A novel thermosetting composite with excellent high-frequency dielectric properties and ultra-high-temperature resistance

0.8MgTiO₃ − 0.2(Ca_0.7La_0.2)TiO₃ (MTCLT) ceramic fillers with excellent microwave dielectric properties have been incorporated in a novel polysilylaryl-enyne (PSAE) resin with low dielectric loss to prepare PSAE/MTCLT composite. A unique process free of organic solvent has been employed to fabricate the composite. The results showed that highly dense and homogeneous microstructure was observed in all the composites with different filler volume fractions. With the increase in MTCLT volume fraction, the dielectric constant of the composite increased significantly from 2.8 to 10.0, while the dielectric loss decreased from 0.0056 to 0.0030 at 10 GHz. The coefficient of thermal expansion (CTE) of the composite could be reduced to less than 20 ppm/°C when 40 V% MTCLT ceramic was loaded which achieved a good match with copper foil. TGA and DMA results showed that the composite possessed excellent temperature resistance with the temperature at 5% mass loss (T_d5)> 850 °C and glass transition temperature (T_g) > 400 °C at N₂ atmosphere. The novel thermosetting PSAE/MTCLT composite reported in this work has good application prospects in high-power integrated circuits and some high-temperature-resistant environments.