We propose a model based on non-equilibrium lattice fluid (NELF) theory and corrected fractional free volume of polymers to effectively and accurately predict the solubility of gases in different polymers. The method to achieve this purpose is based on the utilization of NELF model infinite dilution solubility coefficient (S0) as the base of predictive calculations. To account for the isolated pore in the polymer matrix in density estimation, a fractional free volume correction factor (β) was introduced in NELF model. The modified NELF model was successfully applied for prediction of solubility of C3H8 and CO2 in polyethylene oxide (PEO) and CO2 in polyethylene terephthalate (PET), isotactic polypropylene (i-PP), polyetherimide (PEI), polymethyl methacrylate (PMMA) and polyethyl methacrylate (PEMA) with adjustments in β value and depth of diffusion of gases in polymer matrix (ζ) at different pressures and temperatures. This work involves multi-objective optimization using genetic algorithm of MATLAB toolbox with adjusted settings. It applies to find the optimum temperature at which the minimum standard deviation of β for different gas-polymer systems is obtained. β showed the same trend of change with temperature as the constrained pressure imposed on the amorphous phase in semi-crystalline polymers. A cubic correlation for standard deviation for β versus temperature was obtained which was able to anticipate the changing trend of β at different temperatures. The chi-square test results verified that compared with original NELF model, a more accurate model for prediction of gas solubilities in polymers has been proposed.

中文翻译：

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基于修正的聚合物自由体积分数的修正非平衡晶格流体模型用于气体溶解度预测

我们提出了一个基于非平衡晶格流体 (NELF) 理论和校正的聚合物自由体积分数的模型，以有效准确地预测气体在不同聚合物中的溶解度。实现这一目的的方法是基于利用NELF模型无限稀释溶解度系数（S0）作为预测计算的基础。为了在密度估计中考虑聚合物基质中的孤立孔，在 NELF 模型中引入了分数自由体积校正因子 (β)。改进的 NELF 模型成功应用于预测 C3H8 和 CO2 在聚环氧乙烷 (PEO) 中的溶解度和 CO2 在聚对苯二甲酸乙二醇酯 (PET)、全同聚丙烯 (i-PP)、聚醚酰亚胺 (PEI)、聚甲基丙烯酸甲酯 (PMMA) 和聚甲基丙烯酸乙酯 (PEMA)，在不同压力和温度下调整 β 值和聚合物基体 (ζ) 中气体的扩散深度。这项工作涉及使用具有调整设置的 MATLAB 工具箱的遗传算法进行多目标优化。它适用于找到获得不同气体-聚合物系统的最小标准偏差 β 的最佳温度。β 显示出与施加在半结晶聚合物中的非晶相上的约束压力相同的随温度变化的趋势。获得了 β 与温度的标准偏差的三次相关性，它能够预测不同温度下 β 的变化趋势。卡方检验结果验证，与原始 NELF 模型相比，