The Preparation And Properties Of VO₂@hBN Composite Phase Change Materials

With the rapid development of the electronics industry,the miniaturization,integration and multi-function of electronic devices,as well as the increase of package density,the heat dissipation problem of chips and devices is more and more serious and urgent need to be solved.This factor directly affects the efficiency and service life of chips and devices.Therefore,how to efficiently dissipate heat has become a key scientific and technical problem to be solved in the development of high-end electronic devices.Thermal interface materials are g enerally composed of silica gel,epoxy resin and other polymer matrix and alumina,silicon carbide,graphene,boron nitride and other thermal conductive fillers,with a certain degree of flexibility,mechanical strength and high thermal conductivity.In this paper,vanadium dioxide,a kind of hydrophilic phase change material,was grown onto the hexagonal boron nitride nanostructure and assembled into multistage nanomaterials VO₂@h BN,which can improved the dispersion stability of hexagonal boron nitride filler and contributed to improving the flexibility and mechanical properties of thermal interface materials.The following research results were obtained:（1）VO₂@h BN composite materials were prepared by hydrothermal method with different raw materials ratio of vanadium dioxide and hexagonal boron nitride,and VO₂@h BN-epoxy resin composites with different raw materials ratio were prepared by high-speed mixing mechanism.The optimal raw material ratio was determined by testing its thermal conductivity.The optimal raw material ratio provided f or the subsequent work was vanadium dioxide:hexagonal boron nitride=1:4.And make a series of representations.（2）Ice-VO₂@h BN-epoxy resin composite thermal conductive phase change material with a certain ordered structure was prepared by ice template method using the best raw material.When the filling rate of the filler is 12.40%,it can still show good thermal conductivity.（3）Hexagonal boron nitride was modified by high-speed ball mill and thermal method,and then modified-vanadium dioxide@hexagonal boron nitride-epoxy resin composite thermal conductive phase change material was prepared by high-speed mixing mechanism with the best raw material ratio.The dispersion and thermal conductivity of the modified composites in the polymer matrix are improved.