Analysis of photofading of phenylazo-indole and phenylazo-N-ethanolaniline disperse dyes on poly(ethylene terephthalate) fabric using the PM5 method

摘要

The photofading behaviors of phenylazo-N-(ethanol)aniline and phenylazo-indole, nitrohetarylazo-N-substituted aniline disperse dyes on poly(ethylene terephthalate) (PET) substrate were analyzed using the Kubelka-Munk (K/S) parameters of the dyed fabrics exposed to a carbon arc in air. The initial experimental slopes (K_(PET)) of fading on PET were estimated from the time profiles of the K/S values at the λ_(max). The rates (k_(0,i)) of reaction of these dyes with ~1O2 were estimated by frontier orbital theory using the PM5 method. The photosensitivities (f_i) of the dyes were estimated from the K_(PET) assuming that the K_(PET) values are proportional to the product of k_(0,i) and ft. Dyes with small f_i values, irrespective of their k_(0,i) values, possess excellent lightfastness (LF), while dyes with larger f_i values possess poorer LF. The validity of estimating k_(0,i) values by the MO method was confirmed experimentally by analyzing the mutually photosensitized fading behaviors of combination dyeings.