Lignocellulose‐based <i>Stryphnodendron adstringens</i> bark as a natural dye source for textiles: Extraction and dyeing studies

Abstract Natural dyes are gaining interest as a more ecological approach to textile coloration, as well as for slow fashion and the bioeconomy. The use of local raw materials is a way of valuing small producers and recovering traditional knowledge. In this context, the current investigation was developed to study the use of lignocellulose‐based Stryphnodendron adstringens (Mart.) Coville (known as “barbatimão”) bark extract, from a native tree in Brazil, as a natural dye for textile dyeing. Physical–chemical analyses were performed on the reddish‐brown extract, the results of which showed an acidic pH and the likely presence of condensed tannins and flavanols. The optimised dyeing process was evaluated by a 2 3 factorial design. The fabrics dyed under optimised conditions were evaluated for colour fastness to laundering, rubbing, light and perspiration, and obtained good colour fastness ratings in most of these tests. Wastewaters from dyeings were characterised by physicochemical analyses. Because of the high turbidity and high biochemical oxygen demand and chemical oxygen demand levels, as well as the amount of residual metal ions from dyeing with mordants, the need for wastewater pretreatment was evident. Based on this research, S. adstringens extracts have significant potential for textile coloration.