Degradation behaviors of star-shaped PEG-b-PLLA copolymers

作者：Lin, Yaling^*; Wu, Min'er; Qiu, Yanwu; Zhang, Anqiang

来源：Polymer Materials Science and Engineering, 2013, 29(11): 67-70+75.

• Block copolymers films
• Degradation behavior
• Degradation mechanism
• Melt polycondensation
• Molar mass distribution
• Molecular weight polymers
• Phosphate buffer solutions
• PLLA

Triblock linearly, 3-arm or 4-arm star-shaped poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLLA) block copolymers were synthesized by melt polycondensation based on PEG and lactic acid. The degradation behaviors of these block copolymers films were investigated in a pH 7.2 phosphate buffer solution at 37°C. GPC profiles show bimodal molar mass distributions after a certain time of degradation for all the three copolymers, as the degradation advanced, the M¯ww of the lower molecular weight polymer does not change. According to XRD results, this polymer is crystalline PLLA, which confirms that the PLLA segment rarely degrades. Compiled with the contact angle and mass loss data, the degradation mechanism for PEG-b-PLLA copolymers is put forward: most of the hydrolysis happens to the ester bonds linked to PLLA and PEG segments, while few hydrolysis happens in the PLLA segments for its high crystallinity.

• 出版日期2013-11
• 单位华南理工大学