Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 2, 2011
Previous Article Next Article

Revising the mechanism of polymer autooxidation

Author affiliations

Abstract

The basic scheme for autooxidation of polymers, originally developed by Bolland, Gee and co-workers for rubbers and lipids, is now widely applied to all types of polymeric materials. According to their scheme, the reaction that makes this process autocatalytic, referred to as the propagation step, is a hydrogen abstraction from the next substrate by the peroxyl radical (ROO˙ + RH → ROOH + R˙). In this study, using advanced quantum-chemical methods, we have shown that this step is actually characterised by largely positive Gibbs free energy (10–65 kJ mol−1) for most regular polymers with saturated chains (polypropylene, polyethylene, polyvinyl chloride, polyvinyl acetate, polyurethane, poly(methyl methacrylate)etc.) and even some polymers with unsaturated fragments (polystyrene, polyethylene terephthalate). Neither elevated temperature, nor solvation makes this process thermodynamically favourable. Only when the formed radical centre is conjugated with adjacent double bonds (as in polybutadiene) or captodatively stabilised by two suitable functional groups (such as a carbonyl and a lone pair donor such as oxygen or nitrogen), is the propagation step exoergic. Instead, we show that it is the presence of structural defects, such as terminal or internal double bonds, formed either during polymerisation or in the degradation process itself, that is responsible for the autooxidation of most polyesters and most polyalkenes. Recognition of the real mechanism of autooxidation in polymers is a key to developing strategies for the prevention of their degradation.

Graphical abstract: Revising the mechanism of polymer autooxidation

Back to tab navigation

Supplementary files

Article information


Submitted
18 Aug 2010
Accepted
29 Sep 2010
First published
11 Nov 2010

Org. Biomol. Chem., 2011,9, 480-490
Article type
Paper

Revising the mechanism of polymer autooxidation

G. Gryn'ova, J. L. Hodgson and M. L. Coote, Org. Biomol. Chem., 2011, 9, 480
DOI: 10.1039/C0OB00596G

Social activity

Search articles by author

Spotlight

Advertisements