氢及其同位素在溴化丁基橡胶中渗透的分子模拟

使用分子动力学(MD)和巨正则蒙特卡罗(GCMC)的方法,对H_2,D_2,T_2在溴化丁基橡胶(BIIR)中的扩散和溶解行为进行了计算模拟,运用自由体积理论探讨了气体分子在聚合物内的扩散机理,并得出气体的运动轨迹。结果表明:对氢及其同位素而言,质量越小,运动速度越快,扩散系数越大,溶解度系数比较接近,渗透系数的模拟值与实验值基本吻合,为提高材料的阻隔性能提供了一定理论基础,同时预测出硫化溴化丁基橡胶对氚水也有较好的阻隔性能。

Molecular simulation of transport behavior of hydrogen and hydrogen isotopes in brominated butyl rubber

Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) method were used to study the diffusion and the solubility coefficients of H2, D2, T2 in brominated butyl rubber (BIIR). Using the free volume theory, the mechanism of the diffusion of small molecules in brominated butyl rubber was discussed, and the trajectory of gas motion was obtained. It was shown that in terms of hydrogen and hydrogen isotopes, the smaller the mass was and the faster the kinematic velocity was, the higher the diffusion coefficient was. The solubility coefficients of H2, D2, T2 were close. Moreover, the permeability coefficients obtained by the simulation were in good agreement with the experimental data. They provided some theoretical basis for improving the barrier properties of materials, simultaneously the fact that tritium also had good barrier properties to vulcanized brominated butyl rubber was forcasted.