聚乙烯/乙烯–醋酸乙烯酯共聚物界面相容性的分子动力学研究

Molecular Dynamics Study of the Interfacial Properties of Polyethylene and Ethylene-vinyl Acetate Copolymer Composites

为能够对交联聚乙烯电缆半导电屏蔽材料选型提供一定的参考意见,采用分子动力学方法研究了聚乙烯(PE)与乙烯–醋酸乙烯酯共聚物(EVA)界面相的结构、界面结合能。研究结果表明:醋酸乙烯酯(VA)摩尔分数的不同能够较为明显地影响到PE/EVA界面相的结构以及界面结合能,即随着VA摩尔分数从12%到40%变化,PE/EVA界面相的分子间径向分布函数逐渐变小,界面相中的原子数密度逐渐降低,界面结合能减小。因此,较低VA摩尔分数的EVA树脂更适合应用于交联聚乙烯电缆的内半导电屏蔽层;较高VA摩尔分数的EVA树脂更适合应用于交联聚乙烯电缆的外半导电屏蔽层。

A molecular dynamic method was used to investigate the interracial compatibility of polyethylene（PE）/ethylene-vinyl acetate copolymer（EVA） system so as to suggest the selection on the semiconductive shield materials. The results indicate that various amount of the vinyl acetate（VA） can result in different molecular structure and different interfacial bonding energy in the interphase. It is found that the value of the inter radial distribution function, the atom numerical density and the interfacial bonding energy of the PE/EVA decrease with the amount of VA changing from 12% to 40%. These results show that the EVA with low amount of VA is suitable to be used in the inner semiconductive shield layer, and the EVA with high amount of VA is suitable to be used in the outer semiconductive shield layer.