Further studies on polyethylene crystallized under stress: Morphology, calorimetry, and stress relaxation
Further studies on polyethylene crystallized under stress: Morphology, calorimetry, and stress relaxation
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DOI：
10.1080/00222347108212556
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发表时间：
1971-09
期刊：
影响因子：
--
通讯作者：
M. J. Hill;A. Keller
中科院分区：
文献类型：
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作者：
M. J. Hill;A. Keller
如前所述，应力首先诱导形成少量独特的、假定为纤维状的晶体，这些晶体的链沿着应力方向(类型I)，然后形成横向生长的片层(类型II)。对由此产生的系统的研究已分三部分恢复。1.形态。在足够高的应力水平下，薄片都是平行的，在薄膜中可以看到它们的边缘。通过金饰，可以清楚地勾勒出边缘面，从而可以明确地确定片层厚度。发现由低角X射线(和电子)衍射得到的大间距与单个晶片的厚度无关，而与包括中间区域在内的整个周期有关。讨论了这些发现对总体聚合物中低角度极大值的意义的影响。2.量热法。以前有报道说，在高温下去应力后，观察到I型晶体消失。
Abstract As previously established, stress induces first the formation of a small amount of distinctive, presumably fibrous crystals with the chains along the stress direction (type I) which then nucleates transversely growing lamellae (type II). The study of the resulting system has been resumed in three parts. 1. Morphology. At high enough stress levels the lamellae are all parallel and are seen edge-on in thin films. By gold decoration, the edge faces could be clearly delineated and thus the lamellar thickness could be unambiguously determined. It was found that the large spacings obtained by low-angle X-ray (and electron) diffraction correlated not with the thickness of the individual lamellae but with the full periodicity including the intervening regions. Implications of these findings for the meaning of low-angle maxima in the bulk polymer in general are discussed. 2. Calorimetry. It was reported previously that type I crystals were observed to disappear on removal of stress at the temperature of t...