Buna

Emulsion polymerisation of a mixture of butadiene and styrene gives a synthetic rubber (Buna S GBS rubber), which is used either alone or blended with natural rubber for automobile tyres and a variety of other articles. 

By polymerising an emulsified mixture of butadiene and styrene (ca. 25 per cent.) Buna S or OBS rubber is produced ... 

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. 

Styrene-butadiene rubber (SBR) (also known as Buna S) 0.94 40-100 400-600 1600-3700 -60 107... 

Acceptable for exo if used with buna rubber plates and rollers. 

Bunawerke Huls GmbH Europe Buna Co-Z-N, Ti-Z-N, Nd-iaie... 

Bunawerke Huls GmbH Europe Buna Li—alkyl... 

Vinyl level foi Buna and Intolene, medium—high Budene, medium and Nipol and Polysai VBR, high. 

Sodium is a catalyst for many polymerizations the two most familiar are the polymerization of 1,2-butadiene (the Buna process) and the copolymerization of styrene—butadiene mixtures (the modified GRS process). The alfin catalysts, made from sodium, give extremely rapid or unusual polymerizations of some dienes and of styrene (qv) (133—137) (see Butadiene Elastomers, synthetic Styrene plastics). 

In the late 1920s Bayer Company began reevaluating the emulsion polymerisation process of polybutadiene as an improvement over their Buna technology, which was based on sodium as a catalyst. Incorporation of styrene (qv) as a comonomer produced a superior polymer compared to polybutadiene. The product Buna S was the precursor of the single largest-volume polymer produced in the 1990s, emulsion styrene—butadiene mbber... 

Buna S styrene—butadiene good fair poor... 

Styrene—Butadiene Rubber (SBR). This is the most important synthetic mbber and represents more than half of all synthetic mbber production (Table 3) (see Styrene-butadiene rubber). It is a copolymer of 1,3-butadiene, CH2=CH—CH=CH2, and styrene, CgH5CH=CH2, and is a descendant of the original Buna S first produced in Germany during the 1930s. The polymerization is carried out in an emulsion system where a mixture of the two monomers is mixed with a soap solution containing the necessary catalysts (initiators). The final product is an emulsion of the copolymer, ie, a fluid latex (see Latex technology). 

Nitrile (Buna-N) is a rubber compound popular in most household plumbing applications. It s a basic plumbers o-ring seal, and handles most household liquids and chemicals. Because industry pumps so much water, this elastomer may be the single most popular o-ring seeondary seal in the world. Its service range is from -30° F to +250° F (-34° C. to +120 C). 

O-rings, especially Buna-N (Nitrile compound), should be stored away from fluorescent lighting and electric motors. These are sources of ozone. Ozone causes a general degradation of these elastomers. 

The process of anionic polymerisation was first used some 60 or more years ago in the sodium-catalysed production of polybutadiene (Buna Rubbers). Typical catalysts include alkali metals, alkali metal alkyls and sodium naphthalene, and these may be used for opening either a double bond or a ring structure to bring about polymerisation. Although the process is not of major importance with the production of plastics materials, it is very important in the production of synthetic rubbers. In addition the method has certain special features that make it of particular interest. 

Although first prepared about 1930 by scientists at the German chemical company of IG Farben the early products showed no properties meriting production on technical grounds. However, towards the end of the 1930s commercial production of the copolymer commenced in Germany as Buna S. (The term Buna arose from the fact that the early polymers of butadiene were made by sodium (Na) catalysed... 

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