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Synthetic rubber (PBR, SBR)

Styrene Butadiene Rubber SBR  

  Used as rubber (elastomer), thermoplastic elastomer TPE  , tire  

Other names: Buna S, Ameripol Synpol, EuropreneKralex, Polysar, Plioflex Copo CarbomixNipol Solprene 


Monomer: Styrene & Butadiene 


Solvent: DMF or Dimethylformamide  

Density: 0.92-0.95 g / cm3 (Depending on styrenne percentage) 


Melting Temperature (Tm): does not melt in the cooked state. 


Glass Transmission Temperature (Tg): Between -13 ° C-13 ° C (Depending on the percentage of styrene) 

Hardness (Shore A): 50 to 90 

Polar or nonpolar state: Nonpolar 

Flammability characteristics (easy identification method): 


§ It burns in a flame and continues to burn after the flame has been removed. 


§The yellow flame is orange and slightly annoying. 


§There is a grayish-white smoke with carbon particles. 


§Does not drip in the flame. 
§ Gives the smell of urban gas. 


History and Production: 

The copolymer (copolymer) of styrene and butadiene, which has more than 50% of butadiene, is called SBR. The typical ratio of monomers is between 70% and 75% of butadiene to 25% to 30% of styrene, and if the styrene is above 50%, the product is highly plastic and is used to produce latex paints (latex). 

This polymer is defined as a high-performance, high-performance polymer, and it is the most consumable in the world, due to the availability of cheap and abundant raw materials, with a good price, and therefore the highest volume of production Also in the rubber industry. Over 70% of SBRs are consumed in the tire industry, especially the tire, 15% in mechanical parts and about 10% in latex form.  

Styrene Butadiene rubber was actually developed in Germany before World War II, but it was used extensively in the United States and Germany during the Second World War to replace the natural rubber that was captured by East Asia (Japan).  

The mechanical properties of SBR are lower than NR, and thus there is no crystalline stretch, and therefore it is weak. if it is reinforced with ash or other materials, it would be even weaker than its normal natural form.  



Styrene-butadiene rubber (SBR)  is classified into three main categories in terms of production and polymerization method:  


 Emulsion method: 

In this method, polymerization is done through free radicals, which is done in two warm and cold conditions. The product obtained from the cold method in the presence of oil, or in the presence of high friction soot oil, Lots of lines, narrow molecular distributions, high molecular mass, and processability are difficult. (Series 1500 (Type 1500)).  

The product obtained by the hot method is also highly branched and has a broad molecular mass distribution, good processability and higher vinyl 1 and 2 percent. (Series 1000 (Type 1000))