You should have heard these rubbery material terms before, but it may be a little difficult to explain exactly what these words are. Silicone can be called these words in different contexts, so do these equal silicone? It’s no wonder you can’t tell the difference; it can be very confusing indeed. In this article, we’re going to give you an overview of what the terms rubber, synthetic, polymer, and elastomer mean, to help you understand them better when choosing a specific material.
What Is a Polymer?
Definition of a Polymer
Polymers are macromolecules or polymeric materials that are formed by the accumulation of repetitive structural units that are linked together. These repeating units are formed along long chains in a certain order and have specific physical and chemical properties. They have physical properties of flexibility or rigidity.
Polymers are not always synthetic; natural polymers include natural rubber, cellulose, and proteins. Common synthetic polymers are polyethylene and polystyrene. One thing to emphasize here is that silicone is also a synthetic polymer.
Silicone as a Polymer
The chemical name of silica gel is Polysiloxane, and its constituent elements can be seen from the name; Poly stands for multiple repeating units. The molecular skeleton of silica gel is composed of repeating Si-O units. Isn’t it interesting? This silicone-oxygen bond is a chain-like structure with a high molecular weight. It has great flexibility over a wide temperature range. It is chemically stable.
What Is an Elastomer?
Definition of an Elastomer
Silicone is a polymer in terms of chemical materials. And Elastomer belongs to one of the categories of polymers. As mentioned earlier, polymers have two types of physical properties, and as you can tell from your experience, silicone is in the tough category. This is the elastomer. Elastomers are highly elastic polymers that can deform when subjected to an external force and return to their original shape when the force is gone. So, elastomers are actually polymers; they just belong to a subcategory of polymers.
Why Silicone Is Considered an Elastomer
Silicone is an elastomer that belongs to the group of polymeric materials. However, you should note that, as mentioned earlier, elastic polymers are elastomers. As we know, silicone is not just an elastic material. It can also be a liquid, a gel, or a highly viscous fluid. Silicone at this time is just a polymer with a chain-like molecular structure. At this time, there is no elasticity or fluidity.
Only when the silica gel undergoes cross-linking or vulcanization reaction does it belong to the elastomer; at this time, it is the molecular structure change from chain-like to a stable three-dimensional lattice structure. There are three types of cross-linking, namely RTV, HCR, and LSR. What we need is a chemical structure of the cross-linked silica gel that is stable, the properties are also very stable, and in different environments can maintain a stable state and performance. It has very good temperature resistance, oxidation, and UV resistance.
Every day, we see silicone products such as O-rings, gaskets, medical hoses, buttons, baby products, and so on that belong to silicone elastomers.
Why Silicone Is Commonly Called “Rubber”
Rubber is also a long-chain molecular structure and is a polymer. But not all polymers are rubber. Rubber is just a subset. Examples are plastics, polycarbonate, and nylon. There is no high elasticity in this class of materials. You may think that silicone and rubber are so much alike in physical properties; does silicone also belong to rubber?
What “Rubber” Means in Industry
In the industrial industry, any material that is highly elastic, has formed a cross-linked structure, and is able to return to its shape after being subjected to a force queen is rubber. You should be familiar with the description of elastomers. In this field, the focus is on the use of performance classification, rather than from the perspective of chemical materials. For example, natural rubber, nitrile rubber, fluoroelastomer, and so on are all rubber, but their chemical materials are not the same. From the point of view of this industry field, silicone meets the characteristics of rubber classification and can also be made into rubber.
Silicone Rubber ≠ Natural Rubber
Do you think that natural rubber and silicone rubber are rubbers with different raw material formulations? In fact, the two have completely different chemical properties and belong to two material systems.
Although silicone and rubber have some of the same characteristics, their chemical structure is not the same; the main chain of traditional rubber is carbon, while the main chain of silicone belongs to the silicone-oxygen structure. In terms of chemical structure, the bond energy of silicone is higher than that of rubber, and it exhibits better performance than traditional rubber, such as better resistance to high temperatures, better resistance to UV rays and aging, and the ability to maintain elasticity at extreme temperatures. Silicone is considered to be an upgraded version of rubber in terms of performance.
