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首页> 外文期刊>Journal of Applied Polymer Science >Oriented crystallization of crosslinked cis-1,4-polybutadiene rubber
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Oriented crystallization of crosslinked cis-1,4-polybutadiene rubber

机译：交联的顺式1,4-聚丁二烯橡胶的定向结晶

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Crosslinked cis-1,4-polybutadiene (P13) rubber is known to undergo crystallization during mechanical deformation. This article presents small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and stress-relaxation studies of the structural development in crosslinked PB samples crystallized under various orientation regimes. The studies are concerned with isothermal crystallization at various temperatures (10 to -50 degrees C) and at constant elongation ratios (1-4.5) and hence with the effects of weak-to-intermediate and high orientations on oriented crystallization versus the behavior of unoriented specimens. The results for weak-to-intermediate orientations indicate a decrease in the long spacing during crystallization, which is accompanied by an almost constant lamellar thickness as well as a significant time lag between the development of crystallinity revealed by WAXS and SAXS intensity measurements. The SAXS integral intensity shows an overshoot; that is, the intensity reaches a maximum after some crystallization time and then decreases. Stress measured during crystallization with constant elongation ratios shows decay, which depends on the isothermal crystallization temperature and elongation ratio. Although the crystallization in the weak-to-intermediate orientations is interpreted on the basis of nucleation growth, the crystallization under high orientations is best interpreted on the basis of spinodal crystallization. The most pronounced feature of structural formation during crystallization under high orientations is an almost constant long period from nearly the beginning of the crystallization, even in a timescale in which other physical quantities such as the WAXS crystallinity, SAXS integral intensity, and stress still change with time, suggesting spinodal-like crystallization, orientation-induced instability of molten network chains and their ordering, which involves spinodal-elecomposition-like segregation of noncrystallizable parts (crosslinked points) and crystallizable parts (linear chains between the crosslinks) of network chains, and subsequent crystallization of crystallizable chains and pinning of the ordering process induced by crystallization. To the best of our knowledge, this work reports for the first time spinodal-like crystallization on oriented crosslinked polymer melts. (C0 2007 Wiley Periodicals, Inc.
机译：已知交联的顺式1,4-聚丁二烯（P13）橡胶在机械变形过程中会发生结晶。本文介绍了小角度X射线散射（SAXS），广角X射线散射（WAXS）和应力松弛研究，研究了在不同取向方案下结晶的交联PB样品的结构。这些研究涉及在各种温度（10至-50摄氏度）和恒定伸长率（1-4.5）下的等温结晶，因此涉及弱至中间和高取向对定向结晶与非定向结晶行为的影响。标本。弱到中间方向的结果表明，结晶过程中的长间距减小，这伴随着几乎恒定的层状厚度以及WAXS和SAXS强度测量显示的结晶度发展之间的显着时间差。 SAXS积分强度显示过冲;即，强度在一定的结晶时间后达到最大值，然后降低。具有恒定伸长率的结晶过程中测得的应力显示衰减，这取决于等温结晶温度和伸长率。尽管从弱到中间方向的结晶是根据成核生长来解释的，但在高方向上的结晶最好是根据旋节线的结晶来解释的。在高取向下结晶过程中，结构形成的最明显特征是几乎从结晶开始就处于几乎恒定的长时间内，即使在这样的时间范围内，WAXS结晶度，SAXS积分强度和应力等其他物理量仍会随时间，表明类节线形结晶，熔融网络链的取向诱导的不稳定性及其有序性，这涉及网络链的不可结晶部分（交联点）和可结晶部分（交联之间的线性链）的类旋节状元素分离，以及随后可结晶链的结晶和由结晶诱导的有序过程的固定。据我们所知，这项工作首次报道了定向交联聚合物熔体上类似旋节线的结晶。 （C0 2007 Wiley Periodicals，Inc.

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