What Is Phenyl Silicone Raw Gum?
Phenyl silicone raw gum, also known as phenyl silicone rubber raw gum, phenyl MQ raw gum or phenyl-vinyl silicone rubber raw gum, is a high-molecular-weight polysiloxane elastomer containing phenyl functional groups in the main chain.Compared with ordinary methyl vinyl silicone rubber raw gum, phenyl silicone raw gum introduces phenyl structures into the polymer chain, significantly improving radiation resistance, low-temperature flexibility, heat aging resistance and elastic retention.
Phenyl silicone raw gum itself is a high-viscosity elastomer, usually supplied as blocks, rubber lumps or translucent rubbery material. It cannot be used directly as a finished product, but serves as the base raw material for phenyl silicone rubber, phenyl compounded rubber, radiation-resistant silicone rubber, low-temperature silicone rubber and specialty sealing elastomers.After compounding with reinforcing fillers, structural control agents, vulcanizing agents and additives, it can be processed into phenyl silicone compounded rubber, and then molded, extruded or injection-molded into seals, gaskets, tubes, wire and cable jackets and high-temperature elastomer parts.
The product should be stored sealed, protected from light and moisture, and kept away from acidic or alkaline substances, heavy-metal impurities and peroxide vulcanizing agents.
Key Technical Indicators
Phenyl Content
Phenyl content is the most important indicator of phenyl silicone raw gum, directly affecting low-temperature resistance, radiation resistance, heat resistance and elasticity. Common phenyl content ranges from about 3% to 15%, with some high-phenyl grades available.At lower phenyl levels, the material behaves closer to ordinary silicone rubber; as phenyl content increases, low-temperature performance and radiation resistance usually improve significantly, but hardness and processability also change, requiring balanced selection.
Vinyl Content
Phenyl silicone raw gum usually contains a certain amount of vinyl groups for peroxide vulcanization or addition-cure systems. Vinyl content affects crosslink density, tensile strength, compression set and curing speed.Different grades may have vinyl contents around 0.05%-0.3% or higher, depending on the downstream vulcanization system and performance requirements.
Volatility
Volatility reflects the level of low-molecular-weight substances in the raw gum. Excessive volatility may cause bubbles, dimensional instability or surface defects during compounding, molding or extrusion.High-quality phenyl silicone raw gum typically has low volatility, commonly no more than 1%-2% after heating at 150°C for 2 hours, subject to product specifications.
Mooney Viscosity and Molecular Weight
Phenyl silicone raw gum is usually characterized by Mooney viscosity. If Mooney viscosity is too low, green strength may be insufficient; if too high, compounding and extrusion become more difficult. Different grades vary widely, and selection should match compounding equipment, filler systems and molding processes.
Service Temperature Range
Phenyl silicone rubber made from phenyl silicone raw gum can typically maintain elasticity from about -60°C to +200°C, with some grades able to withstand higher temperatures for short periods.Compared with ordinary silicone rubber, phenyl silicone rubber is less likely to harden or become brittle at low temperatures and shows better performance retention under radiation exposure.
Radiation Resistance
Phenyl groups can absorb part of the radiation energy and reduce scission of the siloxane main chain, giving phenyl silicone rubber better radiation resistance than ordinary silicone rubber. This makes it suitable for aerospace, nuclear-related sealing, wire and cable and electronic-electrical protection applications.
Storage Stability
Phenyl silicone raw gum should be stored sealed, away from high temperature, direct sunlight and contamination. Long-term exposure to air or contact with impurities may cause surface skinning, viscosity changes or vulcanization performance variation. Typical shelf life is 6-12 months, subject to the supplier's technical data.
Main Performance Features
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Excellent low-temperature flexibility: phenyl groups improve elastic retention at low temperatures.
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Strong radiation resistance: suitable for radiation environments and high-reliability sealing materials.
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Good heat aging resistance: maintains elasticity after prolonged high-temperature exposure.
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Base polymer for phenyl compounded rubber: compatible with silica, structural control agents and vulcanizing agents.
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Adjustable phenyl/vinyl ratio: can be tailored for low-temperature, radiation-resistant, hardness and curing requirements.
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Suitable for multiple molding processes: supports compression molding, extrusion and injection molding.
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Non-hazardous transport: many grades can be shipped as non-dangerous goods, supporting international sampling and bulk delivery.
Typical Application Scenarios
Base Polymer for Phenyl Compounded Rubber
Phenyl silicone raw gum is the main base polymer for phenyl compounded rubber. It can be compounded with fumed silica, hydroxyl silicone oil, structural control agents, heat-resistant additives and peroxide vulcanizing agents to produce phenyl silicone rubber with different hardness levels, colors and performance profiles.
Low-Temperature Silicone Rubber Products
Used for low-temperature seals, gaskets, tubes and cold-resistant elastomer parts, reducing the risk of hardening, cracking or loss of elasticity in ordinary silicone rubber at low temperatures.
Radiation-Resistant Silicone Rubber Materials
Suitable for aerospace, nuclear-related equipment, radiation-environment seals and radiation-resistant wire and cable jackets, improving performance retention under irradiation.
Aerospace Sealing Elastomers
Applied in aircraft and spacecraft seals, gaskets, O-rings and elastomer jackets, meeting wide-temperature and long-term reliability requirements.
Wire and Cable Jacket Materials
In specialty wires and cables, phenyl silicone rubber can be used for high-temperature, low-temperature, radiation-resistant and flame-retardant modified jacket systems, improving electrical insulation and environmental resistance.
High-Temperature Elastomers and Specialty Seals
Used in engine-area seals, industrial high-temperature gaskets, sensor seals, electronic-electrical protection parts and high-temperature molded products, balancing heat aging stability and elastic recovery.
Selection and Usage Recommendations
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Select phenyl content by low-temperature requirements: higher phenyl content generally improves low-temperature performance, but hardness and processability should be evaluated together.
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Confirm vinyl content for the curing system: peroxide vulcanization and addition-cure systems have different vinyl requirements.
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Control volatility and impurities: low volatility helps reduce bubbles, surface defects and dimensional variation.
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Match with reinforcing filler systems: optimal performance requires suitable silica, structural control agents and heat-resistant additives.
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Store separately from vulcanizing agents: keep away from peroxide vulcanizing agents, platinum catalysts and acidic/alkaline substances.
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Key points for overseas customers: highlight customizable phenyl content, low-temperature resistance, radiation resistance, heat aging stability, phenyl compounded rubber base polymer function and stable supply, supporting sampling, compounding trials and bulk orders.
Methyl phenyl vinyl silicone rubber IOTA 3120
