Research on Ba2Ti9O20-filled polybutadiene composites with near-zero temperature coefficient of dielectric constant by SiO2 addition.

A study on Ba₂Ti₉O₂₀ and SiO₂ ceramic powder-filled polybutadiene (PB) composite substrates was conducted in this paper. The total content of ceramic fillers was a fixed value of 85 wt.% and the SiO₂ content varied from 5 to 25 wt.%. The analyses of FTIR, XPS, TEM, Contact Angle testing, and SEM were performed to study the surface characteristics of Vinyltrimethoxysilane (A171)-modified Ba₂Ti₉O₂₀. The microstructure of composite substrates displayed that Ba₂Ti₉O₂₀ and SiO₂ ceramic fillers distributed in PB homogeneously with a small amount of SiO₂ addition. However, SiO₂ filler particles agglomerated and poorly dispersed in composites with 25 wt.% SiO₂ loading. Furthermore, the effects of SiO₂ filler loading on density, porosity, dielectric properties, and mechanical properties of composites were investigated in detail. Last, the composites exhibited medium dielectric constant (ε r = 7.32) , low dielectric loss (tan δ = 0.002), near-zero temperature coefficient of dielectric constant ( τ ε = - 8.07 ppm / ∘ C ) at a high frequency of 10 GHz, relatively low porosity (1.36%), and acceptable bending strength (75.26 MPa) at 65 wt.% Ba₂Ti₉O₂₀ and 20 wt.% SiO₂ fillers loading. [ABSTRACT FROM AUTHOR]