SURFACE MODIFICATION OF POLYMERS .3. PHOTO-INITIATED GRAFTING OF WATER-SOLUBLE VINYL MONOMERS AND INFLUENCE ON FIBRINOGEN ADSORPTION

Grafting of water soluble vinyl monomers in the superficial layer of styrene-(ethylene-co-butene)-styrene (SEBS) triblock copolymer has been performed by two different methods taking into account diffusion phenomena. The methods consist in successive or simultaneous diffusion of benzophenone and monomer into the film followed by u.v. irradiation of the film. Grafting of methacrylic acid and N-vinyl-2-pyrrolidone occurs by both methods, as detected by i.r. transmission spectroscopy. However, only grafting after simultaneous diffusion results in a change of surface properties, characterized by contact angle measurements, I-125 human fibrinogen adsorption studies and ATR i.r. spectroscopy. Diffusion of monomer and photo-initiator into SEBS, kinetics of grafting and influence of monomer and benzophenone concentration have been studied.