Characteristics of the pyrolysis patterns of styrene-butadiene rubbers with differing microstructures

The pyrolysis patterns of styrene-butadiene rubbers (SBR) with different microstructures were characterized with pyrolysis-gas chromatography. SBRs with different content ratios of the styrene, 1,2, cis-1,4-, and trans-1,4-units were used. The major pyrolysis products were butadiene, 4-vinylcyclohexene (4-VCH), and styrene. The relative abundance of the styrene peak increased with an increase in the styrene unit in SBR. Variation of peak intensity ratios between the major pyrolysis products with the microstructure was investigated. Variation of the peak intensity ratio of 4-VCH/butadiene with the butadiene component content showed a specific trend. When the concentration of one component was nearly constant, the 4-VCH/butadiene ratio decreased with an increase in the 1,2-unit content while it increased with an increase in the cis-1,4- or trans-1,4-unit. This was explained by the specific pyrolysis pattern of the 1,2-unit. (C) 2002 Elsevier Science B.V. All rights reserved.