Photoinduced graft copolymerization of dichlorodimethylsilane onto ethyl cellulose in homogeneous media

Abstract Photoinduced homogeneous graft copolymerization of dichlorodimethylsilane (DCDMS) onto ethyl cellulose (EC) was investigated in the absence and presence of photosensitizers, such as benzophenone, benzil and biacetal. The grafting process was carried out in benzene using UV radiation in the range 310–460 nm. The weight conversion, grafting percentage and grafting efficiency were determined as a function of the time of irradiation and the concentrations of monomer, EC and initiator. The structures of the photosensitizers were also considered. Various techniques were used to study the graft copolymers produced such as IR spectroscopy, nuclear magnetic resonance and thin layer chromatography. A Trommsdorf effect (accelerated grafting) was observed in certain systems. The rate of copolymerization of DCDMS onto EC was rapid ( R p = 2.1% min −1 ). The grafting efficiency values in the presence of the photosensitizers were found to be in the following order: benzil&>benzophenone&>biacetal. Pre-irradiation of samples increased the grafting percentage values. The mechanisms of formation of grafted chains in the absence and presence of photosensitizers are discussed.