Styrene Butadiene and Polybutadiene

Krishen [119] has described a procedure for the determination of these monomer units. He quantitatively analysed the gaseous pyrolysis products from natural rubber, styrene-butadiene rubber and ethylene-propylene diene terpolymer rubber by gas chromatography. He showed that the 2-methyl-2-butene peak was linear with the natural rubber content of the sample. Styrene-butadiene rubber was determined from the peak area of the 1,3-butadiene peak. The ethylene-propylene-terpolymer content was deducted from the 1-pentane peak area of the pyrolysis products. Some of the pyrolysis products identified are shown in Table 4.10. 

Near-infrared spectroscopy has been used to determiners cis-1,4, trans-, A, and 1,2 butadiene groups in these polymers [120]. 

Miller and co-workers [121] used near-infrared spectroscopy to determine the microstructure and composition of polybutadiene and styrene-butadiene copolymers. The procedure was capable of distinguishing between ds-1,4, trans-l,A, and 1,2 butadiene groups. Geyer [122] has given details of a Bruker Spectrospin P/ID.28 used for the identification of plastics using mid-infrared spectroscopy. 

Pandey and co-workers [123] describe a novel approach to the non-destructive evaluation of various physicomechanical properties of propylene copolymer. A single-step measurement of the infrared spectrum followed by chemometric operation of the predetermined characteristic region of the spectrum enables one to obtain various property parameters of melt flow index, impact and flexural modulus, required for quality evaluation of the copolymer. 

Cheng and co-workers [124] determined bromobutyl isomers and isoprene in bromobutyl rubbers by IR spectroscopy. 

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Overall an elastomer may be defined as a natural or synthetic material that exhibits the rubberlike properties of high extensibility and flexibility. It identifies any thermoset elastomer (TSE) or thermoplastic elastomer (TPE) material. Such synthetics as neoprene, nitrile, styrene butadiene, and polybutadiene are grouped with natural rubber (NR) that are TSEs. The term s rubber and elastomer are used interchangeably. 

They ranked behind only styrene-butadiene, carboxylated styrene-butadiene, and polybutadiene rubbers in consumption in 1988. Worldwide capacity, exclusive of formerly Communist producers, has been reported as 1.47 billion lb. Of this, 40 percent is that of five producers in the United States. " ... 

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