Surface modification of phenyl silicone primarily involves the introduction of specific functional groups or radicals to adjust its surface properties, significantly improving the material's performance in extreme environments. The following is a comprehensive analysis of key modification methods and their impact on performance:

I. Surface Modification Methods
Chemical Modification
Phenyl Introduction: Through the copolymerization of a methylphenyl tricyclic ring (A3) with a vinyl ring (VMC), phenyl groups are introduced into the polysiloxane side chain, disrupting molecular chain regularity, lowering the crystallization temperature, and enhancing thermal stability.
Coupling Agent Treatment: Using a silane coupling agent or a compound modifier, the material binds to the surface of the silica powder through a hydrolysis reaction, improving compatibility and dispersibility.

Physical Blending
Blending with fluorosilicone or nitrile silicone utilizes the polarity of the fluorine or nitrile groups to enhance oil and solvent resistance while maintaining low-temperature elasticity.

II. Effects of Modification on Performance
Heat Resistance
When the phenyl content is 5-10%, the glass transition temperature can be lowered to below -100°C, maintaining low-temperature elasticity. When the phenyl content is 20-40%, flame resistance is significantly improved, and self-extinguishing properties are achieved.
High-temperature stability is enhanced, as the side chain phenyl groups inhibit oxidative decomposition, allowing long-term use at temperatures up to 250°C.

Mechanical and Chemical Properties
After modification with a coupling agent, the activation index of silica powder increases to 82.4%, and the oil absorption value decreases to 0.264 mL/g, enhancing interfacial bonding with the polymer matrix.
Fluorosilicone modification improves chemical resistance and is suitable for components in contact with fuel oil.

Functional Extensions
Amino-modified silicone oils can be combined with phenyl silicone oils to enhance the softness of textile finishes.
Radiation resistance increases with increasing phenyl content. High-phenyl silicone oils (40-50%) can withstand 1×10⁸ roentgen gamma rays.

III. Expanded Applications
Aerospace: Ablation-resistant seals, low-temperature elastic components.
Electronic and electrical appliances: High-insulation packaging materials, high-temperature potentiometer seals.
Industrial deep refrigeration: Sealing materials below -100°C.
Through precise control of phenyl content and modification processes, phenyl silicone can meet diverse requirements from extreme low temperatures to high-temperature radiation environments.