For these applications, an estimated 400,000 tonnes of silicones were produced in 1991. tooth impression molds), textiles and paper (e.g. keyboard pads), medicine and dentistry (e.g. gaskets), airplane (e.g., seals), office machines (e.g. insulation), electronics (e.g., coatings), household (e.g., sealants and cooking utensils), automobile (e.g.

Ullmann's Encyclopedia of Industrial Chemistry lists the following major categories of application: Electrical (e.g. This extends the uses of silicone sheeting to industries that demand hygiene, for example, food and beverage, and pharmaceuticals. Silicone can be developed into rubber sheeting, where it has other properties, such as being FDA compliant. Conversely, silicone rubbers cannot be used where gas-tight seals are necessary such as seals for high-pressure gasses or high vacuum.

High gas permeability: at room temperature (25 ☌), the permeability of silicone rubber for such gases as oxygen is approximately 400 times that of butyl rubber, making silicone useful for medical applications in which increased aeration is desired.

Because silicone can be formulated to be electrically insulative or conductive, it is suitable for a wide range of electrical applications. coatings, fire protection, glazing seals) and the automotive industry (external gaskets, external trim). This property has led to the widespread use of silicones in the construction industry (e.g.

Resistance to oxygen, ozone, and ultraviolet (UV) light.

Does not support microbiological growth.

Does not stick to many substrates, but adheres very well to others, e.g.

The ability to repel water and form watertight seals.

Thermal stability (constancy of properties over a wide temperature range of −100 to 250 ☌).

Silicones exhibit many useful characteristics, including: Properties This silicone rubber folding chessboard resists creasing and wrinkling. Polysiloxanes terminated with functional ligands such as vinyl, mercapto or acrylate groups have been cross linked to yield preceramic polymers, which can be photopolymerised for the additive manufacturing of polymer derived ceramics by stereolithography techniques. The pyrolysis of certain polysiloxanes under an inert atmosphere is a valuable pathway towards the production of amorphous silicon oxycarbide ceramics, also known as polymer derived ceramics. The readily dispersed powder is sometimes called silica fume. When silicone is burned in air or oxygen, it forms solid silica ( silicon dioxide, SiO 2) as a white powder, char, and various gases. Similarly, precursors with three methyl groups can be used to limit molecular weight, since each such molecule has only one reactive site and so forms the end of a siloxane chain.

This process can be used to produce hard silicone resins. Ideally, each molecule of such a compound becomes a branch point. SiH 2 Cl 2 + H 2 O ⟶ H 2 SiO + 2 HCl īranches or crosslinks in the polymer chain can be introduced by using organosilicone precursors with fewer alkyl groups, such as methyl trichlorosilane and methyltrimethoxysilane.

Silicone ring sizer printable