Preparation and Degradation Properties of Hydroxyethyl Chitosan-g-Poly(D,L-Lactide) Copolymers

The goal of the present study was to investigate the degradation of hydroxyethyl chitosan-g-poly(D,L-lactide) (HECS-g-PDLLA) copolymers in vitro. For this purpose, HECS-g-PDLLA copolymers were firstly synthesized by bulk ring-opening polymerization with different nD,L-lactide:naminoglucoside feed ratio. Then, a series of poly(D,L-lactide), chitosan and HECS-g-PDLLA copolymers films were prepared by solution casting method, and their degradation were carried out in vitro in saline water at 37 °C. The degradation properties were investigated by measurement of pH value, weight loss, and changes in the composition and structure of the HECS-g-PDLLA copolymers films with time. Results showed that the degradation of the HECS-g-PDLLA copolymers occurred firstly on the poly(D,L-lactide) side chains. The degradation rate of the graft copolymers obviously faster than that of CS, and can be controlled by changing the value of nD,L-lactide:naminoglucoside. Due to the alkalinity of CS, the pH value of saline water for HECS-g-PDLLA copolymers degradation higher than that of PDLLA.