Investigation of TiO2 and SiO2 Filled Polybutadiene Composite Substrates and Their Dielectric Properties

Abstract Polybutadiene‐based (PB) composite substrates filled with TiO 2 and SiO 2 ceramics were fabricated in this work. The total content of ceramic components modified by vinyltrimethoxysilane (A171) was fixed at 80 wt.% with TiO 2 amount varying from zero to 8 wt.%. The differences of characteristics of ceramic fillers before and after surface modification were analyzed comprehensively and the treated ceramic fillers were uniformly distributed in the polymer matrix. The effects of TiO 2 filler addition on the performances of SiO 2 /PB composite substrates, such as microstructure, moisture absorption, dielectric and thermal properties were also systematically studied. The composite filled with 4 wt.% TiO 2 and 76 wt.% SiO 2 exhibited excellent dielectric properties with proper dielectric constant ( ϵ r =3.2), ultra‐low dielectric loss ( tanδ =0.0017) at 10 GHz and a near‐zero τ ϵ (0.5 ppm/°C) was obtained at filler content of 8 wt.% TiO 2 and 72 wt.% SiO 2 .