ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Long-lived trapped radicals produced during the photopolymerization of butane-1, 4-diol diacrylate (BDDA) were studied by EPR and ENDOR spectroscopy and their thermal decay was followed by EPR measurements at different temperatures (40-120 °C) for kinetic study. The EPR signal showed the superimposition of two different patterns, a three-line and a single-line spectrum. Both EPR patterns decayed following first-order kinetics in the investigated temperature range. Activation parameters of the decay were obtained. The EPR patterns were attributed to the same radical species situated in fluid and in cross-linked regions of the photopolymerized BDDA. Radicals of the latter kind undergo electron spin exchange strong enough to wash out the hyperfine splitting. The single-line width is mainly determined by electron spin dipole-dipole interactions. The ENDOR response is only of the matrix kind, typical of radicals in a solid phase. The present model was also compared with recent literature reports.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610050108
