To discuss silicones is really to talk about a material enhancer and enabler rather than a specific material. Based on the crucial ingredient of silicon, which is one of the most abundant elements on earth, silicones add value to a whole range of applications that take advantage of its properties, which include temperature resistance and a warm, soft, rubbery tactile feel. One innovative product that makes full use of silicone’s qualities is Sugru: this mouldable, self-setting product can be used to adapt existing products in a number of ways, as shown by the modification of a tool handle, opposite, to give it a non-slip, comfortable grip.
The extreme versatility of silicones means they can be formulated to deliver improved functionality in everything from inks and paints to fabrics, coatings and, of course, silicone rubber. Silicones can also be partnered with other materials for enhanced performance. In 1943, scientists at Corning Glass and Dow Chemical started producing silicone rubber made from carbon, hydrogen, oxygen and silicon. The material has a long list of impressive properties: it is incredibly flexible and tactile, and its appearance can vary from watery translucent tones to completely opaque colours; its working temperature range is phenomenal, extending all the way from -100°C (212ºF) up to +250°C (482ºF). Silicone is also chemically inert; which, coupled with its flexibility, makes it suitable for a range of medical applications, including prostheses and orthopaedic cushions.
Image: Sugra silicone rubber
Key features
•Difficult to mould
•Excellent chemical resistance
•Excellent heat resistance
•Excellent flexibility
•Readily accepts colour
•Comparatively expensive
•Shock absorbing
•Not recyclable
Cost
£5–12 ($8-19) per kg. depending on grade.
Sustainability issues
Not recyclable or biodegradable, but is absorbed by solids in waste water treatment facilities.
Production
Silicones can be injection moulded, extruded, calendared, blow moulded, rotational moulded and printed as inks.
Typical applications
The list of applications for silicones is vast depending on its form. It can be used as sealant in packaging as well as for bathroom sealant; it can be used as the basis for inks printed onto textiles that won’t crack when stretched, and can be used for high temperature applications such as cooking dishes.
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–Extremely versatile –Excellent resistance to heat and chemicals –Wide range of production techniques –Widely available |
–Comparatively expensive –Can be difficult to mould –Not recyclable |