Abstract:Diphenyl silicone rubber raw rubber and methylphenyl silicone rubber raw rubber with different benzene silicon ratio (Ph/Si) were designed and synthesized to explore the relationship between raw rubber structure and application performance.The DSC analysis results of the raw rubber show that in the phenyl modified silicone rubber raw rubber, the molar number of phenyl silicone oxygen links is the main factor affecting the low-temperature crystallization and melting of silicone rubber.Diphenyl silicone rubber raw rubber with the same benzene silicon ratio of 5% is crystalline rubber, while methylphenyl silicone rubber raw rubber is amorphous rubber. The analysis results of physical and mechanical properties of silicone rubber vulcanizates show that the tensile strength and elongation at break of phenyl silicone rubber are significantly improved after hot air aging test,and the structure of phenyl siloxane links has no significant effect on heat resistance.The low temperature DMTA analysis results of the vulcanizates show that the glass transition temperature of the phenyl silicone rubber vulcanizates is related to the ratio of benzene to silicon, but the structure of the phenyl siloxane links has little effect on glass transition temperature. With the increase of the ratio of benzene to silicon, the glass transition temperature moves to the high temperature direction.The analysis results of compression cold resistance coefficient show that under the same benzene silicon ratio of 5%, the amorphous methyl phenyl silicone rubber has better low-temperature performance, and the crystalline diphenyl silicone rubber loses rubber elasticity under long-time compression due to low-temperature crystallization.