Preparation of hydrophilic materials by radiation grafting of poly(ethylene-co-vinyl acetate)

Poly(ethylene-co-vinyl acetate) copolymer tubes, of varying wall thickness and vinyl acetate (VA) content were radiation graft copolymerised with acrylic acid using the mutual method. Subsequent thermal treatment in aqueous potassium hydroxide solutions gave rise to a structure that was capable of swelling in an aqueous medium whilst still retaining its strength and integrity. The effect of the degree of grafting, thermal treatment temperature and VA content on hydrophilicity and dimensional change were measured in both water and Hartmann’s solution. For a given set of grafting parameters, the higher the VA content, the higher the graft, and the greater the thermal treatment temperature, the greater the dimensional change on hydration. In the hydrated form the tubes had a lubricious surface, facilitating their use for medical devices such as catheters, cannulae and stents.