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Graft copolymerization of styrene onto mercaptochitin has been examined. Chitin was first tosylated to give tosylchitin, which was subsequently transformed into mercaptochitin. Athough the graft copolymerization was carried out in suspension, it proceeded efficiently to give chitin derivatives having polystyrene branches, a novel type of hybrid materials composed of a natural polysaccharide and a synthetic polymer. Under appropriate conditions, the grafting percentage reached 970%, indicating the high efficiency of the mercaptochitin as an initiator for the polymerization of styrene. The resulting graft copolymers exhibited glass transition phenomena at 115 °C and showed high swelling in organic solvents as a result of the introduction of polystyrene branches. Hydrolytic degradation of the chitin main chain allowed the isolation of the side chains, and the polystyrene isolated from the graft copolymer with a grafting percentage of 940% had Mn, Mw, and Mw/Mn values of 9.74 × 104, 2.55 × 105, and 2.62. Thes...

In the presence of Lewis acids, cationic species were formed from iodochitin at the carbons bearing an iodo group, and graft copolymerization of styrene proceeded efficiently in nitrobenzene or somewhat less efficiently in nitromethane. As a catalyst, SnCl 4 was superior to TiCl 4 . Grafting percentages were as high as 800% under appropriate conditions. On irradiation by an excimer laser, the C-I bonds of iodochitin were cleaved to free radicals which initiated styrene grafting with low grafting yields but formation of very little homopolystyrene

Tosylation of chitin was accomplished by interfacial condensation to give tosylchitins expected to be useful as soluble and reactive precursors for chemical manipulations under mild conditions. The reaction was efficient even at low temperatures. Tosylation was quantitative with a 20-fold excess of tosyl chloride. Free amino groups in the tosylchitins were acylated to form well-defined structures. The tosylchitins with substitution degrees above 0.4 were soluble in common polar organic solvents. The resulting tosylchitins underwent efficiently reactions such as acetylation and iodination to fully acetylated tosylchitins and iodochitins