Polybutadiene is a synthetic rubber which has high wear resistance. Its elasticity ensures a post-stress recovery of 80%. Chemically, polybutadiene is a polymer consisting of monomeric units of cis-1,4-butadiene. The polymerization mechanism depends on the reaction conditions, specially on the catalysts used. The formation of bridges due to the presence of double bonds, contributes to the elasticity of the polymer. Polybutadiene undergoes vulcanization to further improve its chemical, physical and mechanical quality, in relation to the intended use.
Depending on the percentages of specific isomeric subunits present, the following categories of polybutadiene can be obtained:

• High-cis polybutadiene: consisting of a large quantity of cis units (> 93%) and just a few vinyl units (<4%), it is synthesized using Ziegler-Natta catalysts and its properties vary depending on the metal used. They can have from low to high mechanical strength.
• Low-cis polybutadiene: Obtained by using an alkyl-lithium as a catalyst (e.g. N-butyl lithium), it typically contains 40% cis, 50% trans and 10% vinyl units. It is used as an additive for other plastics.
• High-vinyl polybutadiene: Synthesized using an alkyllithium catalyst, it contains more than 70% vinyl units. It is used to produce quality tires. A particular type, with 90% vinyl content and a syndiotactic configuration, is sold by a Japanese company and represents a thermoplastic elastomer (at room temperature).
• High-trans polybutadiene: Obtained with catalysts similar to those used for the high-cis variety, it is a crystalline plastic (not elastic) that melts at 80°C. It is used in the production of golf balls.
• Metallocene polybutadiene: Newly synthesized by Japanese researchers, a metallocene is used as a catalyst, enabling various percentages of cis/trans/vinyl units in the composition.