高分子熔体和浓溶液流变性能的研究Ⅰ．具有高斯链限制作用的非线性粘弹性分子理论

STUDY ON THE RHEOLOGICAL BEHAVIOR FOR POLYMER MELTS AND CONCENTRATED SOLUTIONSⅠ.THE THEORY OF NON-LINEAR VISCOELASTICITY WITH GAUSSIAN China CONSTRAINTS IN ENTANGLED POLYMER MELTS

根据多重缠结模型和多重蠕动机理，用统计力学和动力学相结合的方法，建立了具有缠结限制作用的非线性粘弹性分子理论，计算了处于多重缠结态高分子链的构象统计，得到了高聚物熔体的粘弹性形变自由能，推导出了４种简单形变方式的应力－应变关系。从理论和实验上证实了非线性粘弹理论的时间效应和形变影响是非相关地相互独立的，得到了高聚物熔体和非线性粘弹性模量和柔量的表达式，当其松弛模量和推迟模量中ｎ＇＝１时，相应模量和柔量表达式分别还原为线性粘弹性的表达式。该理论能较好地预测高聚物熔体的非线性和线性粘弹性力学行为，并成功地预测到η０∝Ｍ￣（３．３～３．７）的经验关系式。

An approach of statistical mechanics and a unified molecular theory of non-linear viscoelasticitywith constraints of Gaussian chain entanglement for polymer melts were proposed.A multi-modemodel structure for a single polymer chain with n tail segments and N reversible entanglement sites onthe test polymer chain was developed. Based on the above model structure and the mechanism ofmolecular flow by the dynamical reorganization of entanglement sites,the probability distributionfunction of the end-to-end vector for a single polymer chain at entangled state and the viscoelastic freeenergy of deformation for polymer melts were calculated. The four types of stress-strain relation andthe memory function were derived from this theory.The above theoretical relations were verified bythe experimental data for various polymer melts.These relations were found to be in good agreementwith the experimental results.