1. Azo dye location in textiles: a novel UV-vis approach.
- Author
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Oakes, John, Batchelor, Stephen N., and Dixon, Sarah
- Subjects
AZO dyes ,DYES & dyeing ,TEXTILES ,COLOR ,AZO compounds - Abstract
Ultraviolet-visible spectra of Orange II exhibit blue shifts in apolar solvents due to the formation of the azo tautomer. Upon absorption to cotton, Orange If remains as the hydrazone tautomer and, like other phenylazonaphthol dyes or Methyl Orange, exhibits small red spectral shifts Two superimposed spectra -- characteristic of the azo and hydrazone tautomeric forms - are detected when dye 1 (X = p-MeO) absorbs onto cotton Only the azo form is observed on nylon; all other dyes, except Orange II, give blue shifts. A model is developed in which the more apolar moiety of the dye binds to pockets formed in the non-crystalline (amorphous) regions of cotton, with those parts containing the sulphonate group protruding into aqueous pores. In nylon, the binding sites are more apolar with the sulphonate groups bound electrostatically. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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