Study on thermal degradation of polystyrenes by pyrolysis-gas chromatography and pyrolysis-field ionization mass spectrometry

✍ Scribed by H. Ohtani; T. Yuyama; S. Tsuge; B. Plage; H.-R. Schulten

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 396 KB
• Volume: 26
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(90)90164-y

✦ Synopsis

The mechanism of the thermal degradation of polystyrene was studied by pyrolysis-gas chromatography and pyrolysis-field ionization mass spectrometry, using a block copolymer of ordinary and perdeuterated styrene [poly(styrene-b-styrene-ds) ]. The main degradation products were monomers, dimers and trimers of the styrenes. Quite large amounts of hybrid dimers of styrene and styrene-ds units were formed as well as the homo-dimers of the two types of units in the block copolymer, whereas formation of hybrid trimers was negligible. The principal hybrid dimers were CD~---C(C6Ds)CD2CH2(C6Hs) and CH~---'C(C6Hs)CH2CD2(C6D5), and their yields were comparable with those of the homo-dimers. These results suggest that the dimers are primarily formed through the reactions of unsaturated chain-ends and benzyl radicals which are generated by 1,5-transfer of the secondary macroradical followed by fl-scission. On the other hand, dimer formation through 1,3-transfer, as proposed by many authors, was confirmed not to be the main pathway to the dimers.