Compatible polymer blend compositions in the form of films comprising polyalkylene oxide and aromatic polyethersulphone

Claim 2

A polymer composition in the form of a film which composition comprises a compatible blend of an alkylene oxide polymer not containing units derived from a cyclic ester and an aromatic polyethersulphone.

Claim 3

A polymer composition according to claim 1 wherein the alkylene oxide polymer is a homopolymer or a copolymer containing at least 50 mole % of alkylene oxide units.

Claim 4

A polymer composition according to either claim 1 or claim 2 wherein the alkylene oxide polymer is a polyethylene oxide, a polypropylene oxide, or a poly(tetramethylene) oxide homo- or copolymer.

Claim 5

A polymer composition according to claim 3 wherein the alkylene oxide polymer is a polyethylene oxide of molecular weight at least 100,000.

Claim 6

A polymer composition according to any one of the preceding claims wherein the alkylene oxide polymer is water-soluble.

Claim 7

A polymer composition according to any one of the preceding claims wherein the polyethersulphone has the repeat unit or the repeat unit alone or in conjunction with other repeat units.

Claim 8

A polymer composition according to any one of the preceding claims wherein the compatible blend has a composition of 5-95 weight % of alkylene oxide polymer and correspondingly 95-5 weight % of aromatic polyethersulphone.

Claim 9

A polymer composition according to any one of claims 1 to 6 wherein the compatible blend has a composition of 2-25 weight % of alkylene oxide polymer and correspondingly 98-75 weight % of aromatic polyethersulphone.

Claim 10

A polymer composition according to any one of the preceding claims in the form of a transparent film.

Claim 11

A polymer composition according to any one of the preceding claims wherein the film has a contact angle of its surface to water of 4 60°,

Claim 12

A polymer composition according to any one of the preceding claims in the form of a porous or semi-permeable film.

Claim 13

A polymer composition according to claim 11 in the form of a porous or semi-permeable film used in a membrane separation system or as the encapsulating membrane in a system for the sustained and/or predictable release of a biologically active species in unit dosage form.

Claim 14

A process for the production of a polymer composition in the form of a film according to either claim 11 or claim 12 which process comprises forming a film by solvent casting a composition comprising a blend of an alkylene oxide polymer not containing units derived from a cyclic ester and an aromatic polyethersulphone but allowing some of the solvent casting medium to remain in the film, and leaching the film with a liquid which is miscible with at least one component of the solvent casting medium and is also a non-solvent for the polymers of the blend.