Entanglement scaling in polymer melts and solutions
Entanglement scaling in polymer melts and solutions
复制标题
聚合物熔体和溶液中的缠结结垢
DOI：
10.1021/ma00196a031
复制
发表时间：
1989
期刊：
影响因子：
5.5
通讯作者：
J. Noolandi
中科院分区：
文献类型：
--
作者：
T. A. Kavassalis;J. Noolandi
在本文中，我们提出了聚合物熔体和溶液中分子缠结的几个通用标度定律，并将我们的预测与实验数据进行了比较。这里使用的模型是我们以前的工作的推广，其中缠结是用一个通用的拓扑参数n来描述的。我们发现，平均缠结间距作为聚合物化学和结构性质的函数的预测与实验数据非常吻合。该模型还预测了从纠缠链到非纠缠链在一定聚合度（Nc）上的转变，这与从稳态顺应性测量中确定的值有很好的相关性。模型的转变与范德华状态方程预测的液气临界点相似，直接导致剪切粘度的重复理论标度定律的偏离，而不需要引入新的机制。建立了溶液缠结的标度定律，并与实验数据很好地吻合。对溶液中纠缠效应开始的预测与德·热内关于链重叠的早期工作非常相似。用Ñ参数预测了重叠阈值密度和纠缠阈值密度之间的关系。
In thispaper, we develop several universal scaling laws for molecular entanglements in polymer melts and solutions and compare our predictions against experimental data. The model used here is a generalization of our previous work where entanglements were described by a universal topological parameter, N. Predictions for the mean entanglement spacing as a function of the polymer chemical and structural properties were found to be in good agreement with experimental data. The model also predicts a transition from entangled chains to unentangled chains at a degree of polymerization, Nc, that correlates well with values determined from steady-state compliance measurements. The model transition is shown to be analogous to the liquid-gas critical point predicted by the van der Waals equation of state and leads directly to departures from the reptation theory scaling laws for shear viscosity without invoking new mechanisms. Scaling laws are developed for entanglements in solution and are in good agreement with experimental data. Predictions made for theonset of entanglementeffects in solution closely parallel earlier work on chain overlap by de Gennes. A relationship between the overlap threshold density and entanglement threshold density is predicted in termsof the parameter Ñ.