Effect of Molecular Weight on Phase Transition of Polyethylene under High Pressure
Effect of Molecular Weight on Phase Transition of Polyethylene under High Pressure
复制标题
高压下分子量对聚乙烯相变的影响
DOI：
10.1143/jjap.20.617
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发表时间：
1981
影响因子：
1.5
通讯作者：
M. Hikosaka
中科院分区：
文献类型：
--
作者：
M. Hikosaka
本文用X射线衍射方法证实了作者在热研究中提出的聚乙烯（PE）在高压下相变时表现为多组分体系的分子量分布效应。分级聚乙烯结晶成一个扩展链晶体（ECC）显示了一个单组分系统的平衡连续的一级相变。但两种不同分子量的PE混合物或结晶成ECC的未分级PE显示出六方固体的连续熔融，这是二元或多组分体系熔融的特征。另一方面，PE结晶成折叠链晶体（FCC），没有表现出平衡转变。这些结果证实了我们以前的建议，并得出结论，只有单分散ECC-PE可以被视为一种纯的材料。
The effect of the molecular weight distribution which makes polyethylene (PE) behave as a multi-component system in the phase transition under high pressure suggested by the authors from thermal study was confirmed by an X-ray method. Fractionated PE crystallized into an extended-chain crystal (ECC) showed the equilibrium successive first-order phase transition of a one-component system. But a PE mixture of two different molecular weights or unfractionated PE crystallized into ECC showed continuous melting of hexagonal solid characteristic of the melting of binary or multi-component systems. PE crystallized into folded-chain crystal (FCC), on the other hand, showed no equilibrium transition. These results confirm our previous suggestion and it is concluded that only monodisperse ECC-PE can be regarded as a thermodynamically pure material.