Structural evolution of tensile deformed high-density polyethylene at elevated temperatures: Scanning synchrotron small- and wide-angle X-ray scattering studies
Structural evolution of tensile deformed high-density polyethylene at elevated temperatures: Scanning synchrotron small- and wide-angle X-ray scattering studies
复制标题
拉伸变形高密度聚乙烯在高温下的结构演变：扫描同步加速器小角和广角 X 射线散射研究
DOI：
10.1016/j.polymer.2009.06.063
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发表时间：
2009-07-31
期刊：
影响因子：
4.6
通讯作者：
Men, Yongfeng
中科院分区：
文献类型：
--
作者：
Jiang, Zhiyong;Tang, Yujing;Men, Yongfeng
采用同步辐射小角X射线散射（SAXS）和广角X射线散射（WAXS）相结合的方法，研究了在高温下单轴拉伸变形的高密度聚乙烯（HDPE）的结构演变与应变的关系。数据表明，当拉伸具有球晶结构的各向同性样品时，结晶块的层内滑动在小的变形下被激活，随后通过应力诱导的碎裂和再结晶过程产生层状微晶，其法线平行于拉伸方向。在120 ° C下拉伸等温结晶的HDPE样品表现出SAXS图的变化，其中应变类似于在室温下拉伸的淬冷HDPE所观察到的应变，这意味着构成薄片的结晶块的热稳定性仅取决于结晶温度。尽管拉伸温度和晶体厚度发生了很大变化，但与出现原纤结构的第一个指示相关的特征转变点处的应变基本上保持恒定。此外，WAXS实验被用来探测织构的变化，伴随着单轴拉伸和产量与微晶和无定形链段，和施加的应变的取向顺序参数之间的关系。这一结果支持了从拉伸变形开始就存在层间滑移的观点。(C)2009爱思唯尔有限公司版权所有。
The structural evolution of an ice-quenched high-density polyethylene (HDPE) subjected to uniaxial tensile deformation at elevated temperatures was examined as a function of the imposed strains by means of combined synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) techniques. The data show that when stretching an isotropic sample with the spherulitic structure, intralamellar slipping of crystalline blocks was activated at small deformations, followed by a stress-induced fragmentation and recrystallization process yielding lamellar crystallites with their normal parallel to the stretching direction. Stretching of an isothermally crystallized HDPE sample at 120 degrees C exhibited changes of the SAXS diagram with strain similar to that observed for quenched HDPE elongated at room temperature, implying that the thermal stability of the crystal blocks composing the lamellae is only dependent on the crystallization temperature. The strain at a characteristic transition point associated with the first indication for the occurrence of a fibrillar structure remains essentially constant in spite of the large changes in drawing temperature and crystalline thickness. In addition, WAXS experiments were used to probe the texture changes accompanying the uniaxial elongation and yield the relationship between the orientational order parameters associated with the crystallites and the amorphous chain segments, and the imposed strain. The results support the existence of intralamellar slip processes from the very beginning of tensile deformation. (C) 2009 Elsevier Ltd. All rights reserved.