CHENG Song;ZHONG Cuihong;ZHOU Changren
. 2010, 41(04): 666-670.
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In this paper, hydroxyethyl chitosan (HECS) was prepared firstly by the reaction of chitosan and 2-chloroethanol. Then, the hydroxyethyl chitosan-graft-poly(D,L-lactide) (HECS-g-PDLLA) and chitosan-graft-poly(D,L-lactide) (CS-g-PDLLA) copolymers were synthesized by the bulk ring-opening polymerization of D,L-lactide onto HECS and CS respectively in the presence of tin(II) 2-ethylhexanoate catalyst. The prepared copolymers were characterized by FTIR, 1H-NMR, TGA, XRD and solubility. The results showed that the reaction activity of HECS obviously higher than that of CS, with the feeding ratio of n(D,L-LA):n(aminoglucoside) increased from 10:1 to 40:1, the grafting percentage of CS-g-PDLLA and HECS-g-PDLLA increased from 24.01% to 114.85% and from 77.42% to 380.51% respectively, and the average degree of polymerization of poly(D,L-lactide) branch chains in the two copolymers just mentioned above also rose from 0.61 to 2.48 and from 2.51 to 12.31 respectively. The feeding ratio of n(D,L-LA):n(aminoglucoside) had a strong influence on the structure and property of the graft copolymers, higher n(D,L-LA):n(aminoglucoside) feeding ratio led to copolymer with higher average degree of polymerization of poly(D,L-lactide) branch chains, and lower crystallinity and less thermal stability. The solubility of HECS-g-PDLLA was superior to that of CS-g-PDLLA in some organic solvents.