Is Silicone a Polymer, Elastomer or Rubber?

  1. S. Kipping, an English chemist from Manchester, invented the name “silicone” in 1901 for a chemical that combined atoms of silicon with carbon, hydrogen and oxygen in repeating molecular chains (a polymer). Polysiloxane is a more correct name, but today numerous closely related chemicals are commonly known as silicone and have an astonishing range of characteristics and applications. “Silicone” products come in many forms, including oils, grease, resins, caulk sealants and adhesives, but most people are familiar with it as a rubber-like material. In fact, many people confuse it with rubber.

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Rubber

Unlike synthetic silicones, rubber is a natural product derived from the latex of certain trees and plants. It is also a polymer, composed of repeating links of isoprene, but contains no silicon at all. In many products, sulphur, carbon and sand are sometimes added to harden it. Despite their different chemistry and origin, silicone and rubber have many similar qualities. This has led to their being used to make similar products.

Elastomers

The word “elastomer” is short for “elastic polymer”. Both rubber and silicone can be described as elastomers, since both are polymers that in most formulations have elastic properties. Even among engineers and chemists, the three words are sometimes used carelessly. Technically, to qualify as an elastomer a polymer must have both elasticity and viscosity, tolerate high strain before failure and have a low Young’s modulus (deform easily).

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Products

Although natural rubber has advantages over silicone in some products, the range of products made possible by silicone is much wider, including everything from liquid lubricants to hoses, tyres and gaskets. To get an idea of the range of colours, sizes and other characteristics of silicone products, or for expert advice on the best elastomer product to serve your purpose, ask a silicone hose manufacturer about silicone hoses.

The benefits of silicone over other elastomers include its high temperature toleration (it’s even used as a fireproof coating) and low toxicity, which makes good-quality silicone safe as cookware. At the other extreme, it retains its elastic resilience down to temperatures as low as -60 degrees Centigrade.

Its other useful qualities include environmental and chemical durability, ability to adhere to (and therefore seal) glass, electrical resistivity, non-toxicity to humans and animals and yet resistance to moulds, bacteria and fungi and (in contrast to rubber) low odour.

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