Self-Cleaning Leather A New Methodology for Photocatalyst Immobilization on Bovine Leather
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Abstract
This work evaluated the use of polycarboxylic acids as chemical binders to immobilize TiO2 to produce “crust” vegetable-tanned leather with self-cleaning properties. A methodology was developed with immersion of leather samples in a solution of polycarboxylic acids, followed by curing of the binder. Subsequently, photocatalyst deposition was performed through immersion, followed by a second curing process. Additionally, the samples were subjected to a wind tunnel to remove TiO2 layers overlapping the chemically bonded layer on the surface. To evaluate photocatalytic activity, a methylene blue photocatalyst activity indicator ink (PAII) was applied on the leather surface, being reduced by UV light. Photodegradation was registered through digital images and evaluated by RGB spectra. This methodology has never been used before for leather samples. Results showed that polycarboxylic acids acts like binder to collagen fibers through esterification reaction. Furthermore, it was found that increasing the photocatalyst cure temperature enhances the bonding between the carboxylic groups of succinic acid and TiO2, thereby increasing the photocatalytic activity. However, there is a temperature limit (60°C) above which the leather loses its properties.
These results demonstrated that the methodology was efficient, being able to produce self-cleaning vegetable-tanned leather with photocatalytic activity and good reproducibility.