THERMAL-DECOMPOSITION OF POLYMERIC HYDROPEROXIDES AND SURFACE GRAFTING OF ACRYLAMIDE

Reaction of a styrene-butadiene-styrene block copolymer (SBS) with pho togenerated singlet oxygen produces clusters of polymeric hydroperoxid es. At 100 degrees C they decompose about 100 times faster than low mo lecular weight hydroperoxides by a mechanism involving mainly radical- induced reactions. SBS hydroperoxides have been used to initiate the g rafting of acrylamide in boiling aqueous solutions of that monomer. Gr afting is restricted to the surface of the material since acrylamide d oes not diffuse into SBS. Its surface becomes very hydrophilic and, as a consequence, the contact angle with water droplets decreases from 9 0 degrees to 25 degrees. Adsorption of fibrinogen onto the modified su rface is also reduced to 60% of its initial value.