中文摘要：

将Sanchez-Lacombe状态方程与Vrentas-Duda模型相结合,提出改进的高分子-溶剂体系扩散系数模型。改进的模型利用高分子结构单元的范德华体积导出高分子自由体积分数表达式,仅利用状态方程的特征参数和高分子的玻璃化温度确定用于扩散过程的有效自由体积。与Vrentas-Duda模型相比,改进的模型避免进行高分子的粘弹性实验回归自由体积参数;与前期研究相比,计算过程避免查阅数据手册获得高分子热膨胀系数,因此模型的预测性增强。对4种溶剂在3种高分子中自扩散系数和互扩散系数的计算结果表明,改进的模型具有较好的预测精度。

英文摘要：

By combining the Sanchez-Lacombe equation-of-state （EOS） with the Vrentas-Duda model, a modified diffusion coefficient model of polymer-solvent systems was proposed. In this model, the expression of fractional free volume of the polymer was derived by the van der Waats volume of polymer structural units, and the effective free volume provided by the polymer was determined solely by characteristic parameters of the EOS and polymer glass transition temperature. Compared with the Vrentas-Duda model, measurements of polymer viscoelasticity were avoided. In addition, compared with our previous work, requirements of obtaining thermal expansion coefficients from polymer handbook were no longer needed. Therefore, the prediction capability of the modified model was improved. Calculated diffusion coefficient results of four solvents in three polymers indicated that, predictions of both solvent self- and mutual-diffusion coefficients by the modified model were generally consistent with experimental results.