水在环氧树脂中扩散的分子动力学模拟

Molecular dynamics simulation of water diffusion in epoxy resin

用分子动力学方法(MD)模拟水分子在TGDDM/DDS交联环氧树脂中的扩散,分析了温度和含水量对水在环氧聚合物中扩散系数的影响。基于Einstein公式,通过均方位移曲线计算的扩散系数表明,温度越高,水分子扩散系数越大,与文献中所给出的实验值相吻合:在含4个不同水浓度的环氧体系中,得到的水分子氧原子间的径向分布函数表明,含水量越高,存在于系统中的水越易以水分子簇形式存在。从微观上证实了模拟结果-扩散系数随水浓度的升高而增加,此结论也通过实验得到了证实。

The diffusion of water in crosslinked epoxy resin composed of tetraglycidyl-4,4＇-diamino diphenylmethane （TGDDM） and 4,4＇diamino diphenyl sulfone （DDS） was investigated by molecular dynamics （MD） simulation,the calculated diffusion coefficient based on Einstein equation revealed the effect of temperature and moisture concentration on the diffusion process of water molecules.The results showed that the higher the temperature,the faster the diffusion of water,which agreed well with the variation trend of experimental data given in literature.meanwhile,the radial distribution function between the oxygen atom of water molecules indicated that water prefered to the existence of water clusters with an increase in moisture concentration.This simulation study provided atomistic insight into the microscopic properties of polymer and confirmed the conclusion that the diffusion coefficient of water increased with total water content,consistented with experimental measurements.