Studies on graft copolymerization onto cellulose derivatives. XXIX. Photo‐induced graft copolymerization of methyl methacrylate onto chitin and oxychitin

Abstract

AbstractGraft copolymerization of methyl methacrylate (MMA) onto chitin and oxidized chitin was carried out by a noncatalytic photo‐induced and a photo‐sensitized method. The isolation method of grafted chains without a decrease in their degree of polymerization (DP) by sulfuric acid hydrolysis and the effects of some factors on the conversion and the grafted chain length have been studied.In case of the photo‐induced graft copolymerization, if a small amount of dimethylformaldehyde (DMF) is added in the polymerization system, the induction period is shortened and the degree of grafting and the apparent number of grafted chains increase. The degree of grafting and the apparent number of grafted chains of the oxidized chitin containing a small amount of CO groups are greater than those of the untreated chitin, but a further increase in CO groups decreases these values.In the presence of this two species of the chitin samples, the polymerization reaction was carried out as functions of monomer and chitin concentrations. From these results, the mechanisms of the photo‐induced graft copolymerization were discussed. It is also clear that the conversion and the apparent number of grafted chains by the noncatalytic photo‐induced method are generally larger than those by the photo‐sensitized method, and the grafting activity with hydrogen peroxide (HPO) is higher than that with azobisisobutyronitrile (AIBN).