混合气体在聚合物注射成型保压阶段中扩散的分子动力学模拟

构建了含有氧气、氮气分子和聚合物聚甲基丙烯酸甲酯（PMMA）高分子链的单元模型，并通过能量优化、退火等处理使其接近保压阶段状态，然后改变温度或压力进行分子动力学模拟，探讨微观尺度下混合气体（氧气和氮气）在聚合物PMMA中扩散的情况；并探讨了混合气体分子间相互作用的影响。模拟结果表明,随着温度或压力的增加，氧气和氮气在PMMA内的扩散系数增大；当温度或压力增大到一定程度时，扩散系数几乎不变，逐渐达到扩散平衡;模拟过程中发现气体分子在聚合物中的扩散过程中具有协同效应，混合气体的扩散系数大于纯气体的扩散系数。

Molecular Simulation of Mixed Gas Diffusion in Packing Stage in Polymer Injection Molding Process

A model was formulated that contained oxygen, nitrogen molecules and PMMA polymer chains. The diffusion of the mixed gas (oxygen and nitrogen) in PMMA was simulated at different temperatures or pressures. It was found that the diffusion coefficients of oxygen and nitrogen in PMMA increased with increasing temperature and pressure and finally reached a platform. The interaction between the two kinds of molecules during the diffusion was also discussed. Different kinds of molecules had a synergistic effect during the diffusion, the diffusion coefficient of the gas in the mixed gas system was greater than that in the pure gas system.