Graft copolymerization of vinyl monomers onto, collagen. Part I. Phloxine sitized copolymerization in the presence of visible light

Abstract

Dye-sensitized photochemical graft copolymerization of vinyl monomers has been studied in aqucous medium using monochromatic light of λ = 546 nm. Oxygen was found to reduce the degree of grafting. Depending upon Ihe experimental conditions 18-40% of grafting was achieved. Poly(methyl methacrylate) gave higher % of grafting when compared with poly(mcthylacrylate) demonstrating that grafting reaction depends on the type of the viny monomer used. Proof of grafting was obtaincd by infra-red spectra of collagen-vinyl graft copolymers after enzymatic digestion. It is suggested Ihat the excitation of the dye to the singlet excited state followed by the transition to the triplet state by intersystem crossing may result in the abstraction of hydrogen from the collagen, creating active centres for the initiation of graft copolymerization of vinyl monomers.