材料科学
热变形温度
甲基丙烯酸缩水甘油酯
维卡软化点
共聚物
艾氏冲击强度试验
丙交酯
复合材料
结晶
韧性
聚合物
高分子化学
化学工程
软化点
极限抗拉强度
工程类
作者
Shihao Deng,Hongwei Bai,Zhenwei Liu,Qin Zhang,Qiang Fu
出处
期刊:Macromolecules
[American Chemical Society]
日期:2019-02-08
卷期号:52 (4): 1718-1730
被引量:92
标识
DOI:10.1021/acs.macromol.8b02626
摘要
Stereocomplexation of enantiomeric poly(l-lactide)/poly(d-lactide) (PLLA/PDLA) chains opens up a great opportunity toward sustainable PLA engineering plastic with exceptional heat resistance and durability. However, the processing and applications of stereocomplex-type PLA (SC-PLA) are significantly blocked by its inferior melt stability (i.e., the weak melt memory effect in triggering complete SC crystallization, which makes it hard to obtain exclusive formation of SC crystallites in melt-processed products) and inherent brittleness. In this contribution, we demonstrate an unprecedented strategy to address these obstacles by one-pot reactive melt blending of the equimolar PLLA/PDLA blend with reactive poly(ethylene–methyl acrylate–glycidyl methacrylate) (E-MA-GMA) in the presence of catalyst, where both the stereocomplexation and the grafting of some PLLA/PDLA chains onto E-MA-GMA backbones take place simultaneously and competitively. Intriguingly, the E-MA-graft-PLA copolymer in situ formed can substantially improve the melt stability of SC-PLA matrix as compatibilizer, and thus highly crystalline SC-PLA/E-MA-GMA blend products with exclusive SC crystallites can be readily obtained by injection molding. Moreover, some E-MA-graft-PLA can also strengthen the blend interface as interfacial enhancer, which gives rise to an increase in the toughening efficiency. As a result, the obtained SC-PLA/E-MA-GMA blends exhibits impressive heat resistance (the Vicat softening temperature and heat deflection temperature are as high as 201 and 174 °C, respectively) and impact toughness (the notched Izod impact strength is close to 65 kJ/m2). Notably, their comprehensive performance is superior to some commercial petroleum-derived engineering plastics. Overall, the one-pot syntheses of copolymer by in situ grafting could open up a new horizon for creating super-robust SC-PLA-based engineering plastic using industrial melt-processing technologies.
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