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Photophysical processes in poly(hexamethylene adipamide)–acid dye complexes: Energetics of nylon 66 phototendering
Author(s) -
Koenig H. Steve,
Roberts Carleton W.
Publication year - 1975
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.1975.070190707
Subject(s) - photochemistry , triplet state , chromophore , polyamide , quenching (fluorescence) , nylon 6 , chemistry , excited state , anthraquinone , materials science , polymer chemistry , fluorescence , organic chemistry , polymer , molecule , physics , quantum mechanics , nuclear physics
The mechanism of dye‐sensitized photo‐oxidative degradation of nylon 66 was investigated. A known phototendering dye, C.I. Acid Blue 40 (1‐amino‐4‐( p ‐aminoacetanilide)‐2‐anthraquinone sodium sulfonate), was used for this study. Excitation and emission spectra of the dyed and undyed nylons indicated that a ground‐state complex between the dye and the polyamide was formed upon dyeing. The energy level of the complex's electronic states favor triplet–triplet energy transfer from the nylon to the complex. Quenching studies show that the energy transfer occurs efficiently with a rate constant of 45.8 l. mole −1 sec −1 . An additional energy transfer occurs between the excited free dye and the complex by either a singlet–triplet or a triplet–triplet mechanism. Kinetic analysis of the nylon‐complex energy transfer suggests that the triplet energy of nylon migrates 24 to 33 Å along the amide chromophores in an exciton fashion until an energy trapping complex is reached. Energy is then transferred by an exchange mechanism. Photo‐oxidative studies verify that the dye–nylon complex sensitizes the polyamide photo‐oxidative degradation at its own expense without dye photobleaching.