Abstract:

Using a new method—microwave-irradiation to get the chitosan-graft-poly(D,L-lactide)(CS-g-PLA) copolymer, the graft copolymerization was carried out by ring opening polymerization using stannous octoat (Sn(Oct)2) as catalyst without any organic solvent. In order to find the best reaction condition, the effection of different condition in copolymerization were studied by the orthogonality experiment, including power of microwave, dosage of Sn(Oct)2, reaction time and temperature. And the graft copolymers were characterized by FTIR, 1H-NMR, DSC, X-RD and TG. The results showed that microwave-assisted ring-opening polymerization can obtain the CS-g-PLA copolymer successfully and raipdly.Compared with chitosan, the grafting copolymerization has destroyed the original crystallinity of chitosan, the products’ onset temperature of degradation and thermal stability descended. The feed ratio(D,L-lactide /aminoglucoside units molar ratio) had a strong influence on the structure and properties of CS-g-PLA copolymer, higher feed ratios led to graft copolymer with higher average degree of polymerization of polylactide branch chains, and the lower crystallinity and onset temperature of degradation.

Key words: microwave-assisted synthesis,chitosan,poly(D,L-lactide),graft copolymer