ISSN:
0887-6266
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Further thermoluminescence data are presented supporting our earlier suggestion that the electron traps associated with the three peaks in the thermoluminescence glow curve of a low-density polyethylene sample from which absorbed air has been removed are formed by the polymer chains themselves in the chain-fold regions of the samples. These traps are shown to be sensitive to heating of the sample to temperature around its melting point; in particular, the lowest temperature peak disappears if the sample is held at 90°C in vacuum for 5 min. If the sample is maintained in vacuum at room temperature after such treatment, its modified glow curve remains unchanged for a period of at least 7 days; however, if the sample is exposed to air, nitrogen, or argon after such treatment, its gas-free glow curve begins to change within 3 days, evolving toward a three-peak form with the same peak temperatures but with relative intensities different from those observed before heating began. This suggests that the gas molecules “lubricate” the polymer chains, which then begin to move toward new equilibrium configurations. Immersion in n-hexane at room temperature has little effect on the luminescence centers but disables the electron traps. Immersion in fuming nitric acid at room temperature for 2 days appears to destroy the electron traps permanently, as would be expected if the chain folds are digested by the acid; its effect on the luminescence centers is still to be determined.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1987.090250908
