Heterogeneous Graft Copolymerization of Chitosan Powder with Methyl Acrylate Using Trichloroacetyl−Manganese Carbonyl Co-initiation

A highly deacetylated chitosan powder was successfully trichloroacetylated under heterogeneous conditions. The trichloroacetylated chitosan powder was subsequently graft copolymerized heterogeneously with methyl acrylate using a Mn2(CO)10 co-initiator photoactivated with 436 nm light at room temperature. Reaction products were extracted with acetone in an attempt to separate homopolymer from the grafted powder. Portions of the grafted material (presumably surface grafted chitosan) were also removed from the bulk of the grafted powder. After monitoring the weights of reaction product and total polymer extracted from the reaction product (polymeric extract), gel permeation chromatography was used to resolve the polymeric extract into two separate species, assumed to be the grafted chitosan and homopolymer. With this general technique, graft and homopolymer yields for a series of grafting reactions were obtained. Graft yields greater than 600% (based on a percent weight increase of trunk polymer) were obtained, while 20−30% of the poly(methyl acrylate) formed was homopolymer.