Cationic pretreatment of cotton and dyeing with Fallopia japonica leaves

Abstract

This work examines the possibility of using leaves from the invasive plant species Fallopia japonica (Japanese knotweed) as a source of dye for the natural dyeing of cotton. To achieve a higher uptake of extracted dye, a cationic agent instead of a classical mordant was used to treat the cotton prior to dyeing. Distilled water and 0.5 M NaOH were used as extraction mediums to produce natural dyebaths with diff erent concentrations (10, 20 and 50 g/L) of Fallopia japonica leaves. The colorimetric measurements revealed that a higher concentration of extract, the extraction of leaves in NaOH and a cationic pretreatment of cotton yield a dark-brown-coloured cotton with good wash stability.