Rubber Government

Nitrile rubber is also known as nihile-butadiene rubber (NBR), government rubber nitrile (GRN), and Buna N. 

Styrene-butadiene rubber (SBR) is also known as government rubber styrene (GRS) and Buna S. 

In 1942 the Japanese overran Malaya and the then Dutch East Indies to cut off the main sources of natural rubber for the United States and the British Commonwealth. Because of this the US Government initiated a crash programme for the installation of plants for the manufacture of a rubber from butadiene and styrene. This product, then known as GR-S (Government Rubber-Styrene), provided at that time an inferior substitute for natural rubber but, with a renewed availability of natural rubber at the end of the war, the demand for GR-S slumped considerably. (Today the demand for SBR (as GR-S is now known) has increased with the great improvements in quality that have been made and SBR is today the principal synthetic rubber). 

The Government Rubber Reserve Company in the 1940s pioneered the development of styrene-butadiene copolymers, by far the largest volume of synthetic rubber used today. Now usually known as SBR, it has also been called Buna-S, Rzrtadiene with a sodium (Na) catalyst and copolymerized... 

World War II brought a renewed urgency for synthetic rubber. When the Japanese occupied the Malay Peninsula and adjacent islands, the primary source of natural rubber to the United States was cut off. Rubber companies and university scientists cooperated in developing a procedure for manufacturing a synthetic rubber called GR-S (Government Rubber—Styrene). By the late 1930s,... 

As discussed in Chapter 4, emulsion polymerization received a significant boost in the United States during the Second World War. When Japan overran countries that supplied natural rubber to the West, a crash program to manufacture synthetic rubber was initiated in the United States and Canada. The product was called Government Rubber-Styrene (GR-S), and was produced by the emulsion polymerization of butadiene and styrene. The fundamental recipe for GR-S is still used as a teaching tool for those learning the art and science of emulsion polymerization. 

Large-scale manufacture of butyl rubber started during World War II, in the scope of the U.S. Government rubber-procurement program, and the actual process is essentially similar to the historical one [9]. Bromi-nated butyl (BIIR) was introduced in the 1950s by Goodrich Chemical Co. [54-56] but substantial commercial development occurred only in 1971 when the Polysar Ltd continuous and economic manufacturing process based on elemental bromine came onstream [57]. Production of chlorinated butyl (CIIR) was introduced on a commercial scale by Exxon Chemical in 1961. 

The nucleophilic curing system is most common and is used in about 80% of all applications. It is based on the cross-linker (bisphenol AF) and accelerator (phase transfer catalyst, such as phosphonium or amino-phosphonium salt). Both diaminic and bisphenol type cure systems are permitted by U.S. Food and Drug Administration (FDA) regulations governing rubber articles in contact with food. The diaminic curing system is also used in some coating and extrusion applications [42]. 

GR-A Government Rubber—Acrylonitrile GR-I Government Rubber—Isobutylene GR-M Government Rubber—Monovinyl acetylene GR-P Government Rubber—Polysulphide GR-S Government Rubber—Styrene... 

Government Rubber Styrene. General-purpose synthetic rubbers that were originally produced in government owned plants as GR-S. They are copolymers obtained by the polymerization of butadiene and styrene in a ratio of approx 3 1. The chains contain a random sequence of the two monomers. Very similar in composition to Buna S, bra ton, Sol-p re pie, Stereon. Review P. Schneider el at., in Ullmann,... 

---