ISSN:
0887-624X
Schlagwort(e):
poly(methyl methacrylate)
;
pyrene
;
pulse radiolysis
;
radical ion decay
;
ion recombination
;
fluorescence
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
A pulse radiolysis study of poly(methyl methacrylate) in the presence of pyrene has been carried out in the temperature range 100-295 K. The concentration of pyrene was changed from 10-3 to 10-1 mol dm-3. The absorption/emission spectra and kinetics of solute excited states and solute radical ions were investigated. It was found that pyrene excited states were formed as a result of their radical ion recombination in a time scale up to seconds. The decay of solute radical ions was influenced by photobleaching and can be described by a time-dependent rate constant. The activation energy of Py ions decay was temperature dependent and was equal to 35.7 and 1.2 kJ/mol for temperatures 〉Tγ and 〈Tγ, respectively, where Tγ ∼ 175 K represented the transition temperature responsible for γ-relaxation. The reaction mechanism was proposed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1209-1215, 1998
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
