采用分子动力学模拟技术研究聚乙烯/脲醛树脂复合材料中水分的扩散

Study on Moisture Diffusion in Polyethylene/Poly(urea-formaldehyde)Composites by Molecular Dynamics Simulation

以脲醛树脂(PUF)作为壁材,双环戊二烯(DCPD)作为芯材的微胶囊掺杂进聚乙烯(PE)材料,可实现材料的自修复功能,但掺杂微胶囊会影响PE材料的性能。采用分子动力学模拟技术设计了3个不同PUF浓度的PE/PUF掺杂模型和1个嵌入纳米SiO2的掺杂模型,经分子动力学计算分析其密度、自由体积分数,以及水分在材料内部的均方位移和扩散系数。结果表明:随着PUF掺杂浓度的增加,PE/PUF复合材料的密度逐渐增大,自由体积分数逐渐减小,且水分扩散逐渐加快;掺杂纳米SiO2可以抑制PE/PUF复合材料中水分的扩散。

Polyethylene(PE)material doped by the microcapsule with urea formaldehyde resin(PUF)as wall material and dicyclopentadiene(DCPD)as core material has self-healing function,but doping microcapsules will affect the performance of PE material.Three PE/PUF doping models with different PUF concentrations and a doping model embedded in nano-SiO2 were designed by the molecular dynamics simulation.The density,free volume fraction,and the mean square displacement as well as diffusion coefficient of H2O in material were calculated and analyzed by molecular dynamics.The results show that with the increase of PUF doping concentration,the density of the PE/PUF composites increases gradually,the free volume fraction decreases gradually,and the moisture diffusion accelerates gradually.The doping of nano-SiO2 can inhibit the moisture diffusion in PE/PUF composites.