An ESR study of the gamma radiolysis of aromatic polyesters containing isomeric naphthalene links

Citation
Djt. Hill et al., An ESR study of the gamma radiolysis of aromatic polyesters containing isomeric naphthalene links, RADIAT PH C, 62(1), 2001, pp. 195-201
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
RADIATION PHYSICS AND CHEMISTRY
ISSN journal
0969-806X → ACNP
Volume
62
Issue
1
Year of publication
2001
Pages
195 - 201
Database
ISI
SICI code
0969-806X(200107)62:1<195:AESOTG>2.0.ZU;2-S
Abstract
Six polyesters were synthesised from 4,4 ' -oxy-bis(benzoyl chloride) and 1 ,4-, 1,5-, 1,6-, 2,3-, 2,6-, and 2,7-naphthalenediol isomers. The structure s of the polyesters were characterised by means of IR, inherent viscosities in tetrachloroethane (TCE), solutions at 303 K and thermal analysis. The g lass transition temperatures were in the range of 425-494 K by DSC thermal analysis. All of the polyesters were irradiated in an AECL Gammacell 220 un it at a dose rate of approximately 6.7 kGy/h to doses in the range of 0-15 kGy at 77 and 300 K. ESR spectroscopy was used to examine the radicals form ed during radiolysis and to measure their yields. The G-values for radical formation in the polyesters were found to be in the range 0.18-1.41 at 77 K and 0.19-0.78 at 300 K. At 77 K, up to 15% of the radicals formed on radio lysis were found to be photo-bleachable anion radicals. Annealing experimen ts were carried out in order to identify the neutral radicals, which were a ssigned to naphthyl- or phenyl- and phenoxyl-type radicals. (C) 2001 Elsevi er Science Ltd. All rights reserved.