Preparation Of High Thermal Conductivity And Insulating Polymer Matrix Composites

With the rapid development of the electronics industry,it’s difficult for the traditional thermal conductivity materials to meet the demand for corrosion resistance and insulation.Although polymers have many excellent properties,such as insulation,processability and corrosion resistance.The thermal conductivity of the polymer is usually low.Therefore,it’s urgent to develop a new material with high thermal conductivity.In this work,two different systems were selected to discuss the main factors to influence the thermally conductivity.One is epoxy resin system,the other is silicone system.The thermal conductive particles of SiC,Al2O3 and AlN were employed to improve the responding thermally conductivity.The effects of particle size and structure on the thermal behavior were also studied.Laser method and steady state heat flow method were used to determine the thermal conductivity of the composites.Compared with the normal materials(the internal structure of the materials are the same)and composite materials(the internal structure of the materials are different),we found that the thermal conductivity of the composites was closely related to its thickness.Because of the internal resistance between the resin and particles,the thickness of the composites had a great effect on the thermal conductivity of the composites.Furthermore,the efficient heat transfer network also had a great positive effect on improving the thermal conductivity of the composites.In the epoxy resin system,we proposed to choose the appropriate thermal particles according to the size of the sample to build a "through-type" structure of thermal network.We used Agari equation to verify the effect of the "through type" structure.The experimental results indicated that the "through-type" structure could effectively improve the thermal conductivity of the composite material.Depending on the combination of SiC particles with different particle size,its thermal conductivity could reach 24 W/(m·K),which was 120 times higher than that of epoxy resin.In the silica gel system,after the optimization of preparation and composition,the thermal conductivity of the silicone gasket was increased from 3.45 W/(m·K)to 4.6 W/(m·K).Moreover,the "through-type" structure could still improve the thermal conductivity of the composites in the silica gel system.In the silica gel system,we selected filler particles according to the target sample size to build a perfect "through-type" thermal network and the thermal conductivity of silicone gasket reached 5.7 W/(m·K).