ISSN:
0959-8103
Keywords:
macroradical decay
;
polycarbonate
;
methyl substitution
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The effect of chemical modification on free radical behaviour was investigated employing electron spin resonance in a pair of amorphous polymers, namely tetramethyl bisphenol A polycarbonate (TMPC) and bisphenol A polycarbonate (PC). The initial concentrations of free radicals, decay curves and decay kinetic characteristics are discussed using both free-volume data from our structural study by positron annihilation spectroscopy and dynamic data from dynamic-mechanical relaxation investigations in the literature. It was found that the initial concentrations of free radicals depend predominantly on free-volume structure, being higher for TMPC compared with PC due to a weaker cage effect. The extent of free-radical decay as well as the macroradical decay kinetic characteristics have been found to depend more on the internal dynamics than on different physical structures, in contradiction to our previous investigation of the polymer with the same chemical structure (PC), but different physical structures introduced by different mechanical and/or thermal treatment.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
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