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Thermal cis-trans isomerization and photofading of some azo dyes in poly(ethylene terephthalate) matrices: A kinetic study

✍ Scribed by Ernestina Dubini-Paglia; Pier Luigi Beltrame; Bruno Marcandalli; Paolo Carniti; Alberto Seves; Loredana Vicini

Publisher: John Wiley and Sons
Year: 1986
Tongue: English
Weight: 535 KB
Volume: 31
Category: Article
ISSN: 0021-8995
DOI: 10.1002/app.1986.070310510

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✦ Synopsis

The thermal cis-trans isomerization of azo dyes XC6H4N=NC6H4N(C2H5)2 (where X is H, OCH3, CN, and NOz) in poly(ethy1ene terephthalate) matrices, below the glass transition temperature, and in dibutylphthalate solutions has been studied kinetically in the temperature range 20-60°C. Kinetic behavior in the polymer is characterized by two or three simultaneous first-order processes with similar activation enthalpies. These processes reflect an unequal distribution of "tie-molecules," "folds," and "cilia" in the amorphous region of the polymer. Lightfastness of the dyes in poly(ethy1ene terephthalate) films has been investigated. Polymer morphology strongly affected the photofading, but no significant influence was observed in the kinetic experiments.

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