Structural evolution of tensile-deformed high-density polyethylene during annealing: Scanning synchrotron small-angle X-ray scattering study
Structural evolution of tensile-deformed high-density polyethylene during annealing: Scanning synchrotron small-angle X-ray scattering study
复制标题
拉伸变形高密度聚乙烯在退火过程中的结构演变：扫描同步加速器小角度 X 射线散射研究
DOI：
10.1021/ma0627572
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发表时间：
2007-10-02
期刊：
影响因子：
5.5
通讯作者：
Rieger, Jens
中科院分区：
文献类型：
--
作者：
Jiang, Zhiyong;Tang, Yujing;Rieger, Jens
采用同步辐射小角X射线散射（SAXS）技术研究了高密度聚乙烯（HDPE）在单轴拉伸变形过程中的结构演变，并对其在不同温度下退火后的应变行为进行了分析。结果证实，在拉伸变形过程中，层内块滑移在小变形下被激活，随后是应力诱导的碎裂和再结晶过程，产生较薄的层片，其法线平行于拉伸方向。原来的剪切层片经历了严重的内部变形，使他们更不稳定比新开发的更薄的层片。因此，退火导致原始微晶甚至在中等应变下熔化，其中应力诱导的碎裂和再结晶刚刚开始，并产生沿拉伸方向沿着排列的明显不同形式的层状堆叠。结果表明，在中等应变拉伸过程中新形成的层状结构在较低温度下保持稳定。只有在120 ℃的非常高的退火温度下，它们才能熔化，导致层状结构的各向同性分布。
The structural evolution of high-density polyethylene subjected to uniaxial tensile deformation was investigated as a function of strain and after annealing at different temperatures using a scanning synchrotron small-angle X-ray scattering (SAXS) technique. The results confirm that in the course of tensile deformation intralamellar block slips were activated at small deformations followed by a stress-induced fragmentation and recrystallization process yielding thinner lamellae with their normal parallel to the stretching direction. The original sheared lamellae underwent severe internal deformation so that they were even less stable than the newly developed thinner lamellae. Accordingly, annealing results in a melting of the original crystallites even at moderate strains where the stress-induced fragmentation and recrystallization just sets in and generates a distinctly different form of lamellar stacks aligned along the drawing direction. It was found that the lamellae newly formed during stretching at moderate strains remain stable at lower temperature. Only at a very high annealing temperature of 120 degrees C can they be melted, leading to an isotropic distribution of the lamellar structure.