fluorescence --- textilní chemie

Most of the textile materials made for outdoor application purposes undergo photolytic and photo-oxidative reactions during exposure to solar UV radiation. These reactions which result in colour loss (or fading) are also problematic for warning clothes (highly visible clothes). Photostability of warning clothes (fluorescent materials) is essential for their practical application. Warning clothes are used to ensure the visibility of a person wearing them under limited visibility like firemen, policemen, road workers and pedestrians. An understanding of the durability and degradation of dye molecule in the fibre within specific environments such as under UV radiation is required to assist the warning clothes manufacturers and consumers in making correct decisions on materials. Performing such tests as colourfastness to light provides information on how much studied textiles are fading or degrading and allow one to determine if it is needed to use another material.The main goal of this study was to investigate the standard test methods for colourfastness to light, originally developed for non-fluorescent samples, if they are applicable or valid for fluorescent materials. This was done by studying the degradation behavior of fluorescent textile materials under accelerated ageing using ultramed UV metal halide lamp. The results of this study evaluated by the use of kinetic model, CIE colour difference calculations and curves showing fading confirm the validity of the standard methods used for fluorescent materials. Visual inspections were performed through comparison of change in colour of a test specimen with unexposed reference sample.

Warning clothing - study of fluorescenece fading in UV irradiation