Photo-oxidation poly(butadiene); quenching of excited states by nitroxides

✍ Scribed by J.S. Hargreaves; D. Phillips

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 526 KB
• Volume: 15
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(79)90195-2

✦ Synopsis

The phosphorescence from three model bicyclic enones and those formed in thermally oxidized poly{butadiene) has been shown to be quenched efficiently by a nitroxide [3,3,4.4-tetramethyldiaze-tine N,N'-dioxide] in CH2CI 2:tetrahydrOfuran glass at 77K. The Perrin model for static quenching was applied, and the interchromophoric distance for half-quenching found to be -12A. At room temperature the nitroxide additive inhibited the formation of volatile products from thermally oxidized poly(butadiene) films; results also obeyed the Perrin relationship, pointing to a quenching mechanism of photostabilization. By contrast, a commercial hindered amine stabilizer was found not to act as a quencher of phosphorescence at 77K, and to have a concentration dependence for the reduction in volatile product formation at 298K in PBD films different from the nitroxide, indicating different mechanisms of action.