Abstract Almost all flows of polymers are accompanied by evolution of the molecular configuration, which has a great influence on material properties. However, the existing molecular configuration evolution models are mainly limited to the configuration evolution of a single molecular chain in a dilute solution ignoring intermolecular forces; it is impossible to predict the evolution of the molecular configuration of polymer melt with a complex entanglement network. Thus, we propose a non-isothermal compressible viscoelastic molecular configuration evolution model for polymer melt using non-equilibrium irreversible thermodynamic methods. The proposed model can more accurately describe the rheological properties of polymer melts compared with the commonly used XPP model, especially at high shear rates. The predicted molecular configuration in rotary Couette flow agrees well with the measured dielectric anisotropy results. Finally, the present model and a simulation method are successfully applied to predict the evolution of polymer molecular configuration and birefringence in three-dimensional injection compression molding, and the predicted birefringence is consistent with the measured results. A typical skin-core structure, resulting from the competition of the flow field and the molecular Brownian thermal motion in the injection molding, is investigated.

中文翻译：

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聚合物熔体分子构型演化模型与非平衡不可逆热力学模拟

摘要 几乎所有聚合物的流动都伴随着分子构型的演变，这对材料的性质有很大的影响。然而，现有的分子构型演化模型主要局限于单分子链在稀溶液中的构型演化，而忽略了分子间作用力；无法预测具有复杂缠结网络的聚合物熔体的分子构型演变。因此，我们提出了一种使用非平衡不可逆热力学方法的聚合物熔体的非等温可压缩粘弹性分子构型演化模型。与常用的 XPP 模型相比，所提出的模型可以更准确地描述聚合物熔体的流变特性，尤其是在高剪切速率下。旋转库埃特流中预测的分子构型与测量的介电各向异性结果非常吻合。最后，该模型和一种模拟方法成功地应用于预测三维注射压缩成型中聚合物分子构型和双折射的演变，预测的双折射与实测结果一致。研究了一种典型的皮芯结构，它是由注射成型中流场和分子布朗热运动的竞争引起的。并且预测的双折射与实测结果一致。研究了一种典型的皮芯结构，它是由注射成型中流场和分子布朗热运动的竞争引起的。并且预测的双折射与实测结果一致。研究了一种典型的皮芯结构，它是由注射成型中流场和分子布朗热运动的竞争引起的。