The Influence of Vinylsilane on Various Properties of Silicone Rubber

The raw materials for vinyl silane coupling agent

The R&D department of organic silicon studied the sulfurization characteristics of methyl vinyl silicone rubber, the mechanical properties of sulfurized rubber, and the effect of silicone rubber and aluminum alloy shear adhesive strength of vinyl silane coupling agent SiSiB PC6130 and PC6120.

The main raw materials are methyl vinyl silicone rubber; 4# gas-phase white carbon black; hydroxyl silicone oil; crosslinking agent, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, referred to as DBPMH; organic silicon coupling agents SiSiB PC6130 and PC6120.

The influence of vinyl silane on silicone rubber

Under the same formula and process conditions, organic silicon blended 4phr of silicone rubber stock, of which 3phr were added with 2phr of silane coupling agents SiSiB PC6130 and PC6120, and the remaining 1phr was left blank for comparison without adding anything. Then, the sulfurization characteristics were measured with a vulcanization instrument.

The torque value of the vulcanization kinetic curve of the rubber material added with the coupling agent was significantly reduced compared with the torque value of the blank comparison rubber material without adding the vinyl silane coupling agent, and the vulcanization rate slowed down.

SiSiB PC6130 has a small impact on the sulfurization rate and torque of silicone rubber, so R&D personnel use SiSiB PC6130 as a variable experiment. When different amounts of organic silicon product SiSiB PC6130 were added to several rubber stocks, it was found that as the amount of coupling agent increased, the sulfurization rate of silicone rubber slowed down, and the larger torque value also decreased.

Compared with the blank comparison rubber material, the vulcanization mechanical properties of the rubber material added with SiSiB PC6130 increased by 20% in tensile stress, tensile strength, and tear strength, and the elongation at break and hardness also increased. Therefore, the appropriate amount of A-172 in silicone rubber is 2-4 phr.

The influence of different varieties of silane coupling agents on the mechanical properties of silicone rubber is different. SiSiB PC6130 has a greater contribution to the tensile strength of silicone rubber than SiSiB PC6120, but the effect on the elongation at break of silicone rubber is opposite.

Within the range of 2-4phr of silane coupling agent, the shear adhesive strength of silane coupling agent increases with the increase of the amount of the agent, and reaches a maximum value when the amount is 4phr. When the amount exceeds 4phr, the shear adhesive strength shows a decreasing trend; the contribution of SiSiB PC6120 to the shear adhesive strength of silicone rubber is better than that of SiSiB PC6130.

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