表面接枝KH550的石墨烯改性聚二甲基硅氧烷热力学性能的分子动力学模拟  

Molecular Dynamics Simulation of Thermodynamic Properties of Polydimethylsiloxane Modified by KH550-grafted Graphene

作　　者：李亚莎[1] 田泽 王璐敏 庞梦昊 曾跃凯 赵光辉 LI Yasha;TIAN Ze;WANG Lumin;PANG Menghao;ZENG Yuekai;ZHAO Guanghui(School of Electrical and New Energy,China Three Gorges University,Yichang 443002,Hubei,China)

机构地区：[1]三峡大学电气与新能源学院,湖北宜昌443002

出　　处：《材料导报》2025年第2期257-262,共6页Materials Reports

基　　金：国家自然科学基金(51577105)。

摘　　要：为分析表面接枝有硅烷偶联剂KH550的石墨烯对聚二甲基硅氧烷(PDMS)性能的影响,本工作采用分子动力学的方法对纯PDMS、未接枝KH550的石墨烯改性PDMS,以及表面接枝KH550的石墨烯(接枝密度分别为6%和12%)改性PDMS进行建模,从微观角度对比分析改性后PDMS热力学性能的提升。模拟结果表明,在PDMS中掺杂石墨烯或在石墨烯表面接枝KH550后再与PDMS混合,均能改善PDMS热导率、玻璃化转变温度、自由体积、均方位移及水分子的扩散系数和结合能等热力学性能。在含水模型中,接枝密度为6%和12%的表面接枝KH550石墨烯改性PDMS相较于纯PDMS 250 K热导率分别提高25.6%和21.6%,玻璃化转变温度分别提高70 K和77 K。对比接枝KH550的石墨烯改性PDMS的含水与不含水的模型可知,水分子能够提高均方位移,降低玻璃化转变温度和减小自由体积,同时水分子扩散系数及结合能随温度与接枝密度的不同而有所差异。本研究的结果可为减少冰闪电压对电力系统影响的实验研究提供参考,同时对研发输电线路融冰、疏水性材料提供理论支撑。The present work focused on the effects of silane coupling agent-grafted graphene on the properties of polydimethylsiloxane(PDMS),and carried out molecular dynamics modelling and simulation for pure PDMS,PDMS modified by non-grafted graphene,and PDMS modified by KH550-grafted graphene(with graft intensities of 6%and 12%),in order to analyze the thermodynamic property improvement induced by modification.The simulation indicated that either non-grafted graphene or KH550-grafted graphene has positive influence on thermodynamic properties of PDMS such as thermal conductivity,glass transition temperature(Tg),free volume,mean square displacement,and water molecules’diffusion coefficient and H2 O-composite binding energy.In the water-containing models,6%and 12%KH550-grafted graphene modified PDMSs could achieve improvements in thermal conductivity(at 250 K)of 25.6%and 21.6%,respectively,and Tg rises of 70 K and 77 K,respectively,compared with pure PDMS.The comparison between the water-containing and non-water models of the KH550-grafted graphene modified PDMS confirmed that water molecules results in increase in mean square displacement,and reductions in Tg and free volume,and the H2 O molecule diffusion coefficient and H2 O-composite binding energy differs with varying temperature and graft intensity.The output of this work may provide useful information for future studies on mitigating the impact of flashover voltage on electric system,and theoretical support for the development of transmission line de-icing and hydrophobic materials.

关 键 词：聚二甲基硅氧烷(PDMS) 硅烷偶联剂 KH550 热导率 扩散系数 分子动力学模拟 

分 类 号：TM211[一般工业技术—材料科学与工程] TB35[电气工程—电工理论与新技术]