An investigation of radiation-induced structural changes in nitrile rubber

Autor: James H. O'Donnell, Peter J. Pomery, M.C.S. Perera, D. J. T. Hill
Rok vydání: 1996
Předmět:
Zdroj: Journal of Polymer Science Part A: Polymer Chemistry. 34:2439-2454
ISSN: 1099-0518
0887-624X
DOI: 10.1002/(sici)1099-0518(19960915)34:12<2439::aid-pola18>3.0.co;2-9
Popis: The mechanism of radiation-induced structural changes in nitrile rubber with different acrylonitrile contents were investigated by ESR, NMR, and FTIR. To investigate new structures solid-state NMR methods had to be used due to crosslinking of the irradiated rubbers, and higher probe temperatures were used to obtain better resolution. The radicals generated on the acrylonitrile groups were found to abstract hydrogen from the adjacent butadiene units resulting in the formation of allylic radicals. These allylic radicals reacted to form intermolecular crosslinks and cyclisation. Cyclisation of the butadiene units were found to occur in the initial stages of the irradiation. Radiation yields of radicals increased with acrylonitrile content from 1.42, 1.58, to 2.42 for 18, 30, and 45% acrylonitrile rubbers. The radiation yields for intemolecular crosslinking were higher in rubbers with higher acrylonitrile contents, giving G values of 17.8, 21.3, and 24.5 for 18, 30, and 45% acrylonitrile rubbers, respectively. However, the crosslink clustering was found to be less in the rubbers with a higher acrylonitrile content.
Databáze: OpenAIRE
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