Why “Silicone Rubber” Is Widely Used
You may wonder why silicone and rubber are called silicone rubber when they have different chemical properties. In fact, this reason is very pragmatic; these two materials perform similarly in industrial applications, in order to facilitate communication and directly express the needs. For example, the material represents properties such as flexibility, sealing, and vibration damping. It’s a language that quickly establishes performance keywords. In practical applications, we focus on the performance of different materials, rather than distinguishing between what chemical elements the material is actually composed of. For example, if you need silicone, you will not say you need a cross-linked polysiloxane elastomer, right?
Is Silicone a Polymer, Elastomer, or Rubber?
See this, if you ask you silicone is rubber, or elastomer, or polymer, you should be able to draw some conclusions from the above introduction, but it seems as if the written answer is still plausible. Why can’t you tell the exact answer after reading? Now for you to reveal.
Because this question is relatively broad and one-sided, it is difficult for you to simply answer yes or no from one aspect. We have three perspectives to help you answer. From the most basic chemical structure, silicone is a polymer. In terms of performance, cured silicone is an elastomer. In terms of industrial applications, silicone is a rubber. Answering from these perspectives, you will be able to sort out the properties of silicone positioning. If these perspectives are missing, it is still difficult to answer the correct answer.
Materials
│
├── Polymer（Classification by chemical structure）
│ │
│ ├── Plastics
│ │
│ └── Elastomers（By Mechanical Behavior）
│ │
│ ├── Traditional Rubber
│ │ ├── NR
│ │ ├── NBR
│ │ ├── EPDM
│ │
│ └── Silicone
│ │
│ ├── LSR
│ ├── HCR
│ └── Silicone Rubber（After curing）
FAQ
Is Silicone A Plastic or A Rubber?
No, although they are both polymer materials, the main components are different; silicone has a silicone-oxygen main chain structure, and plastic is carbon carbon main chain structure. Silicone has high molecular bonding energy and is more heat-resistant and stable. Plastic is weak in heat resistance. And plastic in the heat will release harmful substances, while the chemical properties of silica gel are stable, and the material itself is non-toxic and hypoallergenic.
Is Silicone Rubber Safer than Traditional Rubber?
Yes. Silicone rubber is used in many applications. It is hypo-toxic, hypoallergenic, chemically stable, heat-resistant, and is often used as a food-grade and medical-grade product. However, you should not feel that all silicone is safe; if it is industrial-grade silicone is not suitable for human contact. However, in some application scenarios, the focus of silicone is not safety, but the need to wear and balance the cost. For example, common seals, tires, and industrial parts.
Is Silicone More Durable than Rubber?
Silicone rubber is more durable than rubber, but it’s not an absolute answer. It has to do with the environment of use, pressure, chemical exposure, etc. Chemically, silicone rubber is more resistant to temperature, UV, and weathering, andhas slower aging than rubber. However, rubber is also better than silicone rubber in that it is more resistant to tearing and has better abrasion resistance. In some chemical environments, such as oils, rubber is more resistant than silicone rubber.
Final Thought
From a chemical standpoint, silicones are polymers. From a performance standpoint. Silicone cures to become an elastomer. From the point of view of industrial applications, it can be seen as rubber. The materials suitable for different applications are different, and the terms should not be used in a mixed way. Conventional rubber and plastics are completely irreplaceable for high-performance silicone materials.
If you are looking for a reliable supplier of silicone functionality, Legensilicone can recommend itself. Our silicone materials are used in different application scenarios, and we have sufficient production equipment and high capacity to produce diverse silicone products. We support OEM/ODM customization to meet your different individual needs. All of our silicone products can take advantage of silicone’s temperature resistance, elasticity, and safety. If you are interested, please feel free to contact us!
