Rapid synthesis and characterization of chitosan-g-poly(D,L-lactide) copolymers with hydroxyethyl chitosan as a macroinitiator under microwave irradiation

作者：Luo Binghong; Yang Jing; Zhao Jianhao; Hsu ChungEn; Li Jianhua; Zhou Changren^*

来源：Journal of Applied Polymer Science, 2012, 125.

DOI：10.1002/app.35603

• biodegradable
• graft copolymers
• polyesters
• polysaccharides
• synthesis

Hydroxyethyl chitosan (HECS) was first prepared by the reaction of 2-chloroethanol with chitosan (CS). Then, CS-g-poly(D,L-lactide) (PDLLA) copolymers were synthesized through the ring-opening polymerization of D,L-lactide with CS and HECS as the macroinitiators, respectively, under microwave irradiation. The optimal synthesis conditions obtained by an orthogonal experiment were as follows: microwave power = 10 W, temperature = 130 degrees C, irradiation time = 15 min, and catalyst concentration = 0.05 mol %. The reactivity of CS was improved by hydroxyethylation, which contributed to a higher percentage of grafting. Compared with the conventional thermal polymerization, the microwave polymerization method showed a significantly higher polymerization rate and improved efficiency. An enhanced percentage of grafting ranging from 236.25 to 317.50%, and an average degree of polymerization of PDLLA side chains ranging from 13.25 to 24.17 were achieved under microwave irradiation when the value of nD,L-lactide/nminoglucoside units was increased from 20 : 1 to 40 : 1. The higher percentage of grafting facilitated decreases in the crystallinity and thermal stability of the copolymers, which were attributed to the weakening intramolecular and intermolecular hydrogen bonds of CS.

• 单位
  暨南大学; 济南大学