Radiation induced degradation of elastomers.

ADDY, S. W. (1987). Radiation induced degradation of elastomers. Doctoral, Sheffield Hallam University (United Kingdom)..

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Abstract

An attempt has been made to evaluate the kinetics of the thermal and combined thermal/radiative degradation of a peroxide cured polydimethylsiloxane elastomer (PDMS), and a vinylidene fluoride-hexafluoropropylene elastomer (Viton E60-C),by chemical stress relaxation measurements. It was observed that the PDMS elastomer degraded thermally by hydrolytic scission of the main chain and chain reformation by condensation of the silanol chain end groups. However,predominant chain reformation was observed during thermal degradation studies and it was believed that this was a consequence of the reformation of chains cut during the test,and also the reformation of chains cut prior to the test in the post cure operation. These two components of the observed chain reformation response were subsequently rationalized by a model. Thermal degradation of the Viton E60-C elastomer appeared to take place by hydrolytic scission of the amine crosslinkages, and subsequent crosslink reformation by condensation,indicating that the material had not been subjected to a suitable post cure treatment in order to remove water generated by the vulcanization reaction. At temperatures above 200°C predominant crosslinking was observed and this was attributed to the presence of a concurrent reaction which leads to the formation of ring structures. Thermal/radiative degradation studies indicated that temperature and radiation had a synergistic effect on the overall rate of induced chain scission in the PDMS elastomer but the mechanisms responsible for this phenomenon have yet to be established.

Item Type: Thesis (Doctoral)
Additional Information: Thesis (Ph.D.)--Sheffield Hallam University (United Kingdom), 1987.
Research Institute, Centre or Group: Sheffield Hallam Doctoral Theses
Depositing User: EPrints Services
Date Deposited: 10 Apr 2018 17:18
Last Modified: 10 Apr 2018 17:18
URI: http://shura.shu.ac.uk/id/eprint/19200

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