Study On Preparation And Thermal Conductivity Of Epoxy Based Composites

With the developing of electronic technology and the continuous improvement of our livelihood,much attention to food safety has reached a new height,all kinds of electronic products and electronic equipment for food testing and packaging are constantly being updated to adapt higher accuracy operating range,faster operating speed and smaller operating space to meet the need of industrial production and our increasing food safety requirements.Meanwhile,the continuous development and progress of the internet and communications industries have made electronic products more and more widely used in people's daily lives,bringing great convenience to our daily lives.However,the electronic components running inside are gradually transformed from isolate to highly integrated and tended to miniaturize.The huge heat generated by these components during work will seriously affect their high-efficient operation.Therefore,the development of packaging materials with high heat dissipation performance has become the main research direction in the field of electronics.Epoxy Resin(EP)has been widely utilized in the fabrication of heat-dispassion materials owing to their light weight,low cost,safety,easy-processing,outstanding electrically insulating and mechanical properties.However,EP matrix possesses low intrinsic thermal conductivity(0.1-0.5Wm-1K-1),significantly limiting the application in electric packaging.Consequently,how to improve the thermal conductivity of EP to expand its wide application in the field of heat dissipation has become the focus and difficulty of current research.In this work,boron nitride(BN)and aluminum nitride(AlN)were used as thermally conductive fillers to prepare filled epoxy resin thermal conductive composite materials,and the effects of filler type,content,hybrid filler with different particle size mixing and surface modification on the thermal conductivity,thermal stability,electrical insulation,and dielectric properties of composite materials were investigated,as follows.Firstly,two single filler BN/EP and AlN/EP composites and hybrid BN-AlN/EP composites were fabricated by the solution mixing and hot-press method.The results show that the thermal conductivity of the composites increases with the filler content increasing,and there is a synergetic effect between hybrid filler composites.The thermal conductivity of BN-AlN/EP composite can reach 2.4 Wm-1K-1 with 40 vol%filler content,which is nearly twice that of two single filler composites.At the same time,the Y.Agari model were used to simulate and theoretically predict the thermal conductivity of the three composite materials,and analyzed the different capabilities of forming the thermal network chain for various composites.It was found that the simulated value of BN-AlN/EP hybrid composite material is closest to the experimental value in the three composite material systems,and theoretically confirmed that the hybrid filler can form a richer thermal conductivity network than that of two single fillers in the composites.Secondly,both BN and AlN were modified by silane coupling agent KH550.The morphological changes and dispersion of the thermally conductive particles via modification and their influence on the properties of the composite were investigated.The results show that the addition of M-(BN-AlN)filler promotes the dispersion of the filler in the matrix and improves the interfacial bonding between filler and matrix,which significantly promotes the phonon transformation between filler and matrix.When 40 vol%M-(BN-AIN)was added,the thermal conductivity of M-(BN-AlN)/EP composites can reach 2.6 Wm-1K-1,which is 10%higher than unmodified hybrid composites at the same content.In addition,thermal infrared imaging technology was also used to intuitively research the heat propagation behavior in the composite material,and the results are consistent with the thermal conductivity of the corresponding material.Finally,the effects on the thermal conductivity of the BN-AlN/EP composites with various AlN particle were also studied.It was found that the thermal conductivity of different particle size BN-AlN/EP composites is also related to filler content.Before 30 vol%total filler content,the smaller the AlN particle size,the higher the thermal conductivity of the BN-AlN/EP composite.After 30 vol%total filler content,the larger the AlN particle size,the higher the thermal conductivity of BN-AlN/EP composite.When 40 vol%10 ?m AlN hybrid filler is added,the thermal conductivity of the BN-AlN/EP composite can reach up to 2.7 Wm-1K-1,which is higher than that of the other two particle size hybrid composites.This is highly consistent with the thermal infrared test results,while maintaining excellent dielectric and electrical insulation properties.This study provides theoretical guidance and practical application value for the preparation of composite materials with high thermal conductivity.