【作者】 李伟； 马艳； 范仲勇；

【Author】 Wei Li;Yan Ma;Zhongyong Fan;Department of Materials Science,Fudan University;

【机构】 复旦大学材料科学系；

【摘要】 以三臂聚环氧丙烷(PPO)引发右旋丙交酯(D-LA)以及左旋丙交酯(L-LA)逐步开环聚合,制备了聚右旋乳酸(PDLA):聚左旋乳酸(PLLA)1:1、1:2和1:4不同对映体链段比的PPO-PDLA-PLLA嵌段共聚物。采用DSC、WAXD研究了不同对映体链段比及结晶温度对共聚物结晶动力学及晶体结构的影响,POM观测了球晶生长过程及形态。实验表明,在等温结晶过程中,嵌段共聚物均只生成立构复合晶,与不同对映体链段长度比无关。随着不同对映体链段比例的降低,等温结晶速率及球晶生长速率(G)降低,1:1的PDLA:PLLA样品立构复合结晶能力最强。更多还原

【Abstract】 Poly(propylene oxide)-block-poly(D-lactic acid)-block-poly(L-lactic acid)(PPO-PDLA-PLLA) block copolymers with different enantiomer ratios(PDLA: PLLA=1:1, 1:2, and 1:4) were synthesized. Differential scanning calorimetry(DSC) and wide-angle X-ray diffraction(WAXD) were used to investigate the effect of enantiomer ratio and crystallization temperature on crystallization kinetics and crystal structures. Spherulite growth behaviors and morphology were monitored by polarized optical micrographs(POM). For all the PPO-PDLA-PLLA copolymers, only stereocomplex crystallite was formed in isothermal melt-crystallization process, irrespective of enantiomer ratio. The overall crystallization rates decreased with decreasing of PDLA: PLLA ratios, and the fastest crystallization rate of copolymers occurred at PDLA: PLLA=1:1.更多还原