Simultaneously enhance thermal conductive property and mechanical properties of silicon rubber composites by introducing ultrafine Al2O3 nanospheres prepared via thermal plasma

It is great significant to develop polymer composites with high thermal conductivity and excellent mechanical properties simultaneously. Generally, a high loading of fillers is required for thermal conductive composites. However, traditional polymer composites exhibit unsatisfactory enhancement due to poor dispersion and weak interfacial adhesion, for which lead to high interfacial resistance. Meanwhile, the mechanical properties of composites are greatly damaged because of internal defects caused by imperfect filling. Herein, Al2O3 nano spheres prepared by high frequency thermal plasma are first used as filler to increase thermal conductivity of silicon rubber (SR) and reinforce the mechanical properties of SR. The Al2O3 nanospheres show good compatibility and strong interfacial adhesion with matrix. Thus SR composites exhibit excellent thermal conductivity of 1.53 Wm(-1)K(-1), corresponding to an enhancement of 665% compared to SR. Importantly, the SR composites still possess high tensile strength of 5.71 MPa, modulus of 9.69 MPa and fracture toughness of 1.81 MJ/m(3) respectively, improving by 1630%, 3360% and 723% compared with neat SR. In addition, The Al2O3/SR composites also possess good dielectric properties, high volume resistivity and enhanced thermal stability, indicating a promising application of composites in the field of electronic packing. Therefore, this work offers a novel route to design high performance SR composites using Al2O3 nanospheres prepared by thermal plasma.