Effects of Synthetic Process on the Properties of Silicone Resin Composed of Polysiloxane Block Copolymer

Abstract

One component room temperature vulcanized (RTV) silicone resin was prepared by combination of a kind of polydimethylsiloxane-b-phenylsilsesquioxane copolymer with crosslinker and catalyst. The effects of feeding order on properties of cured silicone resin were studied in detail. When hydroxyl terminated polydimethylsiloxane was added in three times and the D/T ratio was 2.0~2.3 during synthesis, the cured resin with the hardness over 20Shore D had the better elastic-plastic properties and heat resistance than the other two feeding orders. The tensile strength was over 3MPa and the elongation at break was above 75%. The Td5% was 416.6°C.The silicone resin also had good radiation resistance. At the radiation dose of 1500kGy, there was no obvious defect observed in the material, and the tensile strength increased to 6.83MPa, while elongation at break decreased to 26%.