Silicone LSR (Liquid Silicone Rubber)

Ethylene propylene diene monomer rubber — THE outdoor/weather elastomer. Saturated backbone gives outstanding ozone, UV, and weathering resistance. Excellent resistance to steam, hot water, and polar solvents. NOT resistant to oils/fuels (opposite of NBR). Good electrical insulation. ρ 0.85-1.3 (lightest common rubber). Used for automotive door/window seals, roofing membranes, radiator hoses, HVAC gaskets, and pond liners.

Carbon fiber reinforced epoxy — the benchmark structural composite material. Unidirectional ply: tensile strength 1500–2000 MPa, modulus 120–150 GPa at density 1.55 g/cm³ (5x stronger than steel at 1/5 the weight). Quasi-isotropic layup: UTS ~600 MPa, E ~50 GPa. Autoclave-cured prepreg (aerospace) or infusion/RTM (industrial). Used in aerospace primary structures (fuselage, wings), Formula 1 chassis, bicycle frames, wind turbine blades, pressure vessels (Type IV) and high-end sporting goods. Fiber types: T300, T700, T800, M40J, M55J.

Fluoroelastomer — THE high-temperature and chemical-resistant rubber. Outstanding resistance to oils, fuels, acids, and solvents at temperatures up to 200°C (short-term 230°C). Fluorine content (64-70%) determines chemical resistance. Trade names: Viton (Chemours), Tecnoflon (Solvay), Dai-El (Daikin). 5-10x more expensive than NBR. Used for aerospace fuel seals, chemical process seals, automotive fuel injector O-rings, semiconductor processing, and any seal exposed to aggressive chemicals at high temperature.