- Materials & Industrial Technology
What is Silicone? How is Silicone Made?
What is SIlicone?
Silicone is used in everything from medical equipment to electronic devices, but very few people outside the engineering world know what the material is. Sure, silicone comes from sand (among other ingredients) but the process to refine and produce a grade of silicone that can be used in industrial applications is complex and interesting. This article will describe the chemical properties of silicone from a consumer’s point of view, and it will describe the process by which silicone is produced. We will focus primarily on the type of silicone that is made for flexible silicone keypads and other electronic applications, as it is the most common form of the material.
Silicone vs. Silicon
To begin with, there is an important distinction between silicone (the material that is commonly used in industrial applications and for water-proofing) and the chemical element silicon. Silicon, like carbon, is an element that is found in tons of materials throughout the world. More of the Earth’s crust is comprised of silicon than carbon!
Silicone is a polymer that is made up of silicon and a number of other elements, including hydrogen, carbon, and oxygen. Much of the challenge of silicone production is refining pure chemical silicon as a base ingredient.
Benefits of Silicone
Silicone is a fantastically useful material in industrial, scientific, and consumer applications. Silicone is functionally inert – so it doesn’t react with other materials and it won’t degrade over time as a result of oxidation or exposure to the elements.
Silicone doesn’t conduct heat well, and it won’t conduct electricity – which makes it perfect for coatings on materials that are designed to get extremely hot (or cold) or wires that carry currents. Silicone is commonly used in electronic equipment because it can separate electrically active elements, and it can be used as an insulator to prevent static electricity from damaging components.
Silicone contains no organic material, so fungus and bacteria find silicone far too hostile of an environment for long term growth. This makes silicone perfect for use in hospitals and in laboratories where ease-of-disinfection is important. Silicone also repels water, and it can be used for waterproofing or for creating a single surface that can be easily wiped off with anti-bacterial cleaner.
Silicones are actually inorganic-organic polymers, on a sliding scale because they combine the inorganic silicon-oxygen chain as well as organic side groups. There are many different types of silicones based on their chemical composition – so it is a reliant and flexible material that can be used for oils, resins, liquids, gels, and solids. Most people are familiar with the various states of silicone. As a liquid, silicone is often used as a lubricant (like WD-40) and as a solid it can be utilized for hard-plastics or for flexible silicone keypads and keyboard protectors.
How is Silicone Produced?
Before silicone can be manufactured, it must first go through a number of chemical steps to refine it from its most common form. Most of our silicone comes from silica which is the main ingredient in sandstone and beach sand. Silica, or silicon dioxide, is not chemically pure enough to use for silicone production – so first the silicon has to be separated out.
Usually, chemical companies will produce silicone with caulks silyl acetates, although some laboratories use the faster (but more wasteful) silyl chloride method. The type of polymer chain that will be produced can be altered with different precursors, allowing the chemical companies to determine the type of material that is created. If you have pure silicone, you can ‘reverse’ this chemical process by burning it in oxygen, causing a white powder of silicon dioxide to form.
Many Uses of Silicone
Because of its versatility, and the fact that it can be made to be completely water/chemical resistant, silicone is used in many industries. Virtually every complex product that you use on a daily basis takes advantage of silicone in some way.
- Automobiles use silicone to seal the windows from weather, and there is also silicone in brake components to lubricate the parts since it won’t wear down as fast as other lubricants and it doesn’t collect dust like petroleum products would.
- Silicone caulking is used throughout homes and businesses to protect surfaces that are regularly exposed to water. Silicone is the main ingredient in many household lubricants as well, and it can be found in some residential wiring and in electrical boxes as an insulator.
- Silicone is used by many industrial companies to produce keypads that go in remote controls, computers, and other electronic devices. Silicone keypads are flexible, cheap, and they can be made to a variety of specifications and used for all types of purposes.
Silicone is inert, and it doesn’t produce waste that would be considered toxic to the environment. Silicone is suitable for medical applications and controlled atmosphere buildings because there is no off-gassing of compounds.
On the other hand, silicone does not bio-degrade – so products containing silicone should not be disposed of in land-fills. Additionally, silicone takes a large amount of energy to produce, even if the catalysts are re-usable, so it is not necessarily a sustainable material.