Synthesis and characterization of liquid silicone rubber for LED packaging

Methylphenylcyclosiloxane was synthesized by hydrolysis with methylphenyldimethoxysilane and sulfuric acid. The vinyl silicone oil was synthesized by tetramethyl ammonium hydroxide as a catalyst with methylphenylcyclosiloxane, methylvinylcyclosiloxane, Octamethylcyclotetrasiloxane and tetramethyldivinyldisiloxane, in 110°C. Silicone rubber has been cured with vinyl silicone oil and hydrogen silicone oil at a certain temperature, chloroplatinic acid as catalyst. And the effect of the concentration of vinyl, the distribution of vinyl, molecular size and the distribution of phenyl on the properties of silicone rubber was studied. The results show that The concentration and the distribution of vinyl groups are two important factors which affect the strength of silicone rubber. As the concentration of phenyl groups in vinyl silicone oil increase, the transmittance of silicone rubber decrease and the heat resistance of silicone rubber increase.