On the phenomenology of chain-extended crystallization in polyethylene
On the phenomenology of chain-extended crystallization in polyethylene
复制标题
聚乙烯扩链结晶现象学
DOI：
10.1080/14786437408222081
复制
发表时间：
1974
影响因子：
1.6
通讯作者：
B. Turner
中科院分区：
文献类型：
--
作者：
D. Bassett;B. Turner
在0~6kbar压力范围内，研究了聚乙烯的熔融和结晶过程。体积和温度测量表明，在4kbar以上，分级聚合物熔融和结晶分成两个明显可分辨的阶段。这是由于在∼3kbar处形成了三相点的新的高压聚乙烯相。该相在比体积和比熵上介于斜方相固体和熔体之间，但更接近后者，并且是液晶或固体。进一步表明，扩链聚乙烯的形成与结晶过程中发生的两个放热过程(在4kbar以下未分解)有关。这就引出了一种假设，即链状折叠结晶是通过从熔体直接转变为正交形固体而发生的，而扩链聚乙烯则是在中间相介入结晶时产生的。这一假说似乎能够解释大多数已知的f。
Abstract The melting and crystallization of polyethylene have been examined in the pressure range 0 to 6 kbar. Volumetric and thermal measurements show that fractionated polymer melts and crystallizes in two clearly resolved stages above 4 kbar. It is suggested that these are due to the formation of a new, high pressure phase of polyethylene with a triple point at ∼ 3 kbar. This phase is intermediate in specific volume and entropy between orthorhombic solid and melt, but closer to the latter, and is either liquid-crystalline or solid. It is shown further that the formation of chain-extended polyethylene correlates with the occurrence of two exothermic processes (unresolved below 4 kbar) during crystallization. This leads to the hypothesis that whereas chain folded crystallization occurs by direct transformation from melt to orthorhombic solid, chain-extended polyethylene results when the intermediate phase intervenes in crystallization. This hypothesis appears capable of accounting for most of the known f...
影响因子：
2.5
作者：
B. Wunderlich;L. Melillo
通讯作者：
B. Wunderlich;L. Melillo