Phenyl Silicone Sealing Applications and Performance Requirements
Phenyl silicone is a special silicone material with unique performance advantages in sealing applications. According to research, phenyl silicone exhibits the following key performance characteristics:

[Heat Resistance]: Phenyl silicone exhibits excellent resistance to high and low temperatures. Low-phenyl silicone maintains elasticity at temperatures between -70°C and -100°C, medium-phenyl silicone is self-extinguishing, and high-phenyl silicone has a gamma-ray radiation resistance of up to 1×10⁸ roentgen. It also exhibits outstanding heat resistance, capable of long-term operation at 180°C and transient high-temperature resistance exceeding 300°C.

[Mechanical Properties]: It exhibits low compression set, oxidation resistance, weather resistance, shock resistance, and moisture resistance, making it an ideal sealing material.

[Chemical Stability]: Phenyl silicone exhibits excellent chemical inertness and does not react with most chemicals, making it an excellent choice for sealing applications in harsh chemical environments.

Application Areas: Primarily used in the aerospace industry, cutting-edge technologies, and other sectors of the national economy, such as cold-resistant rubber for the aviation industry, as well as seals, gaskets, pipes, and rods for areas resistant to ablation, heat aging, and radiation.

The reinforcing effect of nanofillers in phenyl silicone rubber is primarily achieved through the following mechanisms:
Surface Effect and Interface Strengthening
Nanoparticles (such as SiO₂ and Al₂O₃) form strong interfacial bonds with the polymer matrix due to their large surface area.

Volume Effect and Defect Repair
The size advantage of nanoparticles (<100 nm) enables them to fill microscopic defects that are inaccessible to micron-sized fillers.

Repair micropores and cracks within the matrix
Uniformize the electric field distribution
Reduce the probability of partial discharge

Typical Nanofiller Modification Characteristics
SiO₂ Modification: Surface hydroxyl groups promote polar interactions, and the high surface area increases carrier trap density. Experimental results show that adding 5wt% SiO₂ can increase the breakdown field strength of XLPE by 18%.
Al₂O₃ modification: High thermal conductivity improves thermal stability (thermal conductivity increases by 30%), and grain boundary structure inhibits space charge accumulation.
Synergistic modification effect: A SiO₂/Al₂O₃ composite (3:1 ratio) exhibits a 25% increase in tensile strength, a 65% decrease in space charge density, and a 50% increase in thermal conductivity.

The research on nanofiller-reinforced phenyl silicone rubber primarily utilizes the following methods:
Material Synthesis Methods
Professor Li Zhibo's team at Qingdao University of Science and Technology used an organic cyclotriphosphazene base (CTPB) as a catalyst to prepare high-molecular-weight diphenyl silicone rubber (DPSR) with controllable phenyl content via anionic ring-opening polymerization. This method allows precise control of the phenyl content, thereby regulating the material's properties.