Investigation of pH influence on madder-dyed cotton blends

Abstract

The study aimed to optimise the dyeing pH of Banana/Cotton and Bamboo/Cotton blended fabrics using natural madder dye. In this study, eight fabric samples are dyed under varying pH conditions (pH 7–10) using madder dye extracted through an aqueous process. Punica granatum peel is employed as a natural mordanting agent for all samples. The Banana/Cotton blend exhibits the highest colour strength at pH 9 (K/S = 24), while the Bamboo/Cotton blend shows maximum colour strength at pH 10 (K/S = 26). SEM analysis of the optimised dyed samples reveals distinct surface modifications, while FTIR spectra confirm chemical changes among raw, mordanted, and dyed fabrics. Colour fastness to rubbing, washing, and light exposure is found to range from good to excellent. All madder-dyed fabrics demonstrate higher antimicrobial activity than their undyed counterparts, with the Bamboo/Cotton blend exhibiting superior antimicrobial performance compared with the Banana/Cotton blend.