摘要
以L-乳酸为单体、季戊四醇为引发剂,采用缩聚法合成了短链四臂星形聚乳酸(4sPLA),随后经不饱和酸酐对其端基改性,合成了含不饱和端基的四臂星形聚乳酸预聚物(M4sPLA),最后通过自由基引发M4sPLA的固化反应制备热固性聚乳酸,重点研究了缩聚时间对预聚物和热固性聚乳酸产物的影响。结果表明:延长缩聚时间可明显提高羟基引发效率和星形聚乳酸的分子量,降低杂质含量,使其分子量分布更窄;随直接缩聚时间的延长,固化产物具有更高的交联密度,经20 h直接缩聚的固化产物具有最好的力学性能、热稳定性以及完善的微观结构。
This work presents the preparation of thermoset poly(lactic acid)(PLA)through polycondensation and cross-linking reactions.Firstly,four-armed star-shaped poly(lactic acid)(4sPLA)with short chains was synthesized by polycondensation using L-lactic acid as monomer and pentaerythritol as initiator,and was hydroxyl-terminated using methacrylic anhydride to obtain the unsaturated-group-terminated star-shaped oligomer precursor(M4sPLA)capable of cross-linking and solidification.Then,the thermoset PLA samples were obtained by a free-radical-initiated cross-linking reaction,and the effects of polycondensation duration on mechanical properties and thermal stability of the thermoset PLA product were studied.The results showed that the reaction initiation efficiency can be obviously enhanced by increasing the polycondensation duration,which lead to low inpurity content,high molecular weight and low polydispersity of 4sPLA.Moreover,the prolonged polycondensation duration is conducive to higher cross-linking density of the thermally cured PLA product.The most satisfactory mechanical properties,thermal stability and microstructure of the thermoset PLA could be achieved when the polycondensation reaction duration was 20h.
作者
谢鹏飞
陈勰
丁峰
张乃文
李建波
任杰
XIE Pengfei;CHEN Xie;DING Feng;ZHANG Naiwen;LI Jianbo;REN Jie(College of Materials Science and Engineering,Tongji University,Shanghai 201804)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第6期1042-1046,共5页
Materials Reports
基金
上海汽车工业科技发展基金会(1006)
国家高技术研究发展计划(2013AA032202)
国家自然科学基金(51203118)~~
关键词
热固性聚乳酸
四臂星形聚乳酸(4sPLA)
缩聚
L-乳酸
季戊四醇
甲基丙烯酸酐
端基改性
聚合时间
热稳定性
thermoset poly(lactic acid)
four-armed star-shaped poly(lactic acid)(4sPLA)
polycondensation
L-lactic acid
pentaerythritol
methacrylic anhydride
terminal group substitution
polymerization duration
thermal stability
