The Nature of Azo Dye Light Fading in Polyester and the Physical State of the Dye

Abstract

A series of azo compounds based on benzeneazo-β-naphthol were applied to polyester film by dyeing from dispersions, and their fading rates were determined. From the relation between the electron-attracting or withdrawing properties of the substituents in the benzene nucleus and the relative fading rates, it is concluded that the fading reaction is oxidative. This conclusion agrees with that from earlier analyses of fading products of anthraquinone disperse dyes on polyester. It is therefore clear that polyester conforms with the general rule that fading on any nonprotein is oxidative, provided that oxygen has access to the dye. The shape of the fading rate curves in the present experiments indicates that the dyes are present in the polyester at least partly as aggregates.

The linear curve of relative fading rate vs. the Hammett σ-value of the substituent in the benzene nucleus has a lower slope than that for the same dyes on polypropylene. It is suggested that the polar nature of the substrate reduces the influence of a substituent group on the reactivity of the active center (the azo group) in the dye molecule.

Get full access to this article

View all access options for this article.

References

Ahmed

Mallet

, Fading of Azo Dyes and Pigments on Polypropylene, J. Soc. Dyers Colour. 84, 313–314 (1968).

Atherton

Seltzer

, Some Studies of the Fading of Simple Monoazo Dyes, J. Soc. Dyers Colour. 65, 629–638 (1949).

Atherton

Peters

R. H.

, Some Further Investigations into the Fading Rates of Monoazo Dyes, J. Soc. Dyers Colour. 68, 64–66 (1952).

(a) Blaisdell

B. E.

, The Photochemistry of Aromatic Azo Compounds in Organic Solvents, J. Soc. Dyers Colour. 65, 618–628 (1949).

Charton

Marvin

, The Application of the Hammett Equation to ortho-Substituted Benzene Reaction Series, Canadian J. Chem. 38, 2493–2499 (1960).

Chipalkatti

H. R.

Desai

N. F.

Giles

C. H.

Macaulay

, The influence of the Substrate upon the Light Fading of Azo Dyes, J. Soc. Dyers Colour. 70, 487–501 (1954).

Cumming

J. W.

Giles

C. H.

McEachran

Miss A. E.

, A Study of the Photochemistry of Dyes on Proteins and other Substrates, J. Soc. Dyers Colour. 72, 373–381 (1956).

Giles

C. H.

, The Light Fastness of Dyed Fibres—A Statistical Study, J. Soc. Dyers Colour. 73, 127–160 (1957). For corrections see ref. [10].

Giles

Charles Hugh

, “A Laboratory Course in Dyeing,” Soc. Dyers Colourists, Bradford, England, 3rd edn., 1974.

10.

Giles

Charles H.

Hojiwala

Balvantrai J.

Shah

Champaklal D.

Sinclair

Roy S.

, Activation Energies of Light Fading of Non-ionic Disperse Dyes in Hydrophobic Polymers, J. Soc. Dyers Colour. 90, 45–49 (1974).

11.

Giles

Charles H.

Johari

Devendra P.

Shah

Champaklal D.

, Some Observations on the Kinetics of Dye Fading, Textile Res. J. 38, 1048–1056 (1968).

12.

Giles

C. H.

Shah

C. D.

Watts

W. E.

, Oxidation and Reduction in Light Fading of Dyes, J. Soc. Dyers Colour. 88, 433–435 (1972).

13.

Giles

C. H.

Sinclair

R. S.

, Photodecomposition of Aminoanthraquinone Disperse Dyes on Poly(ethylene terephthalate), J. Soc. Dyers Colour. 88, 109–113 (1972).

14.

Hammett

L. P.

, “Physical Organic Chemistry,” McGraw-Hill Book Co., New York, 1940, Chap. VII.

15.

Johnson

R. F.

Stamm

O. A.

Zollinger

Hch

, Zusammenhang der Konstitution Kationisher Triphenylmethanfarbstoffe mit ihrer Lichtechtheit auf Polyacrylnitrilfasern, in “Optische Anregung organischer Systeme” (2 Internat. Farbensymposium) (Pappelallee, Germany: Verlag Chemie, 1967), pp. 375–390.

16.

Kienle

R. H.

Stearns

E. I.

van der Meulen

P. A.

, A Correlation of Structure with Fastness to Light of Monoazo Dyes, J. Phys. Chem. 50, 363–372 (1946).

17.

Ohtsu

Nishida

Nagumo

Tsuda

, Aggregation of Crystals of Acridine Orange (C. I. Basic Orange 14) in Various Synthetic-polymer Fibres, Coll. and Polym. Sci. 252, 377–380 (1974).

18.

Warwick

G. P.

, Relative Rates of Reduction of a Series of Azo Compounds, J. Soc. Dyers Colour. 75, 291–299 (1959).