Premium
Influence of polycaprolactam morphology on thermal cis–trans isomerization and photofading of azo dyes differently dispersed in it: A kinetic study
Author(s) -
DubiniPaglia Ernestina,
Beltrame Pier Luigi,
Marcandalli Bruno,
Seves Alberto
Publication year - 1990
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.1990.070410323
Subject(s) - isomerization , crystallinity , kinetics , polymer , materials science , glass transition , polymer chemistry , kinetic energy , thermal , chemistry , thermodynamics , organic chemistry , catalysis , composite material , physics , quantum mechanics
Two polycaprolactam films were prepared characterized by different crystallinity degrees, the free volume model being prevalent in the former and the pore model in the latter. They were colored with azo dyes XC 6 H 4 NNC 6 H 4 N(C 2 H 5 ) 2 (where X is H and COOH), the latter of which gives specific interactions with the polymer. The kinetics of the thermal cis–trans isomerization of these dyes has been studied below and above the glass transition temperature of the polymer ( T g ) in the range 20–80°C. In every case, the isomerization process was found to be the result of a multiplicity of first‐order reactions and the dependence on temperature exhibited a break at the T g value. Lightfastness of the dyes in the polymer matrices has been also investigated. The isomerization and fading kinetics are discussed in terms of polymer structural features as well as of the nature of the dye.