Study On The Preparation And Performances Of Thermal Conductive Silicone Rubber

With the rapid development of integrated circuit technology in the fields of automobile,aerospace,weapon equipment and communication,miniaturization and integration of microelectronic devices have put forward higher requirements for thermal conductivity and mechanical properties of Thermal Interface Materials(TIM).At present,most of the Thermal Interface Materials are filled polymer composites,whose qualities are limited by the properties of polymer materials,and it is difficult to meet the heat dissipation requirements and the complex process.However,RTV silicone rubber is a substrate material with excellent thermal stability,elasticity and electrical insulation,which can be vulcanized naturally at room temperature.The purpose of this paper was to prepare thermal conductive silicone rubber with high thermal conductivity and high elasticity.In this paper,Al₂O₃ and Si C were selected as thermal conductive fillers to be filled into silicone rubber,and the influence of factors such as filler quantity,surface modification and particle size on thermal conductivity and mechanical properties of thermal conductive silicone rubber were investigated.In addition,this paper also proposed the random distribution model of thermal conductive silicone rubber with particles.The thermal conductivity of the model was solved by Digimat modeling software and ANSYS simulation software,and the correctness of the model was verified by comparing with the experimental data and the theoretical values of Maxwell model.The results showed that the thermal conductivity,hardness and tensile strength of thermal conductive silicone rubber increased with the increase of the filling amount,and the breaking elongation first increased and then decreased.With the increase of the particle size of the filler,the thermal conductivity of the thermal conductive silicone rubber increases,and the hardness and tensile strength decrease.The surface modification of filler can improve the thermal conductivity of heat-conducting silicone rubber to some extent.The effect of particle size matching with thermal conductivity of silicone rubber was not obvious.An appropriate amount of reinforcing agent can enhance the activity of silicone rubber and improve the hardness of thermal conductive silicone rubber.The thermal conductivity of Al₂O₃ thermal conductive silicone rubber reached the highest value of 1.43 W/(m?K)and the hardness was 47 HA.The thermal conductivity of Si C thermal conductive silicone rubber reached the highest value of 1.68 W/(m?K)and the hardness was 46 HA,which all met the requirements of thermal interface materials.In the finite element numerical simulation analysis of thermal conductive silicone rubber,the particles random distribution heat conduction model was put forward.It was found that the numerical simulation results were deviated from the theoretical values of Maxwell model under the condition of high filling quantity,and the numerical simulation results fit well with the experimental data,so as to verify the correctness of the thermal conductivity model.