潮湿环境下金红石型纳米TiO_(2)掺杂聚乙烯的分子动力学模拟

Molecular dynamics simulation of rutile nano-TiO_(2)doped polyethylene under humid environment

为了从微观角度分析金红石型纳米TiO_(2)掺杂对聚乙烯(polyethylene,PE)材料性能的影响,采用分子动力学模拟方法,构建不同水分子质量分数的PE和TiO_(2)/PE复合模型,以温度为变量研究分析纳米TiO_(2)改性PE材料前后的热力学性能和微观结构以及水分子在复合体系中的扩散能力。结果表明:纳米TiO_(2)的掺杂使PE体系的玻璃化转变温度提高了33 K,杨氏模量提升了428.17%,剪切模量提升了338.62%。纳米TiO_(2)极大抑制了PE分子链的运动和水分子的扩散,增强了复合体系的稳定性。水分子的加入和温度的升高降低了复合体系的热力学性能,这两者均破坏了复合体系的稳定性。

In order to analyze the effects of rutile nano-TiO_(2)doping on the properties of polyethylene(PE)materials from the microscopic perspective,PE and TiO_(2)/PE composite models with different mass fractions of water molecular were constructed by using molecular dynamics simulation method.And then taking temperature as a variable,the thermodynamic properties and microstructure of PE before and after being modified by nano-TiO_(2)and the diffusion ability of water molecules in the composite system were analyzed.The results show that after doping with nano-TiO_(2),the glass transition temperature of PE system increases by 33 K,the Young's modulus increases by 428.17%,and the shear modulus increases by 338.62%.Nano-TiO_(2)greatly inhibits the movement of PE molecular chain and the diffusion of water molecules,which increases the stability of the composite system.The addition of water molecular and the increase of temperature decrease the thermodynamic properties of the composite system,both of which destroy the stability of the composite system.