On interfering nuclei and their novel kinetics during the crystallization of polyethylene from the melt
On interfering nuclei and their novel kinetics during the crystallization of polyethylene from the melt
复制标题
聚乙烯熔体结晶过程中的干扰核及其新动力学
DOI：
10.1016/s0032-3861(00)00875-2
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
D. Bassett
中科院分区：
文献类型：
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作者：
M. I. A. E. Maaty;D. Bassett
在高温下，线性聚乙烯从静止熔体中结晶为具有倾斜褶皱表面的片层。因此，当生长在线状细胞核上形成行结构时，形成的第一个薄片在对称地倾斜于行轴的两个方向上外延形成。随着径向距离的增加，优势片层逐渐变宽、分离，并与排垂直，但仍有倾斜的褶皱面。两种条件下的等温生长速率都是恒定的，但后一种条件下的等温生长速率比初始条件下的等温生长速率快3-4倍。我们认为，在制度1条件下，生长较快的原因是次级核对相邻片层的干扰减少。干涉核的概念，竞争相同的分子，也为先前报道的聚乙烯和长正构烷烃的动力学效应以及在这种线性分子的结晶中存在更快生长的优势片层提供了令人信服的解释。
At high temperatures, linear polyethylene crystallizes from the quiescent melt as lamellae with inclined, ∼{201}, fold surfaces. Accordingly, when grown on linear nuclei to form row structures, the first lamellae to form do so epitaxially in two orientations symmetrically inclined to the axis of the row. With increasing radial distance, dominant lamellae widen, separate and become normal to the row albeit still with inclined fold surfaces. Isothermal growth rates are constant in both conditions but that for the later one is 3–4 times faster than the initial one. It is suggested that faster growth is a consequence of diminishing interference between secondary nuclei on neighbouring lamellae growing under Regime I conditions. The concept of interfering nuclei, competing for the same molecule, also provides a convincing explanation for previously reported kinetic effects in polyethylene and long n-alkanes as well as the presence of faster-growing dominant lamellae in the crystallization of such linear molecules.