Mechanism of radiation degradation of polyisobutylene

Bremner T., Hill D.J.T., O'Donnell J.H., Perera M.C.S. and Pomery P.J. (1996) Mechanism of radiation degradation of polyisobutylene. Journal of Polymer Science, Part A: Polymer Chemistry, 34 6: 971-984.

Author Bremner T.
Hill D.J.T.
O'Donnell J.H.
Perera M.C.S.
Pomery P.J.
Title Mechanism of radiation degradation of polyisobutylene
Journal name Journal of Polymer Science, Part A: Polymer Chemistry   Check publisher's open access policy
ISSN 0887-624X
Publication date 1996-04-30
Sub-type Article (original research)
Volume 34
Issue 6
Start page 971
End page 984
Total pages 14
Subject 2505 Materials Chemistry
2507 Polymers and Plastics
Abstract GC, GC/MS, GPC, and Solution NMR spectra were used to study the γ radiolysis of polyisobutylene (PIB) in vacuum to different total doses (0-900 kGy) and at different temperatures (77-423 K). NMR spectra show a large number of new resonances with relatively narrow line widths, and a variety of NMR techniques have been employed to determine and quantify the structures associated with these new resonances. Chemical shift assignments were made by comparison with those for small molecule model compounds and predictions based upon calculations according to several different schemes. Chain-end structures have been proposed that account well for the majority of the new resonances, all being the result of an initial chain scission reaction initiated by the radiation. These assignments support some previous proposals for the mechanism of radiation degradation of polyisobutylene and exclude others. For example, NMR provides no evidence for the formation of ethyl chain ends and some of the main chain unsaturated structures previously proposed. NMR also indicate that at higher doses the chain end products formed during initial stages undergo secondary reactions. GC/MS data show the formation of oligomers during irradiation, which may be due to a backbitting mechanism.
Keyword GC/MS
NMR
Polyisobutylene
Radiation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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Created: Tue, 05 Jul 2016, 13:49:03 EST by System User