高分子熔体和浓溶液的流变性能研究Ⅱ．具有高斯链缠结限制作用的物料函数及其粘弹性参数确定的新法

STUDY ON THE RHEOLOGICAL BEHAVIOR FOR POLYMER MELTS AND CONCENTRATED SOLUTIONS Ⅱ. THE MATERIAL FUNCTIONS WITH GAUSSIAN CHAIN CONSTRAINTS AND A NEW METHOD FOR DETERMINATION OF THEIR PARAMETERS FROM FLOW CURVES

从前一报所提出的具有多重缠结限制作用的高分子非线性粘弹性理论出发，推导出了高分子流体的回忆函数、一般化本构方程和多种流场下多种物料函数：①稳态简单剪切流；②稳态单轴拉伸流；③小振幅的振动剪切流。建议了一种从流动曲线来测定物料函数中的粘弹性参数η０、ｎ＇和α的新方法，用该法测定了多种聚合物熔体的粘弹性参数。最后以大量高分子熔体的流变性能实验数据，对所得到的动、静态剪切物料函数进行了验证，证实了我们所提出高分子熔体的非线性粘弹性分子理论同实验能很好的符合。

An integral constitutive equation and a set of material function for describing the strain history of polymer melts were formulated in terms of the Cauchy-Green and Finger tensors. A simple memory function was derived from the theory of non-linear viscoelasticity with constraints of entanglements for polymer melts and substituted into the Oldroyed-Walters-Fredickson constitutive equation. An integral constitutive equation for polymer melts was consequently obtained. Some material functions of the constitutive equation related to certain test flow are examined as follows: ① Simple steady shear flow3 ② Steady elongation flow; ③ Small-amplitude oscillatory shear flow.A new method for determination of the linear viscoelastic parameters for material function was proposed. These theoretical relations for state and dynamic shear flows were compared with experimental data from our laboratory and references for various polymer melts and concentrated solutions.A good agreement between the theory and experiment was achieved.