Melting and Solid-Solid Transition of Polyethylene under Pressure
Melting and Solid-Solid Transition of Polyethylene under Pressure
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聚乙烯在压力下的熔化和固-固转变
DOI：
10.1143/jjap.19.1763
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发表时间：
1980
影响因子：
1.5
通讯作者：
T. Seto
中科院分区：
文献类型：
--
作者：
M. Hikosaka;S. Minomura;T. Seto
用差热分析法研究了31.4kb以下的未分馏聚乙烯（PE）的热行为，并绘制了其压力-温度相图。热谱图显示三个信号，表示为I、II和III。信号I，折叠链晶体的熔化，观察到高达8 kb。在4kb以下，信号II对应于斜方晶系固体的熔化;在4 - 8 kb之间，它对应于斜方晶系固体熔化和斜方晶系-六方晶系转变的叠加;并且在8 kb以上，它对应于单独的斜方晶系-六方晶系转变。在4kb以上，信号III对于在高压下结晶的样品具有新观察到的平坦形状，但是对于在1 B下结晶的样品具有峰形状。平坦信号对应于六方固体的连续熔化。分子量分布的影响，使聚乙烯在高压下表现为一个多组分系统进行了讨论。
The thermal behaviours of unfractionated polyethylene (PE) was observed up to 31.4 kb by differential thermal analysis, and its pressure-temperature phase diagram was obtained. The thermograms showed three signals, denoted I, II and III. Signal I, the melting of folded chain crystal, was observed up to 8 kb. Below 4 kb, signal II corresponded to the melting of orthorhombic solid; between 4∼8 kb, it corresponded to the superposition of the melting of orthorhombic solid and orthorhombic-hexagonal transition; and above 8 kb, it corresponded to the orthorhombic-hexagonal transition alone. Above 4 kb, signal III had a newly-observed flat shape for a specimen crystallized at elevated pressure, but a peak shape for a specimen crystallized at 1 b. The flat signal corresponded to the continuous melting of hexagonal solid. The effect of the molecular weight distribution which makes PE behave as a multi-component system at high pressure is discussed.