Selective gas-permeable films

Claim 1

A selective gas-permeable film comprising a crosslinked copolymer product of (1) an α,ω-bifunctional polyorganosiloxane of the general formula ##STR16## in which each Z represents a halogen atom, a hydroxy group, an alkoxy group, an amino group, a dimethylamino group, a diethylamino group or a dipropylamino group, R and R' independently represent a hydrogen atom, a methyl group, a phenyl group, a halogenated alkyl group or a vinyl group, and n is an integer from 5 to 200; with a mixture of: (2) a styrene polymer having an aromatic ring at each side chain thereof and an average molecular weight ranging from 1,000 to 30,000 and selected from the group consisting of poly-p-hydroxystyrene, poly-3,5-dimethyl-4-hydroxy-styrene, poly-p-hydroxystyrene bromide, poly-3-methoxy-4-hydroxystyrene and mixtures thereof, poly-o-hydroxystyrene, poly-p-aminostyrene, polystyrenesulfonic acid, polyvinylbenzoic acid, polyvinylsalicylic acid, poly-2,5-dihydroxystyrene, polyisopropenylphenol, copolymers of the styrene polymers with acrylic esters, etherized derivatives of polyhydroxystyrene which have recurring units of the formula ##STR17## in which R" represents Si(CH 3 ) 3 or an alkyl group having 1 to 18 carbon atoms, and o and p are integers sufficient to define the molecular weight range; and (3) a functional end group-bearing polymer having an average molecular weight of from 1,000 to 10,000 and represented by the general formula HO--R.sub.1 --R.sub.2).sub.i R.sub.1 --OH in which each R 1 represents a dihydric phenol residue, R 2 represents a reactive residue capable of condensing with the phenolic hydroxyl groups to form polyester, polyether or polyurethane, and i is an integer from 5 to 50.