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Thermal cis – trans isomerization of 4‐diethylamino‐4′‐methoxyazobenzene in poly( D (−)3‐hydroxybutyrate) and its hydroxyvalerate copolymer as a probe for characterizing their aging
Author(s) -
DubiniPaglia Ernestina,
Castelli Antonella,
Beltrame Pier Luigi,
Seves Alberto,
Marcandalli Bruno
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070560814
Subject(s) - isomerization , polyester , copolymer , polymer , materials science , polymer chemistry , ethylene , kinetics , accelerated aging , chemistry , organic chemistry , catalysis , composite material , physics , quantum mechanics
The aging of bacterial polyester poly( D (—)3‐hydroxybutyrate) has been studied by coloring it with 4‐diethylamino‐4′‐methoxyazobenzene and determining the reduction in isomerization rate of the dye with aging, such a reduction being a measure of the loss in polymer sequential mobility that is responsible for the considered phenomenon. A preliminary test carried out on poly(ethylene terephthalate) colored with 4‐diethylaminoazobenzene proved the isomerization of the dispersed dye to be a sound probe for determining the aging process. In the case of the bacterial polyester, the aging process appeared even above the polymer T g value measured by calorimetric analysis. The kinetics and rate coefficients of aging were determined at 30°C for the examined polymers. Aging in the copolymer poly(hydroxybutyrate‐hydroxyvalerate) was also investigated. © 1995 John Wiley & Sons, Inc.