Silicone rubber reinforced withsilicone rubber has excellent oil resistance. Its performance improvement mechanism, influencing factors and application advantages can be summarized as follows:

1. Mechanism of silicone rubber to improve the oil resistance of silicone rubber

Increase in cross-linking density

The abundant hydroxyl groups on the surface of silicone rubber form hydrogen bonds with the silicone rubber molecular chains, which promotes the increase of cross-linking density during vulcanization and reduces the free volume between molecular chains, thereby effectively inhibiting the penetration of oil substances.

Enhanced barrier effect

Nano-scale silica particles are evenly dispersed in the silicone rubber matrix to form a dense structure, which hinders the migration path of oil molecules and significantly reduces the swelling rate of silicone rubber in oil medium.

Enhanced chemical stability

The high-purity silica structure of silicone rubber has excellent compatibility with the silicone rubber matrix, reduces the chemical degradation caused by oil substances, and maintains the stability of the mechanical properties of the material.

2. Key factors affecting oil resistance

Type and dosage of silica

Vapor-phase silica (specific surface area 150-400m²/g) has a significantly better reinforcing effect than precipitated silica due to its finer particle size and higher surface activity.

The dosage is usually controlled at 10-40phr (parts of silica per hundred parts of rubber). Excessive addition will lead to a decrease in processing performance.

Silicone matrix type

High temperature vulcanized silicone rubber (HTV) has a denser molecular chain structure and better oil resistance than room temperature vulcanized silicone rubber (RTV).

Blending modification technology

Oil resistance can be further optimized by blending with fluoro silicone rubber, nitrile rubber, etc. For example, the swelling rate of fluoro silicone rubber blends in ASTM 1# oil at 200℃×48h is less than 12%.

Surface treatment process

Surface modification of silica using silane coupling agent (such as KH-550) can enhance its interfacial bonding with silicone rubber and reduce the adsorption of oil substances.