摘要
聚丙交酯(PLA)和乙交酯-丙交酯共聚酯(PLGA)是性能优异的可降解聚酯材料,发展绿色、环境友好的催化剂实现丙交酯和乙交酯的本体熔融聚合具有重要的科学意义和实际应用价值.本文研究了ZnCl_(2)、MgCl_(2)和FeCl_(3)与3种有机碱构成的Lewis酸碱对在丙交酯(LA)本体熔融聚合的催化作用.研究了包括Lewis酸碱对类型、比例和反应时间对LA开环聚合反应的影响.这3类Lewis酸碱对在180℃高温下表现出较好的热稳定性和催化活性.其中FeCl_(3)/DBU催化体系能够同时实现高单体转化率和分子量.同时,FeCl_(3)/DBU能够有效催化LA和GA的随机共聚,通过调控LA和GA的单体投料比可以制备不同摩尔组成的PLGA共聚酯.
Polylactide(PLA)and poly(lactic-co-glycolic acid)(PLGA)are degradable polyesters with excellent properties.It is practically important to develop green and environment friendly catalysts that can realize the bulk melt ring opening polymerization(ROP)of lactide and its copolymerization with glycolide.In this work,we report the bulk polymerization of lactide catalyzed by Lewis pairs composed of ZnCl_(2),MgCl_(2)or FeCl_(3)and three different oganobases.We then systematically studied the effects of Lewis pair structures,mixing ratios and polymerization time on the ROP of lactide.The three types of Lewis pairs all showed great thermal stability and high catalytic activities at 180℃.In particular,the combination of FeCl_(3)/DBU can effectively catalyze the ROP of lactide and its copolymerization with glycolide at 180℃to obtain high monomer conversion and high molecular weight at the same time.The resulting PLA homopolymer can reach molecular weight as high as 64.2 kg/mol via bulk polymerization,which are comparable to other metal catalytic systems.The molecular structures of PLLA and PLGA copolymer were verified by^(1)H-NMR spectroscopy and MALDI-TOF MS.The microstructures of the PLGA copolymers were carefully analyzed byC-NMR,and the results showed that the monomer sequence lengths can be easily modulated by varying the feeding ratio of two monomers.The resulting PLGA copolymer were all amorphous solids,and the glass transition temperature decreased with the increase of GA contents.
作者
马钰琨
沈勇
李志波
Yu-kun Ma;Yong Shen;Zhi-bo Li(Key Laboratory of Biobased Polymer Materials,Shandong Provincial Education Department,College of Polymer Science and Engineering;College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2022年第8期923-932,共10页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号22031005,22075160)
国家重点研究计划(项目号2021YFA1500095)资助项目。
关键词
聚乳酸
丙交酯
开环聚合
路易斯酸碱对
可降解高分子
Polylactide
Lactide
Ring opening polymerization
Lewis acid-base pair
Degradable polymer
