Improving thermal and mechanical properties of the alumina filled silicone rubber composite by incorporating carbon nanotubes

Abstract Carbon nanotubes (CNTs) can be used to improve the thermal and mechanical properties of composites owing to their excellent characteristics. Methyl vinyl silicone rubber matrix composites filled with alumina (Al2O3) powder and CNTs were fabricated through a conventional mechanical blending method. The effects of the mass fraction, surface modification of Al2O3 powder and the addition of CNTs on the thermal conductivity, Young's modulus and hardness of the composites were investigated. Results show that a higher mass fraction of the Al2O3 powder results in a higher thermal conductivity of the composites. When the mass fraction of Al2O3 powder is fixed, the thermal conductivity, Young's modulus and hardness of the composites are improved obviously by surface modification of Al2O3 powder and adding a small amount of CNTs. The combination of the modified Al2O3 filler and CNTs filler can synergistically enhance the interfacial interaction between the fillers and rubber matrix by the formation of better heat conduction channels and network structures in the rubber matrix, thereby improving the thermal conductivity and mechanical properties of the composites.