Study On Preparation And Properties Of High Thermal Conductivity Composites Based On Graphene

With the development of electronic components toward high integration and miniaturization,the heat flux in devices increases rapidly,and the problem of heat dissipation becomes increasingly prominent.Therefore,in order to ensure the stability and reliability of devices,higher requirements are put forward for the performance of electronic packaging materials.Low thermal resistance and high thermal conductivity packaging materials can effectively emit heat generated in the device in time.Commonly used electronic packaging materials are metal,ceramics and polymer materials.Polymer thermal conductive materials have attracted much attention because of their easy processing,low cost and light weight.However,the thermal conductivity of polymer material itself is poor,which can not meet the heat dissipation requirements of electronic equipment.The usual method of improving the thermal conductivity is to combine the polymer with thermal conductive fillers..In this work,graphene(MG)and boron nitride(BN)were added to epoxy resin and polyacrylic acid(PAA)to prepare MG/epoxy resin,MG@BN/PAA and MG@BN/epoxy resin,respectively.The contents of this paper mainly include the following parts:(1)In order to reduce the interfacial thermal resistance between MG and epoxy resin,we modified the surface of MG by attaching poly(3-hexythiophene)(P3HT)crystals to the surface of MG.The morphology of P3HT-MG composite filler was observed by high resolution transmission electron microscopy(HRTEM).The binding mode of P3HT and MG was confirmed by infrared absorption spectroscopy and Raman spectroscopy.The effects of the ratio of P3HT to MG and the content of P3HT@MG on the thermal conductivity of epoxy resin composites as well as the changes of the microstructure of the composites were studied in detail,and the corresponding theoretical models were put forward.(2)MG@BN/PAA composite thermal conductive material was prepared by solution precipitation method with MG and BN as composite fillers.The effects of the content of each component(MG,BN and PAA)on the thermal conductivity and electrical properties of the composites were studied in detail.The thermal conductivity mechanism of the composites was discussedconsidering the changes of the micro-morphology observed by SEM.It is found that MG@BN/PAA composite is not only high thermal conductive but also self-healable.(3)Based on the preparation of MG@BN/PAA thermal conductive material,firstly,P3HT-MG@BN/PAA gel-like composite was prepared,and then calcined at high temperature in inert atmosphereto make the PAA component be removed.The porous structure with P3HT@MG and BN as skeleton was obtained.Under vacuum,the porous epoxy resin was poured into the porous skeleton to prepare P3HT@MG/BN/epoxy thermal conductive material.The effects of the proportion and content of each component on the thermal conductivity and electrical properties of composite thermal conductive materials were analyzed in detail.