In this guide, you will find all the information about silicone material such as properties, manufacturing process, applications, classification criteria, and many more.
It will help you become an expert in the silicone industry.
What Is Silicone Material?
Silicone is an inert material made from inorganic units of [–SiO2–], which form its basic structure.
You can also refer to the material as polysiloxane.
Simply put – it is a synthetic material with rubber and plastic properties.
The compound is available as oil/liquid, rubber, or resin.
What Is Silicone Made Of
Silicone is a synthetic compound consisting of different elements such as:
Of course, this forms the main chain of silicone material. However, the side chain may have other organic units.
The organic units give different silicone properties. As a result, you can make hybrid materials for many applications.
At the same time, you should not confuse silicon with silicone.
Silicon is a product of silica (silicon dioxide). Silica comes from quartz or sand.
Silicone Manufacturing Process
Producing silicone material involves a series of chemical reactions such as reduction, hydrolysis, and polymerization.
Generally, these processes may vary depending on the final silicon product, such as:
- Silicone resin
- Silicon fluid
- Silicone rubbers, etc.
Silicone manufacturing process involves the following key stages:
Step 1: Heat a mixture of gravel or quartz and carbon source at about 1800˚C.
This will produce silicon and carbon monoxide. Here, the main interest is silicon, which is critical in step 2.
Step 2: Next, mix silicon with methyl chloride and heat.
It will cause a chain reaction producing dimethyldichlorosilane. Dimethyldichlorosilane is the backbone of silicone material.
Step 3: You will distill dimethyldichlorosilane, separating chlorosilanes compounds.
Then, you should add water to produce disilanol and hydrochloric acid
Step 4: Disilanol will condense, forming polydimethylsiloxane with hydrochloric acid as a catalyst.
As you can see, polydimethylsiloxane has a siloxane bond.
Through the polymerization process, you can get different grades of silicone, such as resin, liquid, or rubber.
Comparing Siloxane Bonds And Molecular Structure
We enjoy the desirable properties of silicone material due to its unique molecular structure and bond.
For the scope of this guide, you will only learn the basic concept of bonds and the structure of silicone material.
You will find more resources at the end of this guide in case you wish to learn more.
Siloxane Bonds And Molecular Structure
The main chain of siloxane is [-Si-O-Si-]. It forms the backbone of this material. However, it may have additional side chain groups.
As a result, silicone material will have both organic and inorganic properties.
Furthermore, the strong bond explains silicone’s ability to withstand high temperatures or heat. Even at 200°C, the siloxane high energy bonds will not break.
Of course, the high energy bonds also explain high resistance to chemicals and weatherability.
Again, six Si-O bonds, existing in 360° helical design, guarantee a high degree of flexibility.
For instance, silicone materials may exist as:
- Silicone fluids –are known for their moderate molecular weight
- Silicone elastomers – these groups are known for high molecular weight with cross-linked polymers
- Silicone resins – Although they have low molecular weight, there are functional hydroxyl or alkoxy groups.
Interestingly, they can undergo hydrolysis forming highly cross-linked structures.
Of course, you can achieve these when manufacturing silicone.
Although silicone may have ethyl (CH3) and vinyl (CH2), the absence of carbon in the backbone structure makes it a unique polymer.
Silicone Material Proprties
Many properties make silicone suitable for numerous applications. Some of these properties include:
- High thermal stability – it can withstand temperatures between -100 °C and 250 °C depending on the additives.
- Low toxicity level – this is due to its chemical stability. So far, silicone has been approved for use in healthcare and food processing industries.
- Low chemical reactivity – silicone is inert. Therefore, it does not react with most chemicals hence suitable for healthcare and food processing.
- Low thermal conductivity and better insulation properties – silicone has the best electrical and thermal insulation. However, by adding certain additives such as graphite, silicone material can become conductive.
- Excellent water repellant – this makes silicone perfect for manufacturing water tight sealing systems.
- High resistance to UV light, ozone, and oxygen – silicone is not affected by these gases. Therefore, making material perfect for most outdoor and indoor applications.
- High gas permeability – it is nearly 40 times better than the natural rubber material
- Non-flammable material – silicone is not combustible. Incorporating certain additives can make silicone self-extinguishing.
- Does not support microbial growth – this silicone property makes material perfect for most hygienic applications.
Applications Of Silicone Material
Silicone is available in solid or liquid form. As a result, you can use silicone in many applications, such as:
- Personal care products – main applications include shampoos, cosmetics, conditioners, skin care products, etc.
- Construction industry – helps prevent bacterial and moisture build-up in construction materials.
- Painting and coating – you mix paint with silicone to enhance performance and durability.
- Solar panels – help improve the efficiency of solar panels
- Electrical and electronics – you can make a range of products such as rollers, keypads, parts of mobile electronics, LED lighting, etc.
- Aerospace industry – adhesives and sealants play an integral role.
They seal engine gaskets, hydraulic systems, electrical devices, doors, windows, etc.
- Kitchenware – Most cookware use silicon seals. Others include chocolate molds, non-stick cookware, lids, etc.
- Lubricants and sealants – there are many silicone sealants and greases in the market.
- Apparel – goggles and diving masks are made from silicone
- Toys – due to the material’s low toxicity, they are the perfect choice for most toys. Silicon baby toys are popular.
- Cleaning – silicone forms part of the dry cleaning solvent
- Medicine industry – Some of the main applications of silicone include scar treatment sheets, implants, ophthalmology, etc.
In short, silicone is a perfect choice for most applications.
Types Of Silicone Material
Although there are many silicone compounds available in the market, here are the four main options:
i. Room temperature vulcanizing (RVT) – They are a perfect choice for sealing and bonding since they set or cure at room temperature.
ii. Liquid silicone rubber (LSR) – You need a platinum catalyst to cure these silicones at high temperatures.
iii. Fluorosilicone Rubber (FSR) – They are known for excellent resistance to fuels and oils. FSR is a popular sealant in the aerospace industry.
iv. High consistency rubber (HCR) – This silicone has high molecular weight. It is common in medical devices.
Apart from these, silicone may take many forms, such as emulsion, oil, resin, caulk, liquid, solid, grease, gel, or foam.
As you can see, silicone is a versatile material that plays a critical role in most industries. It is mainly due to extraordinary properties similar to rubber and plastic.
However, before choosing silicone material, ensure the formulations meet your application’s requirements.
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