Phenyl silicone rubber exhibits excellent weather resistance, superior ozone aging resistance, and stable sealing properties in the field of ozone-resistant sealing materials, making it particularly suitable for long-term sealing applications in high-ozone environments.
I. Ozone Resistance Characteristics of Phenyl Silicone Rubber
Molecular Structure Advantages
The main chain of phenyl silicone rubber contains phenylsiloxane or methylphenylsiloxane linkages. The large volume phenyl groups introduced into its molecular structure disrupt the regularity of the siloxane structure, lowering the crystallization temperature and glass transition temperature of the polymer, allowing the material to maintain excellent elasticity even under extreme temperature conditions. This structural feature makes its molecular chains less susceptible to damage in ozone environments, enabling the material to maintain stable performance over the long term.
Ozone Aging Resistance Mechanism
Unlike ordinary rubber, the ozone resistance of phenyl silicone rubber mainly stems from its highly saturated molecular structure. Ozone primarily attacks the unsaturated double bonds in the rubber molecular chains, while the main chain of phenyl silicone rubber is composed of saturated hydrocarbons, with only a small number of unsaturated double bonds in the side chains. This significantly reduces the susceptibility to ozone attack.
Wide Temperature Range Stability
Phenyl silicone rubber can continuously maintain its elasticity in the range of -100℃ to +70℃, and some high-phenyl content products even have a temperature resistance range of -100℃ to 250℃. This wide temperature range stability allows it to effectively resist ozone aging under different climatic conditions. II. Influence of Phenyl Content on Ozone Resistance
Low Phenyl Silicone Rubber (5-10 mol% phenyl content)
Optimal low-temperature performance: Hardening temperature is reduced to the lowest value (-115℃), and it still maintains flexibility and elasticity at -100℃.
Application areas: Particularly suitable for sealing applications requiring low-temperature and ozone resistance in extremely cold regions, such as building seals in polar research stations and vehicle sealing systems in high-altitude areas.
Medium Phenyl Silicone Rubber (15-25 mol% phenyl content)
Ablation resistance and self-extinguishing properties: As the phenyl content increases, the rigidity of the molecular chain increases, and the flame resistance characteristics gradually become apparent, significantly improving self-extinguishing performance.
Application areas: Suitable for applications requiring simultaneous ozone resistance, high-temperature resistance, and flame retardancy, such as aircraft engine compartment seals and nuclear power plant containment seals.
High Phenyl Silicone Rubber (30-50 mol% phenyl content)
Excellent radiation resistance: Can withstand 2.58 × 10⁴ C/kg gamma ray radiation while maintaining good ozone resistance.
Application areas: Particularly suitable for ozone-resistant sealing in high-radiation environments, such as nuclear reactor sealing systems and spacecraft sealing components.

III. Specific Applications in Ozone-Resistant Sealing Materials
Aerospace Field
Spacecraft sealing systems: IOTA 3108 RTV phenyl silicone rubber remains elastic at temperatures as low as -120°C and also possesses excellent radiation resistance, ablation resistance, and self-extinguishing properties. It is used in spacecraft thermal insulation materials and hatch sealing systems.
Engine thermal insulation components: High-phenyl silicone rubber is used in engine thermal insulation components to effectively resist aging in high-altitude ozone environments.

Automotive Industry Applications
Door seals: Phenyl silicone rubber seals are used in automotive manufacturing to test ozone cracking resistance, simulating material hardening or cracking problems caused by long-term outdoor exposure.
Engine sealing systems: Used in automotive engine seals, maintaining good sealing performance in high-temperature and ozone environments to prevent oil and gas leakage.
Construction Field Applications
Building sealants: Phenyl silicone rubber is used in building sealants to effectively resist outdoor ozone, UV radiation, and moisture erosion, ensuring long-term sealing performance.
Waterproofing membranes: Used in ozone aging resistance testing of roofing waterproofing membranes to evaluate their resistance in ozone environments, preventing discoloration, powdering, or leakage due to aging.
Energy and Nuclear Power Fields
Nuclear power radiation-resistant coatings: IOTA 3108 phenyl silicone rubber is used as a radiation-resistant coating for nuclear power plants, possessing both ozone and radiation resistance.
Nuclear reactor sealing systems: High-phenyl silicone rubber is used in nuclear reactor sealing systems, capable of resisting long-term aging in high-radiation and ozone environments.
Electronics and Electrical Appliances Fields
Electronic component sealing: Used as a sealing material for electronic components, protecting them from ozone and moisture erosion and ensuring electrical insulation performance.
Cable sheath materials: Used as a sheath material for wires and cables, possessing excellent ozone aging resistance, preventing insulation performance degradation or brittle failure.