As a key active component of addition-cured phenyl silicone rubber, Phenyl Vinyl Silicone Oil IOTA-252 (Di-vinyl-terminated Phenyl Methylsiloxane, CAS: 225927-21-9) offers well-defined structure, controllable reactivity, and batch-to-batch consistency, and has been reliably used for years in high-temperature, radiation-resistant, and high-insulation silicone rubber applications.

IOTA-252 is a colorless, transparent, oil-like liquid. Its main chain contains phenyl and methylsiloxane units, with vinyl groups terminating both ends, allowing participation in platinum-catalyzed addition reactions. The product is available in a range of viscosities (100–5000 mm²/s) with vinyl contents from approximately 0.4% to 3.1%, enabling users to select according to desired crosslinking density. It has a refractive index of 1.50–1.54, a density of 1.05–1.10, and a flash point above 100°C, combining good processing safety with thermal stability.

Thanks to the introduction of phenyl groups, silicone rubbers or resins prepared from IOTA-252 exhibit excellent wide-temperature performance (–60°C to over 300°C), radiation resistance, low compression set, and high electrical insulation. They are widely used in aerospace seals, LED encapsulants, nuclear power equipment elastomers, and as reactive diluents for high-performance phenyl silicone resins. Compared to ordinary methyl vinyl silicone oils, IOTA-252 shows slower aging under extreme conditions, with better light transmittance and dimensional stability.

Feedback from multiple silicone rubber manufacturers indicates that this product contains few impurities, has minimal vinyl content variation, and shows excellent compatibility with hydrogen-containing crosslinkers. The curing process is smooth, producing finished products with fewer bubbles and higher transparency, making it especially suitable for optical-grade or high-reliability applications.

IOTA-252 is packaged in 15 kg or 200 kg internally coated steel drums and shipped as a non-hazardous material. It is recommended to store the product sealed in a cool, dry place, avoiding contact with moisture or residual catalysts. Under unopened conditions, the shelf life is typically 6–12 months.

With the continuous growth of demand for specialty silicone materials in aerospace, electronics, and new energy industries, IOTA-252, as a mature and reliable domestic functional silicone oil, provides strong support for the localized supply of high-end silicone products.