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首页> 外文期刊>Journal of Applied Polymer Science >Simplified theory for linear rheology of monodisperse linear polymers
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Simplified theory for linear rheology of monodisperse linear polymers

机译：单分散线性聚合物线性流变的简化理论

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A new version of the tube theory based on the de Gennes-Doi-Edwards reptation concept (reported in Likhtman and McLeish's work published in 2002) is evaluated, modified to allow for simplified computations, and used to study the relationship between zero-shear viscosity and molecular weight for monodisperse entangled linear homopolymers. The Likhtman-McLeish model combines self-consistent theories for contour length fluctuations and constraint release with reptation theory for monodisperse linear polymers. Because of the nature of the Rubinstein and Colby approach used for the treatment of constraint release, the related term is probabilistic and requires stochastic simulations for the calculation of the relaxation modulus G(t). This makes the Likhtman-McLeish model computationally difficult to use. In this work we solve this problem by generating an approximate closed-form solution for the stochastic term. Then analytical integration of the relaxation modulus function G(t) provides an expression for the zero-shear viscosity (eta(0)). Results of the computations of the zero-shear viscosity and of the slope of eta(0) versus molecular weight are compared with available experimental data for monodisperse entangled linear polystyrene and polyethylene (hydrogenated polybutadiene). The model is a major improvement over previous theoretical models, even if there is still some disagreement between the predictions and experimental data of the slope of eta(0) versus molecular weight. The possibility of inferring monomer chemistry-dependent parameters from the zero-shear viscosity remains a difficult task because of the introduction of a constraint-release parameter. Nevertheless, the model is a useful tool for the prediction of linear viscoelasticity data. (C) 2004 Wiley Periodicals, Inc.
机译：评估了基于de Gennes-Doi-Edwards复制概念的管理论的新版本（在Likhtman和McLeish的工作中于2002年发表报告），对其进行了修改以简化计算，并用于研究零剪切粘度之间的关系。和单分散缠结线性均聚物的分子量。 Likhtman-McLeish模型将轮廓线长度波动和约束释放的自洽理论与单分散线性聚合物的引申理论相结合。由于用于约束释放的处理的Rubinstein和Colby方法的性质，相关术语是概率性的，并且需要随机模拟来计算松弛模量G（t）。这使得Likhtman-McLeish模型在计算上难以使用。在这项工作中，我们通过为随机项生成近似闭合形式的解决方案来解决此问题。然后，松弛模量函数G（t）的分析积分提供了零剪切粘度（eta（0））的表达式。将零剪切粘度和eta（0）对分子量的斜率的计算结果与单分散缠结线性聚苯乙烯和聚乙烯（氢化聚丁二烯）的可用实验数据进行了比较。即使在eta（0）相对于分子量的斜率的预测和实验数据之间仍然存在一些分歧，该模型还是对先前理论模型的重大改进。由于引入了约束释放参数，从零剪切粘度推断单体化学相关参数的可能性仍然是一项艰巨的任务。尽管如此，该模型还是预测线性粘弹性数据的有用工具。 （C）2004年Wiley Periodicals，Inc.

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