Silicone rubber has a variety of excellent properties, but its mechanical properties such as compressive strength and tearing strength are poor, and cannot meet the requirements of the process. Fillers need to be added to modify and strengthen it. When MQ silicone resin is used as a reinforcing filler, it can not only increase the strength of the rubber matrix, but also will not increase the viscosity of the system too fast to facilitate subsequent operations, and the prepared vulcanizate has better transparency.

The organic part of MQ silicone resin can improve its compatibility with silicone rubber and play a role in tackifying; the energy-saving silicon-oxygen chain can improve the mechanical strength, cohesive strength, peeling strength and high temperature resistance of silicone rubber, and play a reinforcing role. Addition vulcanized silicone rubber is mainly composed of vinyl-containing raw rubber, reinforcing filler, hydrogen-containing silicone oil crosslinking agent and platinum catalyst. Under the action of the platinum catalyst, the vinyl-containing MQ resin can chemically bond with the raw rubber through the hydrosilylation reaction with the SiH crosslinking agent, thereby forming a three-dimensional network structure for reinforcement. With the increase in the amount of MQ silicone resin, the hardness, tensile strength, tear strength, adhesive properties, and crosslinking density of silicone rubber gradually increase to the optimum value. The reason is that the molecular weight of MQ silicone resin is relatively small, the vinyl content is relatively high, the compatibility and dispersibility in silicone rubber are better, and it is chemically combined with silicone rubber. However, when the cross-linking density is too large, the distribution of cross-linking points is not uniform, resulting in stress concentration, and the silicone rubber becomes hard and brittle, and the silicone rubber is easily broken under the action of stress. The curing time is prolonged with the increase of the amount of MQ. This is due to the small molecule of MQ and the high vinyl content, which can preferentially react with hydrogen-based silicone oil, thereby delaying the reaction of silicone hydrogen and vinyl raw rubber until the MQ is consumed. As the amount of MQ resin increases, the dielectric constant of silicone rubber increases to its maximum value and approaches equilibrium. However, if the amount of MQ resin is too large, the cross-linking of the silicone rubber is excessive, which limits the activity of the polar groups and stabilizes the dielectric constant. However, the dielectric properties of silicone resin are still lower than ordinary rubber.

Condensed vulcanized silicone rubber is mainly composed of silicone rubber containing terminal hydroxyl or alkoxy groups, reinforcing fillers, crosslinking agents and catalysts. After the catalyst or the moisture in the air, the cross-linking agent is hydrolyzed to generate silanol, which undergoes condensation reaction with the silanol of the raw rubber to form a three-dimensional network structure, which is vulcanized to an elastomer. When MQ silicone resin is mixed with silicone rubber, it can increase the viscosity and strengthen the silicone rubber, so that the silicone rubber has excellent mechanical properties. However, when exposed to electromagnetic radiation and vacuum ultraviolet radiation, the silicone rubber will age, deform, and crack, and its performance will change accordingly. Difference. The main reasons for the decrease in quality and performance of silicone rubber caused by irradiation are the escape of unreacted low-molecular substances in the vulcanized rubber under irradiation, the breaking of the macromolecular network structure, and the degradation or cross-linking of molecular chains. In order to make the silicone rubber resistant to radiation, you can add anti-radiation fillers, such as nano-TiO2.