酶降解星型立构复合聚乳酸结构与性能的研究  

Study on Structure and Properties of Star-shaped Stereocomplex Polylactic Acid during Enzyme-catalyzed Degradation

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作  者:李远翔[1] 吴小蒙[1] 范田堂 范仲勇[1] LI Yuanxiang;WU Xiaomeng;FAN Tiantang;FAN Zhongyong(Department of Materials Science,Fudan University,Shanghai 200433,China)

机构地区:[1]复旦大学材料科学系,上海200433

出  处:《复旦学报(自然科学版)》2018年第6期780-788,共9页Journal of Fudan University:Natural Science

基  金:国家自然科学基金(51673046;51373041)

摘  要:以三枝化聚环氧丙烷醚(poly(propylene oxide)triols,PPO)为起始剂,引发D型丙交酯(D-LA)开环聚合,制备星型聚环氧丙烷醚-聚右旋乳酸(PPO-PDLA)共聚物;再用辛酸亚锡(Sn(Oct)2)与PPO-PDLA端羟基进行封端,得到了星型PPO-PDLA-SnOct预聚物;再将星型PPO-PDLA-SnOct预聚物作为大分子引发剂与L型丙交酯(L-LA)开环聚合,合成了星型聚环氧丙烷醚-聚右旋乳酸-聚左旋乳酸(PPO-PDLA-PLLA)嵌段共聚物.利用蛋白酶K对非晶态PLLA链段选择性降解的特性,研究了立构复合PPO-PDLA-PLLA材料的降解及凝聚态转变行为.差示扫描量热法(DSC)测试结果表明在降解过程中膜材料的熔点>200℃,表明酶降解过程中膜样品的立构复合结构稳定.X射线衍射表征(WAXD)发现降解过程中立构复合晶体沿(110)晶面发生结晶完善现象,降解46d后,晶粒侧向尺寸增长了约4.3nm.扫描电子显微镜(SEM)对微观结构的观测表明,晶区为网状结构连续相,在其中岛状分布的非晶区在降解过程中逐渐刻蚀去除,最终形成多孔形貌.Three-arm poly(propylene oxide)-block-poly(D-lactic acid)(PPO-PDLA)was prepared by ring-opening polymerization of D-lactide(D-LA)using three arm poly(propylrnr oxide)(PPO)as initiator.Then PPO-PDLA copolymer was reacted with Sn(Oct)2 to obtain endcapped PPO-PDLA-SnOct.The endcapped PPO-PDLA-SnOct was then used as a macroinitiator for the ring-opening polymerization of L-lactide(L-LA)to synthesize star shape PPO-PDLA-PLLA copolymer.As proteinase K selectively degrade amorphous PLLA segments,the degradation and condensed state transition behavior of PPO-PDLA-PLLA were investigated.The results showed that only aTm about 200℃ for all stereocomplex block samples during degradation.The WAXD results showed that stereocomplex crystalline size of(110)plane slightly increased about 4.3 nm,indicating the enhancement of stereocomplex crystallization during degradation.SEM observation of porous structure supported that the crystalline region was a continuous phase of the network structure,in which the island-shaped amorphous region was gradually etched away during the degradation process,finally forming aporous morphology.

关 键 词:立构复合 聚乳酸 酶降解 

分 类 号:O631[理学—高分子化学]

 

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