Computational Simulation Study On Interfacial Thermal Resistance Of Graphene/PA56 Composites

Polymers and polymer composites are widely used in structural materials and electronic products due to their versatile functions,light weight,low cost,and excellent chemical stability.However,the thermal conductivity of polymers is usually very low,between 0.1 W / m K and 0.6 W / m K,and their low thermal conductivity limits their application in certain fields,for example,the low thermal conductivity of polymers It may become one of the main technical barriers for polymer-based flexible electronic products.However,if a polymer with a high thermal conductivity can be designed,a polymer radiator and heat exchanger with compact structure,light weight,corrosion resistance,easy processing,and low cost can be manufactured,which in turn can promote electronic,Development of aviation and energy industries.Therefore,improving the thermal conductivity of polymers and polymer composites is of great significance.In this paper,three ways to reduce the thermal resistance of the interface are studied by molecular dynamics(MD)method:(1)Modifying graphene through chemical groups.The effects of Graphene/PA56 nanocomposites modified with different chemical groups and modified densities on the interfacial thermal resistance of the composites were studied.The results show that the chemical group modification can reduce the interface thermal resistance of the Graphene/PA56 composite,and the chemical group that can form a hydrogen bond with the PA56 matrix reduces the interface thermal resistance better.This is because the interaction of hydrogen bonding enhances the interaction between the matrix and the filler,thereby reducing the interface thermal resistance.(2)Modify graphene by grafting polymer chains.The polymer chains were grafted on the graphene surface,and the effects of the graft chain type,graft chain length and graft density on the interface thermal resistance of Graphene/PA56 nanocomposites were studied.The results show that: the greater the graft density,the longer the graft chain,the better the effect of reducing the interface thermal resistance;the graft chain PVA,which can form a strong interaction with the matrix,has a better effect of reducing the interface thermal resistance.(3)Form a conjugated structure on the graphene surface by hydrogen bonding to reduce the interface thermal resistance of the composite material.A transition layer is introduced between the PA56 matrix and the modified graphene filler to reduce the interface thermal resistance.This transition layer is composed of PA4-PA56 block copolymer,and the change of interface thermal resistance is observed by adjusting the proportion of PA4 adsorbed on the surface of modified graphene.The results show that the greater the proportion of PA4 adsorbed on the surface of the modified graphene,the smaller the interface thermal resistance of the composite material.