Pyrolysis mass spectrometric analysis of styrene-isoprene-styrene copolymers

Abstract

Thermal analysis of styrene±isoprene±styrene block copolymer, using the direct pyrolysis mass spectrometry (MS) technique, indicated that each block showed very similar thermal behavior with the corresponding homopolymer. The isoprene block was found to be thermally less stable, decomposing by random scissions followed by cyclization reactions. The more stable styrene block degraded by a radical depolymerization mechanism. With an indirect pyrolysis MS technique, it was found that production of benzene, toluene, 1-methyl cyclopentene and 1-methyl cyclohexene was more e ective when degradation was carried out in a closed reactor. # 1999 Elsevier Science Ltd. All rights reserved.