摘要
以高光学纯度右旋乳酸(D-LA)为单体合成了不同相对分子质量的右旋聚乳酸(PDLA),采用熔融共混法制备了工业级聚乳酸(PLA)/PDLA共混物。采用热变形温度测试、X射线衍射(XRD)和差示扫描量热(DSC)分别研究了PDLA含量和相对分子质量对PLA/PDLA共混物维卡软化温度(VST)、晶体类型和结晶及熔融行为的影响。结果表明,随着PDLA的加入,PLA的VST从64.6℃上升到最高152.3℃,且PDLA相对分子质量越小,PLA/PDLA共混物VST越高;XRD和DSC的结果均表明工业PLA与PDLA在熔融共混可形成立构复合晶体(SC),且极速冷却的共混物中不含PLA同质晶体(HC),说明PLA/PDLA共混物VST上升主要是由于SC晶体含量上升所导致;DSC研究发现,加入10%PDLA时,PLA/PDLA共混物的结晶温度(Tc)从95.9℃提高到133.4℃,表明了SC晶体是PLA的有效成核剂。
The poly （D-lactic acid）（PDLA） with various molecular weight was synthesized by using high optical purity of D-lactic acid（D-LA） to prepare the industrial polylactic acid （PLA） /PDLA blends through melt blending. The effects of PDLA content and molecular weight on the Vicar softening temperature （VST）, crystal type, crystallization and melting behavior of PLA/PDLA blends were studied by thermal deformation temperature tester, X-ray diffraction（XRD） and differential scanning calorimeter（DSC）. The results show that the VST of PLA and PLA/PDLA blends increases from 64.6 ℃ to 152.3 ℃ while the content of PDLA is up to 10%. The smaller the molecular weight of PDLA is, the higher the VST of PLA/PDLA blends is. The results of XRD and DSC show that stereocomplex crystallites （SC） can be formed during melt blending, and the rapid cooling of the blend does not contain PLA homogeneous crystal （HC）. It is indicated that the increase of VST in PLA/PDLA blends is mainly due to the increase of SC crystal content; the crystallization temperature （To） of the PLA/PDLA blend increases from 95.9 ℃to 133.4℃ while 10% PDLA is added, indicating that SC crystal is an effective nucleating agent for PLA.
作者
邹国享
屈鑫
赵彩霞
李锦春
Guoxiang Zou;Xin Qu;Caixia Zhao;Jinchun Li(J iangsu Key Laboratory of Environmentally Friendly Polymeric Materials, School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China)
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2018年第4期69-74,共6页
Polymer Materials Science & Engineering
基金
江苏省高校自然科学研究面上项目(15KJB150001)
关键词
聚乳酸
右旋聚乳酸
耐热性能
结晶性能
polylactic acid
poly （D-lactic acid）
heat resistance
crystallization property
