In 1935, German chemists synthesized the first of a series of synthetic rubbers known as "Buna rubbers". These were "copolymers", meaning the polymers were made up from not one but two monomers, in alternating sequence. One such Buna rubber, known as "GRS" (Government Rubber Styrene), is a copolymer of butadiene and styrene, became the basis for U.S. synthetic rubber production during World War II.
Worldwide natural rubber supplies were limited and by mid-1942 most of the rubber-producing regions were under Japanese control. Military trucks needed rubber for tires, and rubber was used in almost every other war machine. The U.S. government launched a major (and largely secret) effort to develop and refine synthetic rubber. A principal scientist involved with the effort was Edward Robbins.
By 1944 a total of 50 factories were manufacturing it, pouring out a volume of the material twice that of the world's natural rubber production before the beginning of the war.
After the war, natural rubber plantations no longer had a stranglehold on rubber supplies, particularly after chemists learned to synthesize isoprene. GRS remains the primary synthetic rubber for the manufacture of tires.
Synthetic rubber would also play an important part in the space race and nuclear arms race. Solid rockets used during World War II used nitrocellulose explosives for propellants, but it was impractical and dangerous to make such rockets very big.
During the war, California Institute of Technology (Caltech) researchers came up with a new solid fuel, based on asphalt fuel mixed with an oxidizer, such as potassium or ammonium perchlorate, plus aluminium powder, which burns very hot. This new solid fuel burned more slowly and evenly than nitrocellulose explosives, and was much less dangerous to store and use, though it tended to flow slowly out of the rocket in storage, and the rockets using it had to be stockpiled nose down.
After the war, the Caltech researchers began to investigate the use of synthetic rubbers instead of asphalt as the fuel in the mixture. By the mid-1950s, large missiles were being built using solid fuels based on synthetic rubber, mixed with ammonium perchlorate and high proportions of aluminium powder. Such solid fuels could be cast into large, uniform blocks that had no cracks or other defects that would cause non-uniform burning. Ultimately, all large military rockets and missiles would use synthetic rubber based solid fuels, and they would also play a significant part in the civilian space effort.
|ISO Standard Code||Chemical Name||Common Names|
|CIIR||Chloro Isobutylene Isoprene||Chlorobutyl, Butyl|
|ECO||Epichlorohydrin||ECO, Epichlorohydrin, Epichlore, Epichloridrine|
|EPDM||Ethylene Propylene Diene||EPDM, Nordel|
|EVA||Ethylene Vinyl Acetate||EVA|
|FKM||Fluoronated Hydrocarbon||Viton, Kalrez, Fluorel|
|HNBR||Hydrogenated Nitrile Butadiene||HNBR|
|IR||Polyisoprene||(Synthetic) Natural Rubber|
|IIR||Isoprene Butylene Butyl||Butyl|
|NBR||Butadiene Acrylonitrile||NBR, Nitrile, Perbunan, Buna-N|
|SBR||Styrene Butadiene||SBR, Buna-S, GRS|