Photocatalytic Finishing of Cotton Fabrics Based on Nano-Titanium Dioxide and Polyurethane Binder

Abstract

In the textile industry, binders are used in fabric finishing processes to promote adhesion between a fiber surface and the particles of desired properties. In this research, a commercial polyurethane binder, Evo®Fin PUS, was used to attach photocatalytic TiO2nanoparticles (Degussa®, P-25) onto a cotton surface, in order to impart self-cleaning properties and to improve wash fastness. The cotton fabrics were finished with the aqueous dispersion of TiO2and the binder, consisting of 2, 4, and 6 % w/v for each component. Finishing was done via a pad-dry-cure process. Then a direct dye (C.I. Direct Blue 199), which was used as a model stain, was dropped onto each sample prior to 24-h illumination with simulated solar light. The self-cleaning properties were triggered by light and evaluated in terms of the reduction in color strength values (K/S) of the stain after exposure. The self-cleaning performance was preserved when the binder was added to the TiO2coating. However, washing reduced the self-cleaning performance of all samples because of the detachment of some TiO2particles, as observed by scanning electron microscopy. Overall, improved wash fastness was observed with the help of binder. Samples were further analyzed for mechanical properties, crease recovery, and drapeability.