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Photofading of phenylazo‐aniline, ‐pyridone and ‐quinolone disperse dyes on a nylon 6 substrate
Author(s) -
Okada Yasuyo,
Hihara Toshio,
Morita Zenzo
Publication year - 2009
Publication title -
coloration technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 1472-3581
DOI - 10.1111/j.1478-4408.2009.00179.x
Subject(s) - chemistry , aniline , radical , nitro , photochemistry , disproportionation , hydroxide , nitroso , inorganic chemistry , medicinal chemistry , organic chemistry , alkyl , catalysis
The photofading of phenylazo‐aniline, ‐pyridone and ‐quinolone disperse dyes on nylon fabric was analysed using the Kubelka–Munk ( K / S ) spectra of fabrics exposed to a carbon arc in air. The exposure of dyed fabric through ultraviolet and coloured filters, which do not shield the main absorption band, showed a large decrease in the initial rate ( K PA ) of fading. Compared with the K PA values without filters, the values using filters were half as large for dyes without the nitro groups and a quarter as large for dyes with the nitro groups. The K PA values may be qualitatively explained by the sum of azo scission (decrease of K / S value at λ max ) and the conversion of nitro groups to nitroso groups. These phenomena occur, respectively, via thermal disproportionation reactions between hydrazinyl radicals (from the azo group) and the reaction between hydrazinyl and N‐centred nitrosyl hydroxide radicals (from the nitro group). The azo scission is promoted by N‐centred nitrosyl hydroxide radicals via the latter reactions.