数值模拟气体分子在丁基橡胶中的渗透行为

Numerical Simulation Study on the Penetration of Gas Molecules in IIR

使用分子动力学和巨正则蒙特卡洛的方法,构建丁基橡胶(IIR)分子结构,计算模拟了H2、N2、O2、H2O、CO2、H2S、SO2在IIR中的溶解和扩散行为。结果表明:对气体分子的扩散而言,分子直径越小扩散系数越大;除H2O和H2S以外溶解系数随着分子直径的增大而增大;所得渗透系数的模拟值与实验值吻合度较高,这为提高材料的阻隔性能提供了一定理论基础,很好地从微观上解释了不同分子气体在硫化丁基橡胶中渗透的差异性和规律。

Molecular dynamics（MD）and grand canonical Monte Carlo（GCMC）method were used to study the diffusion and the solubility coefficients of H2,N2,O2,H2 O,CO2,H2 S,and SO2 in butyl rubber（IIR）.Using the free volume theory,the mechanism of the diffusion of small molecules in butyl rubber was discussed.The experimental results are shown that in terms of small gas molecules,the smaller the diameter and the faster the kinematic velocity,the higher the diffusion coefficient.The solubility coefficients of small gas molecules increased with the increasing of diameters except H2 O and H2 S.Moreover,the permeability coefficients obtained by the simulation were in good agreement with the experimental data,which provides some theoretical basis for improving the barrier properties of materials.