6.3.4 Silicone
Silicones are unique materials that combine the advantages of glass (silicone-based) and plastic (carbon-based). Like glass, silicones are temperature and moisture resistant, chemically inert and have good dielectric properties. Similar to plastics, silicones can assume many shapes and forms and remain strong and flexible while exhibiting excellent thermal stability.
Broadly speaking, 1C silicone elastomers have outstanding properties and are far superior to conventional organic elastomers. They exhibit excellent mechanical strength in harsh environments and can be used at temperatures ranging from -50°C to +350°C (-58°F to +660°F). They typically possess hardness in the range of 30-80 Shore A, excellent tear strength (15-40 N/mm2) and elongation at break varying from 150% to 800%. The ageing resistance of silicones highlights their core qualities: they are chemically inert, photo-oxidatively stable and free from residual reactive groups once cured.
Silicones are classified based on the curing method as follows:
- 1C condensation cure RTV
- 2C condensation cure RTV silicones
- 2C addition cure RTV silicones
- 1C heat cure silicone rubbers
- UV-curing silicone rubbers