Preparation And Thermal Properties Of Flake Graphite And Graphene-based Thermal Interface Materials

With the advent of the 5G era,the power consumption and frequency of electronic devices have gradually increased,leading to a sharp increase in heat generation,which has brought great challenges to the thermal stability of electronic devices.Therefore,the role of thermal interface materials in electronic devices has become increasingly prominent,and high-performance thermal interface materials will be added to the design of electronic products to speed up the heat dissipation of electronic products and extend their service life.Traditional thermal interface materials are generally composed of polymers and thermally conductive fillers.Common thermally conductive fillers include metal nanoparticles,ceramic materials,and carbon nanomaterials.The carbon material unit has excellent mechanical and thermal conductivity properties.Graphite derivatives are obtained through structural optimization.Reducing the filler dimension can reduce the interface effect and improve the heat transfer performance.Carbon or its derivatives combined with the elastic matrix can be mechanically oriented to prepare high thermal conductivity stretchable oriented thermal interface material.This paper mainly studies the interaction mechanism between flake graphite or graphene and the thermoplastic elastomer-hydrogenated styrene-butadiene block copolymer(SEBS)and optimizes the preparation process of graphite oxide as the precursor for obtaining graphene.The process summarizes the effect of filler content on the thermal conductivity and mechanical properties of composite materials,analyzes the actual application of thermal interface materials,and then summarizes the process parameters for the preparation of better stretchable oriented thermal interface materials.The results show that the use of the anisotropy of flake graphite can give the composite material a higher degree of orientation through mechanical methods such as scraping and hot pressing so that the SEBS/flake graphite composite thermal interface material has a higher out-of-plane thermal conductivity of 10.08 W/(m k);By controlling the mass ratio of flake graphite to the matrix,the balance point between the thermal conductivity and mechanical properties of the composite material was found,so that the SEBS/flake graphite thermal interface material not only has a higher out-of-plane thermal conductivity but also has considerable stretchable properties,which elongation at break is 63%.Capturing the characteristics of graphene's high thermal conductivity and excellent toughness,using the improved Hummers method to prepare reduced graphene oxide,optimizing the process of preparing graphite oxide,preparing SEBS/graphene composite thermal interface materials,and obtaining higher out-of-plane thermal conductivity 16.81 W/(m k)thermal interface material.According to the thermal resistance test,the SEBS/flake graphite composite thermal interface material has a lower thermal resistance value of 2.45×10^-4K·m²/W when the filler content is 50wt%;According to the thermal infrared image,the excellent actual heat dissipation ability of the composite thermal interface material is obtained;According to the thermal cycle stability test,the reliability of SEBS/flake graphite composite thermal interface material in the practical application was analyzed.