The Secretary of State for Defence in Her Britannic Majesty's Government

Her Majesty the Queen in Right of Canada, As Represented by the Minister

The Secretary of State for Defence in Her Brittanic Majesty's Government

Peter J Fydelor

Kenneth B Pithouse

Barbara J Ringrose

Lionel B Adams

Gordon Partridge

Ronald A Miller

David E Taylor

Jonathan W Ramsay

A hydrophilic, water-swellable graft copolymer comprising polyethylene vinyl acetate (PEVA) containing between 8 and 30 wt. % vinyl acetate units, radiation graft copolymerized with an ethylenic carboxylic acid and subsequently heat treated in an aqueous hydroxide solution at a temperature greater than the softening point of the PEVA. A process for the preparation of such a polymer by radiation induced graft copolymerization of PEVA with an ethylenic carboxylic acid and subsequent heat treatment in an aqueous hydroxide solution at a temperature greater than the softening point of the PEVA is also described. The polymers of the invention are suitable for making into devices for various applications, but are particularly useful for making surgical devices, such as laparascope tubes, urethal catheters, endovascular cannuli, for endoscopic access, and as endo-prostheses. Some examples of surgical uses of such devices using the invention are described.

Process for the preparation of a hydrophilic water swellable graft

A biocompatible surgical device comprises at least at its surface a hydrophilic thermoplastic graft copolymer which is an ethylenic carboxylic acid, selected from acrylic acid and alkyl substituted acrylic acids graft copolymerized onto a base polymer. The base polymer is preferably selected from polyolefins, especially polyethylene and polypropylene, partially and fully fluorinated polyolefins, especially polytetrafluoroethylene and polyetherurethanes. Graft copolymerization of the monomers to the base polymer is initiated preferably by ionizing radiations, especially gamma radiation. The reaction takes place preferably in an aqueous solution and in the presence of a homopolymerization inhibitor such as ferrous sulphate or potassium ferricyanide. The base polymer may be graft copolymerized throughout its entire thickness or to a known depth in one or more of its surfaces. The former material exhibits high elastic properties while the latter exhibits a low elasticity and low moduli. The biocompatible devices described may be in the form of prostheses, especially vascular prostheses, wound dressings, especially in the treatment of skin loss and open wounds, and body fluid contacting surfaces for use in extra-corporeal, body fluid treating devices.

Biocompatible material comprising a base polymer bulk graft polymerized

Polymeric materials are disclosed in which a synthetic essentially hydrophobic base polymer has at least in its surface region a crosslinked polar comonomer graft in the surface region at least of which there are metal atoms or ions which are chemically bound and which cannot be removed by solution processes. There are also disclosed three processes by which such materials may be produced. The deposition of a complex metal compound, the contacting of the graft with a metal compound both followed by heating, and graft copolymerization with a metal containing comonomer. There is also disclosed a method of ensuring a good bond between a polymeric material and a coating which includes a preliminary surface graft with a polar comonomer.

Graft co-polymers

An Electrolytic cell having a separator positioned between a positive electrode and a negative electrode is disclosed in which the separator is a moulding of polymer material derived from a particulate polymer material having a polar graft-copolymerized surface. The separator may be deposited as a coherent film of the surface of an electrode by sintering the particulate material into a coating around the electrode using heat and/or pressure. Alternatively a shaped article such as a case, envelope, sheet film or the like may be prepared and used to wrap around or encase an electrode.

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Swindon, United Kingdom

Peter J Fydelor