Rubber has come a long way since its introduction in Europe by Christopher Columbus. In 1496, Christopher Columbus returned from his voyage to the West Indies and brought with him the first rubber balls. Prior to rubber balls, Europe had only known leather balls and was instantly awed by the bounciness of rubber. When we look at the timeline of rubber from its initial introduction to the present, rubber has significantly evolved in its manufacturing, production and uses. Today, we don’t just use natural rubber, but synthetic rubbers as well. Synthetic rubbers (or elastomers) or thermoplastic products are derived from petroleum by-products amongst other materials. Two of the most commonly used types of synthetic rubber are Santoprene rubber and Styrene-Butadiene rubber (SBR). Artificial elastomers gained popularity during World War II when natural rubber became scarce. Substituting the natural elastomer, many different kinds of thermoplastic products were produced.
Synthetic rubbers are artificial polymers with the capability to undergo elastic deformation under tension but can retain its previous stature without any permanent deformity. Almost all types of synthetic rubber exhibit formidable stretch-ability and durability features. Manufacturers also prefer thermoplastic products because of their processing ease that allows them to be reproduced and remanufactured conveniently, as well as, cost-effectiveness attributed by their sustainability benefits and reduction in system costs.
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Types of Synthetic Rubber: Santoprene and Styrene-Butadiene
Santoprene is a family of synthetic rubbers produced from natural elastomer and polypropylene (plastic). It is a type of thermoplastic elastomer that is a result of cross-linking EPDM rubber and polypropylene together, thus creating a material that has excellent flexibility and durability properties. The production of Santoprene rubber is similar to the way plastic is produced, evident by the word “plastic” in its name, which also alludes to its straightforward manufacturing process. In conjunction with its elastomeric capabilities, the thermoplastic material can survive in extreme temperatures without cracking or deforming. Santoprene rubber is known for withstanding continuous temperatures up to 275 degrees Fahrenheit and intermittent temperatures up to 375 degrees Fahrenheit. This is an additional reason why manufacturers prefer Santoprene rubber to other elastomers.
The chemical compatibility of Santoprene has proven resistant against many chemicals, including methanol, natural gas and oils. Much like neoprene, Santoprene also possesses superior defense against fluids, UV rays, weathering and the ozone. Santoprene material does not easily age or become damaged. It is one of the thermoplastic products that are commonly used in automotive, building and construction, electrical, household, and healthcare applications because it can maintain effectiveness under immense tension, extreme temperatures, and interior and exterior aggravations.
Other commonly used synthetic rubbers are Styrene-Butadiene rubber (SBR) products. Styrene Butadiene rubber is one of the most versatile copolymer rubber compound. SBR material consists of styrene, which is a colorless liquid that instantaneously evaporates when it comes into contact with air, and butadiene, which is a reactive colorless gas. Essentially, SBR is comprised of styrene organic compound and triple the amount of chemical butadiene. The styrene and butadiene ratio is important because it determines the polymer’s properties. For example, the higher level of styrene equals a less rubbery compound.
Styrene-Butadiene material is one of the most abrasion resistant synthetic rubbers. When protected by additives, SBR also has good aging stability. Similar to Santoprene rubber, SBR exhibits heat resistance as well. Yet unlike Santoprene material, Styrene-Butadiene is a general-purpose elastomer that has low elasticity and poorer low temperature performance.
I.G. Farbenindustrie developed SBR in Germany during the 1930s. At this time, it was first called an emulsion styrene-butadiene rubber (E-SBR) because of its emulsion procedure that utilized polymerization. The polymerization process enabled Germans to produce a material that had low reaction viscosity but retained all the properties of natural rubber. These types of synthetic rubber aided the country because Germans did not have to resort to depleting their natural rubber resources. Instead, they were able to stretch out and develop on their elastomeric resources. Eventually, other countries began producing SBR, including the United States. By 1955, the production of SBR in the United States became completely privatized. Today, Styrene-Butadiene rubber is used in automobile tires, children’s toys, shoe soles, chewing gum and much more.
Synthetic rubbers and thermoplastic products are very valuable resources for many industries. For instance, in the automotive industry, Santoprene rubber and SBR can be used under the hood of the car, as gasket seals, or automobile tires. Both types of synthetic rubber have some level of abrasion, chemical, fluid, heat, ozone and weathering resistance. Depending on your application, either type of elastomers will most likely get the job done. Both of the artificial elastomers are cost effective and enable manufacturers to reduce system costs, such as decreased usage of adhesives, chemicals and heat processing. Also, instead of solely relying on natural rubber, most artificial elastomers are recyclable.
The value of synthetic rubbers is clearly demonstrated through the evolution of how it is produced and manufactured. Throughout the decades, Santoprene and SBR have revolutionized the way artificial elastomers are used. From household appliances to sanitation purposes, these compounds are commonly used for various purposes in numerous industries.