A thermodynamic approach to the stress‐induced crystallization in cross‐linked rubbers
A thermodynamic approach to the stress‐induced crystallization in cross‐linked rubbers
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DOI：
10.1002/pol.1978.180160911
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发表时间：
1978-09
期刊：
影响因子：
--
通讯作者：
W. Wu
中科院分区：
文献类型：
--
作者：
W. Wu
对预拉伸橡胶中的结晶现象进行了热力学处理。重点是定义扩链或折叠链晶体结构的热力学稳定性条件。发现伸展链结构在高于未交联聚合物在拉伸状态下的各向同性熔点的温度下是热稳定的，而折叠链结构则不是。下面，网络结构的拉伸比决定了哪种晶体结构更稳定。还讨论了伸展/折叠晶体结构转变的临界拉伸比与温度和分子量之间的关系。通过这项工作预测的结晶度在T的温度下变为零，T是交联体系的各向同性熔点。T的值随着交联密度的增加而减小，这与文献中报道的实验数据一致。
The thermodynamic treatment of crystallization phenomena in a prestretched rubber was undertaken. Emphasis was put on defining conditions for the thermodynamic stability of the extendedor folded‐chain crystal structure. The extended‐chain structure is found to be stable thermodynamically at temperatures higher than the isotropic melting point of un‐cross‐linked polymerTin the stretched state, while the folded chain one is not. BelowT, the stretch ratio of the network structure determines which crystal structure is more stable. The relation among the critical stretch ratio for the extended/folded crystalline structure transition, temperature, and molecular weight is also discussed. The crystallinity predicted by this work becomes zero at a temperature ofT, the isotropic melting point of a cross‐linked system. The value ofTdecreases with increasing cross‐link density, and this is consistent with the experimental data reported in the literature.