期刊
EUROPEAN POLYMER JOURNAL
卷 70, 期 -, 页码 400-411出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.eurpolymj.2015.07.040
关键词
Poly(L-lactide); Oxalamide compounds; Nucleation; Crystallization kinetics
资金
- National Natural Science Foundation of China [51303067]
- Natural Science Foundation of Jiangsu Province [BK20130147]
The bio-based and biocompostable semi-crystalline poly(L-lactide), PLLA, suffers from slow crystallization rate. Oxalamide compounds are tailor-made as novel self-assembly-type nucleators in this work, which altered significantly the crystallization kinetics of the PLLA. The terminal structures (cyclohexyl, benzyl and phenyl) show strong influence on their self-organization and nucleation efficiency. Their self-organizing temperature sequence (measured via rheology) in the PLLA melt is cyclohexyl > benzyl > phenyl 190 degrees C, while the nucleation activity follows a reverse order. Consequently, the compounds capped with phenyl group exhibit the highest nucleation efficiency. The oxalamide compounds in the PLLA melt showed varied depression in crystallization and dissolution temperatures, demonstrating a designable miscibility. Interestingly, the dissolved oxalamide compounds could organize into shish-like superstructures that subsequently triggered shish-kebab morphology of PLLA crystals free of any flow or shear. With the aid of phenyl-capped oxalamide compound (e.g. 0.75 wt.%), the crystallization of PLLA occurred at 108 degrees C with a crystallinity of 35% even upon fast cooling (20 degrees C/min), while the half-life crystallization time (t(0.5)) was dramatically reduced by 95% in a wide temperate range. In addition, the oxalamide compounds could significantly reduce the PLLA crystal size without modification on crystal form. (C) 2015 Elsevier Ltd. All rights reserved.
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