纳米SiO2掺杂对高交联度环氧树脂热力学性能影响的分子动力学模拟  

Molecular Dynamics Simulation of the Influence of Nano-SiO2 Filling on Thermo-mechanical Properties of Highly Cross-linked Epoxy Resin

作　　者：谢庆[1] 段祺君 张磊[1] 赵云晓 陆路[1] 黄正勇[2] XIE Qing;DUAN Qijun;ZHANG Lei;ZHAO Yunxiao;LU Lu;HUANG Zhengyong(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Baoding 071003,China;State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,保定071003 [2]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044

出　　处：《高电压技术》2020年第5期1602-1611,共10页High Voltage Engineering

基　　金：国家重点研发计划(2017YFB0903800);中央高校基本科研业务费专项资金(2019MS083)。

摘　　要：为从微观角度分析纳米SiO2掺杂对环氧复合材料性能的影响,以双酚A二缩水甘油醚(DGEBA)、甲基四氢苯二甲酸酐(MTHPA)分别作为环氧树脂基体和固化剂,基于分子动力学(molecular dynamics,MD)的方法建立了高交联度90%的纯环氧树脂和粒径为1.5 nm、2.0 nm的SiO2/EP复合模型,分析纳米SiO2掺杂对环氧复合材料的微观结构影响及热力学性能的提升效果,并且对比纳米SiO2粒径大小对材料性能提升的影响。研究发现,纳米SiO2的掺杂能提高环氧复合材料的热力学性能,粒径1.5 nm的纳米SiO2对环氧复合材料的提升效果更加显著。其中,掺杂粒径1.5 nm的纳米SiO2对环氧复合材料玻璃化转变温度的提升幅度为29.78 K,杨氏模量提高16.83%,剪切模量提高6.02%,体积模量提高4.20%。同时,纳米SiO2的掺杂改变了环氧复合材料的微观结构参数,内聚能密度有明显的提高,自由体积占比和均方位移均有不同程度的降低,粒径为1.5 nm的纳米SiO2对材料的微观结构影响更明显;但纳米SiO2的掺杂并未明显改变复合材料的全原子的径向分布函数。In order to analyze the effects of nano-SiO2 filling on the properties of epoxy resin on a micro level,DGEBA and MTHPA were used as epoxy resin matrix and curing agent,respectively,and a composite model of high crosslinking degree of 90%of pure EP and SiO2/EP with particle sizes of 1.5 nm and 2.0 nm was established based on molecular dynamics.Then the effects of nano-SiO2 filling on the microstructure of epoxy composites and the improvement of thermomechanical properties were analyzed,and the effect of nano-SiO2 particle size on the performance improvement was compared.The results show that the thermomechanical properties of epoxy resin are improved by the addition of nano-SiO2,and the improvement of nano-SiO2 with a particle size of 1.5 nm is more significant.Specially,the nano-SiO2 with particle size of 1.5 nm increases the glass transition temperature by 29.78 K,and the increases of Young’s modulus,shear modulus,and bulk modulus are 16.83%,6.02%and 4.20%,respectively.At the same time,the filling of nano-SiO2 changes the microstructural parameters of the epoxy composites,the cohesive energy density is enhanced significantly after filling nano-SiO2,and the fractional free volume and the mean square displacement decrease to variousg degrees.In addition,the nano-SiO2 with particle size of 1.5 nm has a more obvious effect on the microstructure of the composites.However,the filling of nano-SiO2 does not significantly change the total radial distribution function for the 90%crosslinked system.

关 键 词：环氧树脂 纳米SiO2掺杂 绝缘材料 热力学性能 分子动力学 

分 类 号：TB332[一般工业技术—材料科学与工程]