Sustainability has been a major concern in meeting the world's growing demand for natural rubber, especially with the rise of pneumatic tires used on bicycles and vehicles starting in the 1890s. While natural rubber is a renewable resource, there were some areas where the material could not meet the needs of many of modern products. For example, natural rubber melts at around 350F, and it is also too brittle for applications that need to be flexible without losing structural integrity. Because of all of this, the world was finally introduced to synthetic rubbers in the early 1900s.
What Is Synthetic Rubber?
An elastomer is a material that has the mechanical property that allows it to undergo much more elastic deformation under stress than most materials. It can also still return to its previous size without permanent deformation.
Synthetic rubber, invented in 1909, is any man-made/artificial elastomer created by linking polymer molecules. Their polymers are made from petroleum byproducts. It isn't until certain chemicals are added to the native form of rubber that it becomes the rubber material that you're more accustomed to seeing in everyday products.
History of Synthetic Rubber
The history of synthetic rubber actually dates back to 1826, when Michael Faraday showed that natural rubber consisted of a hydrocarbon with five carbon atoms and eight hydrogen atoms. Then, in 1860, G. Williams pyrolyzed (decomposed through heating to a high temperature) raw natural rubber by dry distillation. The distillate was called isoprene, a building block of most synthetic rubber materials today.
It wasn't until 1909 that Florentijn Hofman was able to first patent synthetic rubber after using isoprene obtained from mineral sources.
Synthetic rubber coming off the rolling mill at B.F. Goodrich back in 1941. Image Source: Library of Congress
How is Synthetic Rubber Made?
Step 1: The process begins with the refining of coal, oil, or other hydrocarbons
Step 2: Naphtha (a flammable liquid hydrocarbon mixture) is combined with natural gases to produce monomers—such as styrene and isoprene—which bind molecules together to create polymers
Step 3: Next, the monomers that were produced will generally be subjected to either an emulsion or solution polymerization process to turn the individual polymers into polymer chains, which form a rubber substance
Step 4: Finally, the rubber substance will be processed into a rubber product using techniques such as vulcanization. This technique converts polymers into more durable material by adding accelerators, such as sulfur.
Types of Synthetic Rubber
When it comes to synthetic rubbers, there are a variety of chemicals that are used to make synthetic rubbers. On top of that, countless additives can be added to the materials to modify their properties, such as carbon black being added to silicone to make it conductive. The most common synthetic rubber types include:
- Acrylic Rubber (ACM)
- Butadiene Rubber (BR)
- Butyl Rubber (IIR)
- Ethylene Propylene Diene Monomer (EPDM)
- Fluoroelastomers (FKM) / Viton
- Isoprene Rubber (IR)
- Nitrile Rubber (NBR)
- Perfluoroelastomer (FFKM)
- Polychloroprene (CR) / Neoprene
- Polysulfide Rubber (PSR)
- Silicone Rubber (SiR)
- Styrene Butadiene Rubber (SBR)
Synthetic Rubber Fun Facts
- Roughly 33 billion pounds of rubber is produced yearly, 2/3rds of which is synthetic.
- Production of synthetic rubber expanded exponentially during World War II since Germany & Japan controlled the majority of the world's supplies of natural rubber by mid-1942
- Chewing gums were initially made with natural rubber until after World War 2, when synthetic rubbers were developed as an alternative.
Synthetic Rubber Applications
Companies use synthetic rubber in a number of ways. Below are just a few to give a general idea of where you'll find this form of rubber.
Automotive Applications: Tires, grommets, panel plugs, seals & gaskets, drive belts, and much more.
Masking Applications: Silicone and EPDM are commonly used for higher temperature processes, like powder coating & electrocoating.
Sealing Applications: Outside of automotive, synthetic rubber is commonly used for sealing strips due to its favorable weather properties.
Synthetic rubbers were developed to address various concerns, including oversupply issues, global sustainability, and higher performance needs. You'll come across more synthetic rubbers in your daily life compared to natural ones. Whether it's your children's toys, rubber pads, or even chemically resistant gaskets in your vehicle, synthetic rubbers play a significant role in our lives. While synthetic rubber has many advantages over natural rubber, one of the unfortunate downsides of it is that it is not biodegradable because it consists of inorganic materials.
That said, we live in a world constantly searching for more advanced materials and technologies. So, the question is, what will be next? Will we develop a new material that outperforms both natural & synthetic rubber? Or will we find ways of advancing existing materials, like silicone and EPDM? Well, that's all we have for this post. We hope you enjoyed it! Be sure to subscribe below as we continue this series, and check out our post on Natural Rubber below in case you missed it!