化学学报 ›› 2012, Vol. 70 ›› Issue (07): 881-888 .DOI: 10.6023/A1110151 上一篇    下一篇

研究论文

三臂PPO-PDLA-PLLA 嵌段共聚物的制备与结构及其立构复合体的结晶行为

赵辰阳, 石文鹏, 马艳, 李速明, 范仲勇   

  1. 复旦大学材料科学系 上海 200433
  • 收稿日期:2011-10-15 修回日期:2011-12-18 出版日期:2012-04-14 发布日期:2012-02-06
  • 通讯作者: 范仲勇
  • 基金资助:

    国家自然科学基金(No. 51073041)资助项目.

Synthesis, Structures and Characterization of Triarm PPO-PDLAPLLA Block Copolymers and Its Stereocomplex Crystallization Behavior

Zhao Chenyang, Shi Wenpeng, Ma Yan, Li Suming, Fan Zhongyong   

  1. Department of Materials Science, Fudan University, Shanghai 200433
  • Received:2011-10-15 Revised:2011-12-18 Online:2012-04-14 Published:2012-02-06
  • Supported by:

    Project was supported by the National Natural Science Foundation of China (No. 51073041).

以环氧丙烷聚醚三元醇(PPO)为起始剂, 开环聚合D 型丙交酯(DLA), 合成三臂环氧丙烷聚醚三元醇-聚右旋乳酸(PPO-PDLA)嵌段预聚体. 采用端基活化技术对预聚体进行端羟基活化, 再与L 型丙交酯(LLA)进行逐步开环聚合,合成了不同分子量的三臂环氧丙烷聚醚三元醇-聚右旋乳酸-聚左旋乳酸(PPO-PDLA-PLLA)嵌段共聚物. 采用红外(FTIR)、核磁(NMR)和凝胶渗透色谱(GPC)等对三臂PPO-PDLA-PLLA 嵌段共聚物的测试表明, 合成的嵌段共聚物分子链具有很高的立构规整度; 通过调节LLA 单体与PPO-PDLA 预聚体的投料比, 不仅可控制产物的分子序列结构, 而且样品的数均分子量可大于100 kDa. 差示扫描量热仪(DSC)和广角X 射线衍射(WAXD)结果显示, 三臂PPO-PDLAPLLA嵌段共聚物的异构体链段分子间生成立构复合晶体, 其熔点约为200 ℃, 且没有PLLA 均聚物链段结晶现象. 实验结果表明, 这是一类具有实际应用价值的新型耐热聚乳酸(PLA)材料.

关键词: 聚环氧丙烷, 聚乳酸, 立构复合物, 嵌段共聚物

The triarm poly(propylene oxide)-poly(D-lactide) (PPO-PDLA) copolymer was prepared by ring-opening polymerization (ROP) of D-lactide (DLA) with low unsaturated poly(propylene oxide) triols (PPO) as an initiator. The terminal hydroxyls of the prepolymer were activated by stannous octanoate [Sn(Oct)2]. Then a series of novel triarm poly(propylene oxide)-poly(D-lactide)-poly(L-lactide) (PPO-PDLA-PLLA) block copolymers were synthesized by ROP of L-lactide (LLA) with functioned PPO-PDLA prepolymer as a macroinitiator. Fourier transform infrared (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC) results confirmed the configuration of triarm PPO-PDLA-PLLA block copolymers with high isotacticity, and the number average molecular weight of the samples could be greater than 100 kDa . The block structure of copolymer chain could be readily adjusted in terms of LLA units and molecular weight of PPO-PDLA prepolymer. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) demonstrated that the stereocomplex PLAs (sc-PLAs) were formed between intermolecular PLLA and PDLA blocks without PLLA crystallization process. The melting temperature (Tm) of sc-PLA crystal was about 200 ℃, which was much higher than that of pure PLLA. These results show that the triarm PPO-PDLA-PLLA block copolymers could be promising as a heat-resistant poly(lactic acid) (PLA) material.

Key words: poly(propylene oxide), polylactide, stereocomplex, block copolymer