Performance improvement of alumina/silicone rubber composites by adding 3‐(trimethoxysilyl)propyl methacrylate grafted siloxane copolymer

Abstract 3‐(Trimethoxysilyl)propyl methacrylate grafted poly(methylhydrosiloxane‐co‐dimethylsiloxane) (MPS‐g‐PHMS‐PDMS) was synthesized by hydrosilylation reaction. MPS‐g‐PHMS‐PDMS was used as a modifier and directly added into silicone rubber compounds. The effect of MPS‐g‐PHMS‐PDMS on the properties of alumina/silicone rubber composites was studied. The addition of MPS‐g‐PHMS‐PDMS increased the bound rubber content of alumina/silicone rubber compounds and the crosslink density of alumina/silicone rubber composites, indicating the enhancement of filler‐rubber interaction. SEM images indicated that MPS‐g‐PHMS‐PDMS could promote the uniform dispersion of alumina in the composites and decrease the filler‐rubber interface defects. The alumina/MPS‐g‐PHMS‐PDMS/silicone rubber (500/10/90) composite had the thermal conductivity of 1.68 W/(m∙K) and the tensile strength of 3.17 MPa, exhibiting 18.3% and 84.3% enhancement compared with the alumina/silicone rubber (500/100) composite. This work provides an insight for enhancing thermal conductivity and tensile strength of silicone rubber composites at a high filler content.