PLGA-(L-Asp-alt-dio1)(x)-PLGAs with different contents of pendant amino groups: Synthesis and characterization

摘要

A series of novel biodegradable multi-block copolymers PLGA-(L-Asp-alt-diol)(x)-PLGA with pendant amino groups was synthesized by ring-opening polymerization of D,L-lactide/glycolide(D,L-LA/GA) (75/25) using poly(N-CbZ-L-Asp-alt-diol)s as macroinitiator and stannous octoate as catalyst, in which the N-Cbz-L-Asp represents N-carbobenzyloxy-L-aspartic acid and diols are ethylene glycol, triethylene glycol, PEG200, and PEG600, respectively. Their structures and properties were characterized by FTIR, H-1 NMR, DSC, GPC, and elemental analysis (EA). The contents of the L-Asp unit in the copolymers were increased from 12.9 to 79.3 mmol . g(-1) with decreasing the chain length of the diol, while the glass transition temperatures of the copolymers were decreased from 27.1 to 11.7 degrees C with increasing the chain length of the diol. Thus, the results in this study provide a way to prepare biomaterials with different L-Asp unit densities or different number of bioactive sites as well as different properties through adjusting the chain length of the diol.