| Silicone materials, which have excellent properties, have been widely used in the fields of electronic and electrical equipment. With the development of power LEDs technology, the performance of encapsulation materials will be improved, especially high refractive index materials. It is particularly notorious that silicone materials exhibt poor mechanical properties if they were not reinforcened by fillers.As the most widely used fillers, although fumed silica can greatly improve the mechanical properties of silicone materials, but it still can not reach the optic properties requied by power LEDs encapsulant due to the difference in refractive index between silica and the matrix. In addition, using fumed silica to reinforce silicone rubber will dramatically improve the viscosity which would make it difficult to construct. It is because of the very good compatibility between the MQ resin and the silicone rubber matrix that makes MQ resin be followed with interest and studied recently. However, it is difficult to match the liquid silicone rubber with high refractive index and make its application is in control. Therefore, it is quite interesting to investigate MQ silicon resin with high refractive index and transmittance. In this paper, MQ resins were synthesized through hydrolytic condensation of ethyl polysilicate and vinylphenylmethylchlorosilane, then they were used to reinforce liquid silicone rubber and has obtained the very good effect. The specific worksin this paper are listed as follows:1?Different m/q of methyl phenyl vinyl MQ silicone resins were synthesized though the hydrolytic condensation of tetraethylorthosilicate (TEOS) with a new M monomer as end capping agent. In the meantime the MQ silicone resins were characterized by the method of F-TIR,1H NMR, GPC and Organic element analysis. On the basis of the 1H-NMR spectra, the degree of condensation were calculated. The refractive indexes were determined by abbe refractometer, MQ resins have high refractive index in between with 1.50?1.53, which make them have a high value of practical application.2?In the chemical experiment, the operation and the instillment reagent order's priority, has the very important function to experiment's success. By studying the instillment reagent order's priority, choice of cosolvent,and post-treating temperature,the optimum processing was got by orthogonal test. These included:added Q monomer droplets to M solution; the most appropriate solvent was isopropyl alcohol; the best processing temperature is 90?; acid-alkali catalysis could significantly improve aggregation degree.3?The non-isothermal curing behavior of MQ silicone resins/ methylphenyl hydro-silicone fluid (UC233) with different catalyst concentration were comparative studied by DSC. It was also demonstrated that the concentration of catalyst made difference on the activation energy. Finally, the optimum technological condition was determined that:the catalyst concentration was 15 ppm;[3=O,Ti=43.5?, Tp=95.2?,Tf=161.4?.4?The products prepared were applied to silicon rubber as a reinforcing agent, while the reinforcing performance and effect of it were investigated. The results showed that the properties of silicone rubber reinforced with 25% MQ resin content was better, and different silicone rubber had different reinforcing effect. Tensile strength was 0.83MPa, Hardness (Type A) was 85, index of refraction was greater than 1.51, light transmittance was about 95%.5?The storage modulus and glass-transition temperature were researched by dynamic mechanical thermal analyses(DMTA) for two curable silicone rubbers with 10% and 25% content of MQ silicone resin, and crosslink density was calculated, researches showed that lower content of MQ silicone resin led to the lower cross-linking density.6?The thermal stabilization of reinforced silicone rubbers were tested by TGA, researches showed that higher content of MQ silicone resin led to the superior thermal stability. |
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