Full definition
Vinyl-methyl-siloxane rubber — an inorganic elastomer based on a silicon-oxygen backbone (Si-O-Si) rather than the carbon backbone of organic rubbers, providing the widest useful temperature range of any commercial elastomer: -60 to +230°C continuous (special grades to +300°C). Key properties: excellent biocompatibility (FDA 21 CFR 177.2600, USP Class VI), non-toxic and odorless, outstanding ozone and UV resistance (essentially permanent outdoor exposure), excellent electrical insulation, and high-temperature compression set resistance. ASTM D2000 classification: FC/FE/GE depending on grade. Limitations: low tensile strength (5-10 MPa, weakest of common elastomers), poor abrasion resistance, poor resistance to hydrocarbon solvents and steam, and relatively high cost ($8-25/kg). Applications: food-grade seals and gaskets (bakery oven conveyors, beverage dispensers), medical devices (tubing, implants), automotive spark plug boots, LED encapsulation, high-temperature oven gaskets, baby products, and electrical insulation. Grades: standard VMQ, fluorosilicone FVMQ (fuel resistance + temperature), and liquid silicone (LSR, for injection molding). Manufacturers: Wacker (Elastosil), Dow (Silastic), Shin-Etsu, Momentive.