Phenyl Silicone Rubber: Breaking the Low-Temperature Limit

Standard methyl vinyl silicone rubber typically has a brittleness temperature around -50°C to -60°C. Phenyl Silicone Rubber (PVMQ), by introducing phenyl functional groups onto the siloxane backbone, significantly reduces the crystallization temperature of the molecular chain, achieving a brittleness temperature as low as -120°C — making it one of the best low-temperature-resistant elastomer materials known. Beyond extreme low-temperature performance, the introduction of phenyl groups also imparts the following unique advantages:

• Radiation Resistance: The benzene ring structure effectively absorbs and disperses high-energy radiation, suitable for nuclear industry environments
• Ablation Resistance: Forms a dense char layer under high-temperature flames, protecting internal materials
• High Refractive Index: Higher phenyl content yields a higher refractive index, ideal for optical encapsulation
• Excellent Damping Properties: Maintains good shock absorption and energy dissipation across a wide temperature range

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Phenyl Silicone Raw Gum: The Base Material for High-Performance Products

Phenyl Silicone Raw Gum is an un-compounded, high-molecular-weight linear polyphenylsiloxane, serving as the base polymer for manufacturing all solid phenyl silicone rubber products. Based on phenyl content, it is classified into three categories: Low-Phenyl Raw Gum (5%~10% phenyl content)

• Focuses on extreme low-temperature performance, with brittleness temperature down to -120°C
• Applications: Aerospace low-temperature seals, O-rings, and sealing for polar research equipment

Medium-Phenyl Raw Gum (10%~25% phenyl content)

• Balances low-temperature resistance and ablation resistance
• Applications: Rocket engine nozzles, high-temperature sealing gaskets

High-Phenyl Raw Gum (>25% phenyl content)

• Focuses on radiation and ablation resistance, with a refractive index exceeding 1.46
• Applications: Nuclear power plant cable insulation, LED optical encapsulation, rocket nozzles

Phenyl silicone raw gum typically has a molecular weight between 500,000 and 1,000,000, with Mooney viscosity adjustable based on downstream processing needs. The raw gum itself is not directly usable; it must be compounded with reinforcing fillers, structural control agents, and vulcanizing agents to produce final products.

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Phenyl Silicone Compound: Ready-to-Use Finished Rubber

Phenyl Silicone Compound is produced by mixing phenyl raw gum with reinforcing fillers (such as fumed silica), structural control agents (such as hydroxyl silicone oil), and peroxide vulcanizing agents using open mills or internal mixers. Users can directly mold, extrude, or inject the compound without self-formulating. Core Advantages of Phenyl Silicone Compound:

• Standardized Formulation: Consistent batch-to-batch performance, reducing variability from user self-compounding
• Easy Processing: Direct molding or extrusion after milling; typical vulcanization temperature is 170°C~180°C
• Diverse Specifications: Customizable by hardness (Shore A 30~80), color, and phenyl content

Typical Application Areas:

• Aerospace: Low-temperature seals, O-rings, gaskets
• Electronics: Radiation-resistant cable insulation, high-temperature wire jackets
• Optics: LED encapsulation lenses, optical seals
• Industrial: Ablation-resistant sealing gaskets, high-temperature rollers

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Phenyl Silicone Elastic Putty: High-Damping Shock Absorption Material

Phenyl Silicone Elastic Putty is a special low-crosslink-density phenyl silicone material with unique viscoelastic and high-damping properties,介于 between solid rubber and viscous liquid. Core Properties:

• Extreme Low-Temperature Elasticity: Remains elastic at -120°C without brittle cracking
• High Damping Energy Absorption: Deforms like a high-viscosity liquid under impact to absorb energy, with a damping coefficient far exceeding standard rubber
• Weather and Radiation Resistance: Excellent resistance to ozone, UV, and radiation
• Self-Extinguishing: Self-extinguishes when removed from flame, without additional flame retardants

Typical Application Scenarios:

• Elastic damping bodies in railway locomotive shock absorbers
• Fixation and buffering of precision aerospace instruments
• Damping shock-absorbing components in bridge bearings
• Impact protection layers for military equipment

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Phenyl Silicone Oil: Versatile Fluids from Lubrication to Optics

Phenyl Silicone Oil is a low-molecular-weight polyphenylsiloxane liquid. Based on phenyl content and viscosity, it is classified into the following categories: Low-Phenyl Silicone Oil (5%~10% phenyl content)

• Viscosity range: 10~1000 cSt
• Features: Excellent low-temperature fluidity, pour point below -80°C
• Applications: Extreme low-temperature lubricants, damping fluids, vacuum diffusion pump oils

Medium-Phenyl Silicone Oil (~25% phenyl content)

• Viscosity range: 50~5000 cSt
• Features: Balances low-temperature performance and thermal stability
• Applications: Base oil for high-temperature grease, mold release agents, cosmetic additives

High-Phenyl Silicone Oil (>45% phenyl content)

• Viscosity range: 100~10000 cSt
• Features: Refractive index up to 1.50+, excellent radiation resistance
• Applications: Refractive index modifier for LED encapsulants, optical lens immersion oil, nuclear industry damping fluids

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Comparison: Phenyl Silicone vs. Standard Silicone vs. Fluorosilicone

表格

Performance Dimension	Standard Silicone	Fluorosilicone	Phenyl Silicone
Low-Temp Resistance	-60°C	-60°C	-120°C
Fuel/Solvent Resistance	Poor	Excellent	Moderate
Radiation Resistance	Fair	Fair	Excellent
Ablation Resistance	Fair	Fair	Excellent
Damping Properties	Fair	Fair	Excellent
Refractive Index	1.40~1.41	1.38~1.39	1.42~1.55
Cost	Low	High	Medium-High

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Industrial Selection Guide

1. Extreme Low-Temp Sealing (<-60°C): Choose low-phenyl silicone rubber or phenyl compound
2. Oil Resistance + Low Temp: Choose fluorosilicone rubber
3. High Damping Shock Absorption: Choose phenyl elastic putty
4. Radiation Environment: Choose medium-to-high phenyl silicone rubber
5. Optical Encapsulation / High Refractive Index: Choose high-phenyl silicone oil or high-phenyl raw gum
6. Ablation/Fire Resistance: Choose medium-to-high phenyl silicone rubber

Phenyl silicone rubber IOTA BHTV 3830 series