Sage Journals: Discover world-class research

Abstract

Ultraviolet absorption and fluorescence spectroscopy have been used to determine the nature and extent of photo-decomposition of fluorescent whitening agents in polymer films and in surface-whitened wool. Irradiation of the coumarin (I) in polymer films at 365 nm gives rise to a mixture of photodimers which rapidly revert to I on irradiation at wavelengths less than 320 nm. Irradiation of the stilbene (II) at 365 nm also gives a photodimer which absorbs strongly around 350 nm, but this reverts only slowly to II on irradiation.

Fluorescence studies indicate that there is an increase in the degree of aggregation of I in polymer films with increasing whitener concentration, and that the kinetics of whitener photodecomposition change from first-order at low whitener concentration (0.0025%) to second-order at the higher concentration (2.5%) used in surface-whitening. The coumarin (I) is more stable to light in poly(vinyl acetate) film cast from formic acid than in films cast from less polar solvents, probably because of differences in the degree of whitener aggregation. The photostability of I in poly(vinyl acetate) film is also improved if the film is heated for short periods or stored at room temperature for longer periods.

Get full access to this article

View all access options for this article.

References

1. Bregman

Osaki

Schmidt

G. M. J.

Sonntag

F. I.

, Topochemistry. Part IV. The Crystal Chemistry of some cis-Cinnamic Acids, J. Chem. Soc., 2021–2030 (1964).

2. Cohen

M. D.

Schmidt

G. M. J.

, Topochemistry. Part I. A Survey, J. Chem. Soc., 1996–2000 (1964).

3. Cohen

M. D.

Schmidt

G. M. J.

Sonntag

F. I.

, Topochemistry. Part II. The Photochemistry of some trans-Cinnamic Acids, J. Chem. Soc., 2000–2013 (1964).

4. Giles

C. H.

McKay

R. B.

, The Lightfastness of Dyes: A Review, Textile Res. J. 33, 528–577 (1963).

5. Graham

D. R.

Statham

K. W.

, The photochemical Oxidation of Wool in the Presence of Fluorescent Compounds, J. Soc. Dyers Colourists 72, 434–438 (1956).

6. Green

A. E. S.

Sawada

Shettle

E. P.

, The Middle Ultraviolet Reaching the Ground, Photochem. Photobiol. 19, 251–259 (1974).

7. Hammond

G. S.

Stout

C. A.

Lamola

A. A.

, Mechanisms of Photochemical Reactions in Solution. XXV. The Photodimerization of Coumarin, J. Am. Chem. Soc. 86, 3103–3106 (1964).

8. Hausermann

, 7-Triazinylamino-3-phenylcoumarins, U. S. Patent 2945033 (July 12, 1960); Chem. Abstr. 55, 3082–3084 (1961).

9. Hida

Kodaira

Yamada

Yabe

, Light Fading of Dyes. V. Kinetic Consideration of Photofading of Fluorescent Brightening Agents, Nippon Kagaku Kaish (10), 1906–1913 (1972).

10.

10. Hirt

R. C.

Schmitt

R. G.

Searle

N. D.

Sullivan

A. P.

, Ultraviolet Spectral Energy Distribution of Natural Sunlight and Accelerated Test Light Sources, J. Opt. Soc. Amer. 50, 706–713 (1960).

11.

11. Holt

L. A.

Milligan

Wolfram

L. J.

, Fluorescent Whitening Agents. Part VI: The Whitening of Wool by Surface Application of Whitener/Polymer Solutions, Textile Res. J. 45, 257–264 (1975).

12.

12. Leaver

I. H.

Milligan

Holt

L. A.

, Fluorescent Whitening Agents. Part VII. Photodimerization of a Naphthotriazolylstilbene Derivative, Aust. J. Chem. 29, 437–442 (1976).

13.

13. Leaver

I. H.

Ramsay

G. C.

, Studies in Wool Yellowing Part XXVI: Photoyellowing of Fluorescent-Brightened Wools—Wavelength Dependence and ESR Studies, Textile Res. J. 39, 722–729 (1969).

14.

14. Leaver

I. H.

Ramsay

G. C.

, Sensitized Photo-Oxidation of Wool and Silk by a Triazinylstilbene, Photochem. Photobiol. 9, 531–536 (1969).

15.

15. Leenders

L. H.

Schouteden

De Schryver

F. C.

, Photochemistry of Nonconjugated Bichromophoric Systems. Cyclomerization of 7,7‘-Polymethylenedioxycoumarins and Polymethylenedicarboxylic Acid (7-Coumarinyl) Diesters, J. Org. Chem. 38, 957–966 (1973).

16.

16. Libermann

Desnoës

Hengl

, 7-Nitro- and 7-Aminocoumarins, C. R. H. Acad. Sci. 232, 2027–2029 (1951).

17.

17. Milligan

Holt

L. A.

Leaver

I. H.

, The Surface-Whitening of Wool: Factors Affecting the Photostability of Fluorescent Whitening Agents in Polymer Films, Int. Wool Textile Res. Conf., 5th, Aachen, 1975, in press.

18.

18. Mustafa

Kamel

Allam

M. A.

, Dimerization Reactions in Sunlight. V. Photodimerization of Substituted Coumarins, J. Org. Chem. 22, 888–891 (1957).

19.

19. Schmidt

G. M. J.

, Topochemistry. Part III. The Crystal Chemistry of some trans-Cinnamic Acids, J. Chem. Soc., 2014–2021 (1964).

20.

20. Rao

N. V. Subba

Sundaramurthy

, Search for Physiologically Active Compounds. V. Synthesis of Nitrocoumarins, Proc. Indian Acad. Sci. A 54, 321–324 (1964).

21.

21. Umemoto

Kitao

Konishi

, Fluorescent Whitening Agents for Synthetic Fibres. XV. Photochemical Reaction of Fluorescent Whitening Agents of the Coumarin Type, Kogyo Kagaku Zasshi 73, 2200–2204 (1970).

22.

22. Umemoto

Watada

Fukushima

Matsuoka

Kitao

Konishi

, Photofading Reactions of Dyes. III. Photofading of Some Coumarins, Kogyo Kagaku Zasshi 74, 2333–2337 (1971).

23.

23. Yabe

Giles

C. H.

Hayashi

, Anomalous Fading of Dispersed-Type Fluorescent Brightening Agents—Fading on Film Substrates, Kogyo Kagaku Zasshi 72, 258–261 (1969).