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An introduction to silicone

At Silicone Engineering, we are frequently asked many questions regarding silicone and its applications. To give you a basic understanding, we’ve compiled the top five most commonly asked questions to give you all the knowledge you need.

What is silicone?

As they say in those famous shampoo adverts: ‘here is the science bit’. Silicones are polymers, which are large molecules composed of many repeated sub-units. These polymers are made up of siloxane – a chain of alternating silicon atoms and oxygen atoms frequently combined with carbon and/or hydrogen. Silicon is an element found in sand, where it is extracted from and passed through hydrocarbons.

Why is silicone more expensive than other rubbers?

Being made from sand means that silicon is the second most abundant element on Earth, yet despite being readily available the cost is relatively high in comparison to other rubbers such as natural rubbers, Neoprene and EPDM. The reason for this is that the process of converting sand into silicon is expensive. Furthermore, while it is popular, silicone is not used as widely as some other materials so the economies of scale are low. For many businesses, though, the cost of silicone is easily justified as it’s the best in class elastomer for extreme temperature environments where other rubbers simply can’t function. We have examined the reasons for the high cost of silicone in more detail on our blog post ‘Why is silicone classed as premium rubber?’.

Why choose silicone rubber?

Silicone rubber is an elastomer and is non-reactive, stable and resistant to extreme environments and temperatures. Due to these characteristics, silicone is frequently used in Rail, cars, , aircraft , electronics and HVAC systems.

What temperatures can silicone withstand?

What makes silicone so popular for use in so many products and applications is the wide variety of temperatures it can withstand whilst maintaining its properties and physical structure. Silicone is ideal for use in continuous temperatures as low as -60°C to as high as around 230°C. However, the amount of time spent in extreme temperatures beyond these values is important. Silicone cannot withstand the highest or lowest temperatures for too long. We have written more about this in our blog post ‘What temperatures can silicone rubber withstand?’.

What is the shelf life of a silicone product?

The shelf life of your silicone product will be affected by several different factors. For example, placing your silicone product in perfect temperature controlled conditions would give it a long shelf life, generally up to 10 years. However, exposing it to extreme temperatures will degrade the material over time and therefore reducing the shelf life. We have explored this issue in more detail in our blog post: ‘What is the shelf life of a silicone product?

How can you tell the difference between Silicone and EPDM?

EPDM is frequently black, there are no noticeable visual differences between silicone and EPDM from an aesthetic view point, you can colour EPDM like silicone but you usually find the material being produced in a black or dark grey.

You can tell the difference between Silicone and EPDM by exposing a small piece to a naked flame, EPDM would burn with a black ash and black smoke whilst silicone would burn with a white ash and white smoke. The white ash and white smoke released by the silicone are actually silicon dioxide.

The white smoke is much lower in toxicity compared to other rubbers, the main item of combustion of silicone rubber is silicon dioxides.

Also, silicone rubbers tend to be easier to cut with a knife, and are easier to bend than an equivalent sized piece of EPDM.

What’s the difference between latex and silicone?

Latex is an organic rubber, the type that is extracted from the Pará rubber tree (Hevea brasiliensis), a member of the spurge family. In regards to latex’s physical properties the rubber is super stretchy, very high tensile strength and mechanical strength but on the flipside is very vulnerable to heat! Environmental exposure latex doesn’t hold up too well when exposed to the elements, UV light and general wreathing degrade the material rapidly under conditions that silicones can withstand for years.

When it comes to service temperature range there’s no comparison, silicones can happily survive at extremes of both high and low temperature that would destroy a sample of latex.

Where is silicone rubber used?

Silicone rubber is frequently used in the following sectors

  • Aerospace
  • Automotive
  • Communication Infrastructure (EMI)
  • Construction
  • Dairy
  • Displays
  • Electronics
  • Energy
  • Food & Beverage
  • Heat press and vacuum forming
  • HVAC
  • Industrial
  • Marine
  • Military
  • Oil and Gas
  • White Goods

What now?

So, now you will have a basic understanding of silicone. These five queries give you a small flavour of some of the frequently asked questions, but our team of experts will be happy to answer any other enquiries you might have and go into detail to help you find the silicone product best for you. You can contact us via the contact us page, or call us on 0845 674 4747.

Alternatively, view our products to find the right silicone solution for your business!

About the author

Simon Holmes
 

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