Rubbers are natural or synthetic elastomers characterized by elasticity, waterproofness, and electrical insulating properties used to obtain rubber and ebonite through vulcanization process.
The first patent for the process of producing butadiene synthetic rubber using sodium as a polymerization catalyst was issued in England in 1910. The first small-scale production of synthetic rubber by a technology similar to that described in the English patent took place in Germany during the First World War.
The commercial production of synthetic rubber began in 1919 in the US (Thiokol), and by 1940 more than 10 of its brands were produced in the world. The main producers were the USA, Germany and the USSR.
In Germany, butadiene-sodium rubber found a rather wide application under the name “Buna”.
Synthesis of rubbers has become much cheaper with the invention of Ziegler-Natta catalysts.
Isoprene rubbers – synthetic rubbers obtained by polymerization of isoprene in the presence of catalysts – metallic lithium, peroxide compounds. Unlike other synthetic rubbers, isoprene rubbers, like natural rubber, have high tackiness and are slightly inferior to it in elasticity.
At present, most of the produced rubbers are butadiene-styrene or butadiene-styrene-acrylonitrile copolymers.
Rubbers with heteroatoms as substituents or having them in their composition are often characterized by high resistance to the action of solvents, fuels and oils, resistant to the action of sunlight, but have the worst mechanical properties. The most common in the production and use of rubbers with hetero substituents are chloroprene rubbers (neoprene) – polymers of 2-chlorobutadiene.
On a limited scale, thiokols are produced and used: polysulfide rubbers obtained by polycondensation of dihaloalkanes (1,2-dichloroethane, 1,2-dichloropropane) and alkali metal polysulphides.