prepared using certain types of quaternary ammonium salts contained in a polymeric matrix material, which may be plasticized. Such membranes are useful in electrodialysis processes, whereby perchlorate-contaminated aqueous compositions are purified.

A carbonized PVDC copolymer useful for the separation of an olefin from its corresponding paraffin may be made by heating a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 20 micrometers to a pretreatment temperature of 100? C. to 180? C. to form a pretreated polyvinylidene chloride copolymer film and then heating the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350? C. to 750? C. A process for separating an olefin from its corresponding paraffin in a gas mixture is comprised of flowing the gas mixture through the aforementioned carbonized polyvinylidene chloride (PVDC) copolymer to produce a permeate first stream having an increased concentration of the olefin and a second retentate stream having an increased concentration of its corresponding paraffin.

A carbon molecular sieve (CMS) membrane may advantageously be made by pyrolyzing a membrane precursor composition comprised of a carbon forming polymer (e.g., polyimide) blended with a polyvinylidene chloride copolymer (PVDC), the polyvinylidene chloride copolymer being the reaction product of at least 60% to 97% by weight of vinylidene chloride and at least one other comonomer and the carbon forming polymer to polyvinylidene chloride copolymer has a weight ratio of greater than 1 to 99. The membrane precursor composition may be formed by dissolving the carbon forming polymer and PVDC in a solvent to form a dope solution. The dope solution may be shaped, for example, into an asymmetric hollow fiber. The asymmetric hollow fiber may be heated to a temperature to dehydrochorinate the PVDC and then subsequently heated in a non-oxidizing atmosphere to carbonize the polymers of the shaped membrane to form the CMS membrane.