Synchronous improvement in mechanical properties and dielectric performance of poly(silylene arylether arylacetylene) by introducing trifluoromethyl groups

Abstract

Poly(silylene arylether arylacetylene) (PSEA) resin is a promising material for preparing an advanced wave-transparent composite because of excellent thermal stability and good dielectric properties. Herein, a novel poly(silylene arylether arylacetylene) resin with trifluoromethyl groups (PSEAF) was synthesized by Grignard coupling reaction, and the effects of the incorporation of trifluoromethyl groups on various properties of PSEAF resin and quartz fiber reinforced composites were investigated. Compared to PSEA, the PSEAF resin exhibits better solubility and processability, and lower apparent activation energy for curing reactions. After thermal curing reactions, the PSEAF resin converts to an amorphous crosslinked network with the temperature at 5% weight loss (T_d5) around 470 °C. The cured PSEAF resin possesses improved mechanical properties and dielectric properties. The flexural strength arrives at 64.4 MPa, and the dielectric constant (ε) and dielectric loss (tanδ) at 30 MHz are 2.75 and 4.3 × 10⁻³, respectively. Besides, the quartz fiber reinforced PSEAF composite simultaneously shows ε of 3.3, theoretical wave transmittance |T|² of 91.4% at 7 GHz, and flexural strength of 350 MPa.