Intrinsic low dielectric thermally crosslinked fluorinated polystyrene siloxanes at high frequency with good thermostability and optical properties

Three silicone monomers were prepared by Piers-Rubinsztajn reaction which catalyzed condensation reaction of hydrosilane and alkoxysilane under mild conditions. Due to the thermo-crosslink reaction of styrene groups with vinyl of siloxane, the obtained polystyrene siloxanes ( P1 - P3 ) showed high thermostability with the 5 % weight loss temperature ( T 5d ) of above 440 °C and the residue at 1000 °C of over 40 %. Thanks to the introduce of trifluoromethyl with large free volume, P3 exhibited low dielectric constant ( D k ) of 2.45 and ultralow dielectric loss ( D f ) of 3.41 × 10 −3 at high frequency of 10 GHz. Meanwhile, P1 - P3 remained stable dielectric properties after being soaked in boiling water for 72 h. In particularly, all polymers exhibited good transparency with transmittance of 90% varying from 500 nm to 1000 nm. These materials can meet the requirements of matrix materials or packaging resins used in high-frequency communication equipment.