Flory-Huggins格子上的混合亥氏函数模型

A MIXING HELMHOLTZ FUNCTION MODEL BASED ON FLORY - HUGGINS LATTICE

在Florg-Huggins格子中,引入有效的链插入几率表达过量熵,以Wohl式表达过量内能,建立了多元系链状高分子溶液的分子热力学模型.二元系的计算结果表明:在r_1=1,r_2=1～10000条件下,该模型比Freed理论更接近于计算机模拟结果;在其它条件下,两者基本吻合.Flory-Huggins理论因引入平均场近似,结果与之相差甚远.本文模型不仅能够描述常见的三元系统液液平衡,而且能描述三元系环形液液平衡曲线.

By introducing effective chain - insert probability into the excess entropy and adopting Wohl expression for the excess internal energy, a molecular thermodynamic model for a multicomponent system based on the Flory - Huggins lattice model has been established. For binary system, when r1equals to 1 and r2 varies from 1 to 10000, the results calculated with the new model is more consistent with computer - simulation data than those calculated with Freed theory. Under other conditions, both theories are consistent . Being a mean - field theory, Flory - Huggins theory can not give good results. For a ternary system, the coexisting regions calculated with the new model and Freed theory are very close to each other, but those calculated with Flory -Huggins theory are different. Besides, the new model can describe phase behavior with loop spinodals or binodals .