Carbon Dioxide Induced Crystallization for Toughening Polypropylene

被引:25
作者
Bao, Jin-Biao [1 ,2 ]
Liu, Tao [1 ]
Zhao, Ling [1 ]
Hu, Guo-Hua [2 ]
机构
[1] E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China
[2] CNRS Nancy Univ INPL ENSIC, Lab React & Proc Engn, F-54001 Nancy, France
基金
中国国家自然科学基金;
关键词
HIGH-DENSITY POLYETHYLENE; ISOTACTIC POLYPROPYLENE; MALEIC-ANHYDRIDE; IMPACT STRENGTH; MORPHOLOGY; BEHAVIOR; PHASE; FORM; SOLUBILITY; COPOLYMERS;
D O I
10.1021/ie200407p
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
This study proposes a novel process for significantly toughening isotactic polypropylene (iPP) by finely tuning and controlling the structure and morphology of iPP. The toughness of injection-molded iPP specimens can be significantly improved by controlled shearing, CO2-induced recrystallization, and adequate cooling without loss of strength. The distribution and structure of the iPP samples before and after toughening were characterized by polarized optical microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry, to investigate the structure-property relationship. Under shear, a high degree of orientation can be obtained with "shish-kebab" crystals formed in the shear zone. During the subsequent CO2 treatment, a crystal network morphology can be formed as a result of an increase in the numbers of primary lamellae and crosshatched subsidiary lamellae, which leads to an increase in toughness. Wide-angle X-ray diffraction patterns indicate that quenching in ice-water of scCO(2)-treated iPP promotes the formation of nanosized mesomorphic phase domains in the shear zone, which further toughens the iPP. The impact strength of the best toughened iPP sample was found to be over 12 times that of the original sample without loss in tensile strength and modulus.
引用
收藏
页码:9632 / 9641
页数:10
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