用渗流理论计算高分子溶液中溶剂的自扩散系数

基于微观渗流理论建立了溶剂小分子在高分子溶液中的自扩散模型,并据此模型对不同温度和浓度下的聚苯乙烯(PS)-苯、PS-甲苯、PS-乙苯和PS-四氢呋喃4个体系中小分子的自扩散系数进行了关联,计算出在不同温度下溶剂分子扩散所需的临界浓度。结果表明,在PS玻璃化温度以下,本模型对于温度和浓度具有很好的适用性和关联精度。

Calculation of Solvent Self-diffusion Coefficient in Polymer Solution by Percolation Theory

According to the percolation theory, a new model which is used to describe the solvent self diffusion in polymer solution has been established. The solvent self diffusion coefficient of PS toluene, PS benzene, PS ethylbenzene and PS THF systems has been correlated by using the new model at different temperatures and concentrations and the critical volume fraction of solvent self diffusion at different temperatures has been estimated. The results show that below the glass temperature of PS, the new model not only has a satisfactory correlated accuracy, but it is suitable for a large range of temperature and concentration.