FLOW INDUCED CRYSTALLIZATION OF POLYETHYLENE MELTS
FLOW INDUCED CRYSTALLIZATION OF POLYETHYLENE MELTS
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DOI：
10.1016/0032-3861(73)90073-6
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发表时间：
1973-01-01
期刊：
影响因子：
4.6
通讯作者：
KELLER, A
中科院分区：
文献类型：
--
作者：
MACKLEY, MR;KELLER, A
已知流动系统中的纵向速度梯度使分子明显延伸，并且已经发现是聚乙烯从溶液中纤维状结晶的原因。本文给出了这种速度梯度对流动的可结晶聚合物熔体的影响的初步光学观测结果。通过使熔融聚合物流入两个彼此相对的孔中，特别是沿着系统的对称轴产生纵向速度梯度。结果发现，聚乙烯熔体的纤维结晶出现优先发生沿着这一轴，这意味着纵向速度梯度在生产中发挥了重要作用，这种纤维结晶。所得到的挤出物和长丝的结构影响进行了讨论。还提出了细纱布对聚合物熔体结晶的影响的其他观察结果。
Longitudinal velocity gradients in a flowing system are known to extend molecules appreciably and have been found to be responsible for the fibrous crystallization of polyethylene from solution. In this paper the preliminary optical observations are given of the effect this type of velocity gradient has on flowing crystallizable polymer melts. By flowing molten polymer into two mutually opposed orifices a longitudinal velocity gradient is generated specifically along the symmetry axis of the system. It was found that fibrous crystallization of polyethylene melt appeared to occur preferentially along this axis, implying that longitudinal velocity gradients play an important part in the production of this fibrous crystallization. The structural implications of the resulting extrudates and filaments obtained are discussed. Additional observations of the effect a fine gauze has on the crystallization of polymer melts is also presented.