In order to explore the best reaction conditions for the preparation of methoxy functionalized MQ silicone resin (MMQ), methyl vinyl containing MQ silicone resin (mvmq) and trimethoxysiloxane (TMOS) were used as the main raw materials under the catalysis of chloroplatinic acid (H2PtCl6), MMQ was prepared by hydrosilylation. The mass fraction of unreacted vinyl in mvmq was determined by Iodimetry, and the conversion of vinyl was determined. The effects of reaction temperature, reaction time, catalyst dosage and molar ratio Si-H / si-ch = CH2 on the conversion of vinyl were investigated. Fourier transform infrared spectrum was used, FT-IR and 1H-NMR were used to characterize the structure of the adduct. The results showed that MMQ was successfully prepared. The optimum reaction conditions were: reaction time 6 h, reaction temperature 80 ℃, catalyst dosage 10 μ g / g (based on mvmq mass) and molar ratio Si-H / si-ch = ch21.3:1. The conversion of vinyl reached 78.58%.
The transparent liquid silicone rubber was prepared with vinyl silicone oil and hydrosilicone oil as basic polymer, hexamethyldisilazane as modifier, fumed silica as reinforcing filler, hydroxysilicone oil as structural control agent and vinyl MQ silicone resin(VMQ
) as auxiliary reinforcing agent. The effects of the amount of hexamethyldisilazane, fumed silica, hydroxysilicone oil and vinyl MQ silicone resin on the light transmittance of silicone rubber were studied. The results show that the transmittance of silicone rubber increases gradually with the increase of the amount of fumed silica reaching 30 phr, the transmittance of silicone rubber increases gradually with the increase of the amount of hexamethyldisilazane and vinyl MQ silicone resin, and the transmittance of silicone rubber increases gradually with the increase of the amount of hydroxysilicone oil, but when the amount of hydroxysilicone oil exceeds 5 phr, Its light transmittance began to decline. The best formula is 100 phr vinyl silicone oil, 6 phr hexamethyldisilazane, 40 phr fumed silica, 5 phr hydroxy silicone oil, 15 phr vinyl MQ silicone resin. The light transmittance of silicone rubber is 90.5%.