Functionalization of Jute to Improve Colour Yield and Fastness of Annatto Dye

Jute being an agro-renewable lignocellulosic bast fibre grown in India is mostly used in packaging applications. Functional treatments can impart value addition to the fibre for diversified applications. An endeavour was undertaken to dye jute with a natural colourant as well as to improve its antimicrobial and UV-resistance performance in the present work. Here, the jute fabric is dyed with the aqueous extract of annatto seeds after being mordanted with alum, tannic acid and stannous chloride. All these three mordants were applied on the jute fabric by padding method followed by drying in air. Mordants were applied on jute fabric individually as well as in the sequential application for dual mordanting using alum + SnCl2 and alum + tannic acid. The dyed samples were evaluated on the basis of colour strength and fastness parameters as well as their functionalized properties in terms of bacterial reduction per cent and UPF-values were evaluated. After examining the colour strength, the dyeing process variables were optimized. Wet and rubbing fastness values were found to be moderate. Jute fabrics were treated with chitosan biopolymer (0.5%, 1%, 1.5% and 2% o.w.f) and N-cetyl-N'-trimethylammonium bromide (CTAB) (1% and 2% o.w.f) to improve the wash fastness. Chitosan and CTAB improved the fastness of the dyed jute fabrics by ½ to 1 grade. Benzotriazole improved the light fastness of the dyes by 1 grade and upgraded the ultraviolet protection property of the dyed jute fabric significantly. The antimicrobial property of the dyed jute fabrics was also improved with annatto and with chitosan. Jute fabric dual-mordanted with alum and tannic acid achieved better colour strength, light fastness and UPF values than the one dual-mordanted with alum and stannous chloride.