The Mechanism of the Photochemical Degradation of Textile Material

Abstract

The photochemical degradation of textile materials is discussed under two main heads— I. PHOTOLYTIC DEGRADATION WITH Short‐WAVE ULTRA‐VIOLET RADIATION‐ The degradation of cotton and other textile fibres with radiation of wavelength 2537 A. is not dependent upon the presence of oxygen in the surrounding atmosphere. In some cases (e. g. cotton and visoose rayon) the loss in strength in carbon dioxide or nitrogen is nearly as great as in oxygen; in other cases (e. g. nylon) there is greater degradation in oxygen, but still substantial degradation in carbon dioxide. The effect of vat dyes on the rate of degradation of cotton is discussed. All the vat dyes examined were found to desensitise the photolytio degradation of cellulose. Dyes such as Caledon Yellow 5G and Cibanone Yellow R decreased the degradation of cotton in atmospheric air, dry oxygen, and inert gases. II. PHOTOCHEMICAL OXIDATION WITH NEAR ULTRA‐VIOLET AND VISIBLE LIGHT‐ The photochemical degradation of cotton and other textile fibres by light transmitted through glass is increased by various dyes and pigments. The sensitising dyes may belong to the following classes‐ vat, acetate, direct cotton, basic, acid, and sulphur; the pigments include zinc oxide, zinc sulphide, and titanium dioxide. The degradation of the various textile fibres is dependent upon the presence of oxygen in the surrounding atmosphere and is negligible in its absence. The mechanism of the degradation is discussed, and the evidence for the suggestion that the degradation is due to oxidation of the fibre by activated oxygen and hydrogen peroxide is examined. Evidence is described which favours the belief that activated oxygen is a metastable form of molecular oxygen.

Photo-induced growth of silver nanoparticles using UV sensitivity of cellulose fibers

“…Each site might be a cellulose monomer (a glucose ring) that forms aldehyde groups upon photon absorption [30,31]. When cellulose is irradiated by UV, the oxygen bonding between the glucose rings will break and form an aldehyde agent that could reduce Ag + ions.…”

Evidence for the Participation of Singlet Oxygen in the Vat–dye Photosensitized Degradation of Cellulose

“…Another theory has been described by Egerton [4] who, in 1949, suggested that the intermediate was some form of activated oxygen similar to that postulated by Kautsky, [ 5 ] , some years before.…”

Effect of pH on the Dye Absorption of Jute Fibre Dyed with Direct Dyes

“…The possible explanation is that the raw jute contains high amount of lignin than bleached jute fibre. The exposed dyes gain sensitivity action on photooxidation process which is initiated by lignin in presence of light and it causes the rapid change in colour of dyed fibre 15 . Wash fastness It is seen from the Table 3 that the wash fastness of Direct Orange 31 dyed jute fibre exhibits good.…”

“…It is seen from the Table 5 that the loss in breaking strength of dyed raw jute is comparatively higher than that of dyed bleached jute. This is due to the presence of higher lignin in raw jute 15 .…”