Molecular Mechanism Leading to Memory Effect of Mesomorphic Isotactic Polypropylene

doi:10.1002/polb.24051

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	Molecular Mechanism Leading to Memory Effect of Mesomorphic Isotactic Polypropylene
	Li, Xiangyang1 ; Liu, Yanping 2,3; Tian, Xingyou1 ; Cui, Kunpeng 4,5
	2016-08-15
发表期刊	JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
摘要	In this study, memory effect of mesomorphic isotactic polypropylene (iPP) was investigated using polarized optical microscope and small-angle X-ray scattering. Differing from classical memory effect, mesomorphic iPP melt had a higher growth rate and a higher memory temperature. The relative growth rate increased with increasing crystallization temperature. Lauritzen-Hoffman plots indicated that the increased growth rate arose from reduced surface nucleation barrier. The highest memory temperature was estimated to be 185 degrees C, which was close to the equilibrium melting point of iPP crystal. Additionally, Small-angle X-ray scattering measurements showed that a liquid crystal layer might exist between lamellar and amorphous layers. Based on above results, a crystallization model was proposed. In the mesomorphic iPP melt, there exist aggregates structurally similar to beta phase except a-phase crystal residuals, which cannot act as nucleation sites or transform to b crystal through surface nucleation. The only way for the aggregate is to transform to a crystal during crystal growth. The aggregate decreases the surface nucleation barrier and promotes the helical growth, leading to higher growth rate. Only when the aggregate relaxes to polymer coils through thickening at a higher temperature, can the memory effect be erased. (C) 2016 Wiley Periodicals, Inc.
文章类型	Article
关键词	Activation Energy Crystallization Growth Rate Lamellar Memory Effect Mesomorphic Ipp Poly(Propylene) (Pp) Saxs Small-angle X-ray Scattering Surface Nucleation
WOS标题词	Science & Technology ; Physical Sciences
DOI	10.1002/polb.24051
关键词[WOS]	SHEAR-INDUCED NUCLEATION ; ISOTHERMAL CRYSTALLIZATION ; POLYMER CRYSTALLIZATION ; MELT MEMORY ; SYNDIOTACTIC POLYPROPYLENE ; CRYSTAL NUCLEATION ; SINGLE-CRYSTALS ; SELF-NUCLEATION ; POLYETHYLENE ; FLOW
收录类别	SCI
语种	英语
项目资助者	National Natural Science Foundation of China(51303166) ; National Natural Science Foundation of China(51303166) ; National Natural Science Foundation of China(51303166) ; National Natural Science Foundation of China(51303166) ; National Center for International Research of Micro-nano Molding Technology ; National Center for International Research of Micro-nano Molding Technology ; National Center for International Research of Micro-nano Molding Technology ; National Center for International Research of Micro-nano Molding Technology ; Key Laboratory for Micro Molding Technology of Henan Province(MMT2016-03) ; Key Laboratory for Micro Molding Technology of Henan Province(MMT2016-03) ; Key Laboratory for Micro Molding Technology of Henan Province(MMT2016-03) ; Key Laboratory for Micro Molding Technology of Henan Province(MMT2016-03)
WOS研究方向	Polymer Science
WOS类目	Polymer Science
WOS记录号	WOS:000381295400004
引用统计	被引频次：19[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.hfcas.ac.cn:8080/handle/334002/24581
专题	应用技术研究所
作者单位	1.Chinese Acad Sci, Hefei Inst Phys Sci, Inst Appl Technol, Hefei 230088, Peoples R China 2.Zhengzhou Univ, Natl Ctr Int Res Micronano Molding Technol, Zhengzhou 450002, Peoples R China 3.Zhengzhou Univ, Key Lab Micro Molding Technol Henan Prov, Zhengzhou 450002, Peoples R China 4.Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230026, Peoples R China 5.Univ Sci & Technol China, Coll Nucl Sci & Technol, Hefei 230026, Peoples R China
推荐引用方式 GB/T 7714	Li, Xiangyang,Liu, Yanping,Tian, Xingyou,et al. Molecular Mechanism Leading to Memory Effect of Mesomorphic Isotactic Polypropylene[J]. JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS,2016,54(16):1573-1580.
APA	Li, Xiangyang,Liu, Yanping,Tian, Xingyou,&Cui, Kunpeng.(2016).Molecular Mechanism Leading to Memory Effect of Mesomorphic Isotactic Polypropylene.JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS,54(16),1573-1580.
MLA	Li, Xiangyang,et al."Molecular Mechanism Leading to Memory Effect of Mesomorphic Isotactic Polypropylene".JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS 54.16(2016):1573-1580.

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