Eco-Friendly Dyeing of Pretreated Cotton Fabric Using a Natural Dye Extract from Erythrina abyssinica

Abstract

The increasing awareness of toxicity of synthetic dyes has considerably raised the demand for natural dyes. Retaining color fastness and strength of natural dyes on fabric is the main limitation in textile dyeing with natural dyes. In this study cotton fabric was pre-treated with aqueous tannic acid in order to enhance the fabric’s color fastness and strength of the natural dye. The untreated, treated and dyed cotton were characterized using Fourier-Transform Infrared spectroscopic analysis to confirm the modification of the cellulosic fiber. Different solvents were used to extract dye from Erythrina abyssinica plant and subjected to phytochemical quantification then used to dye cotton. The new FTIR peaks at 2646 cm−1and 1578 cm−1, which correspond to carbonyl (C=O) stretching mode and C=C stretching mode for aromatic ring, respectively, confirmed the modification and dyeing due to the attachment of the aromatic dye molecules to the cellulose structure. It was noted that modification of cellulose structure enhanced color strength and fastness. Mordanting with alum and ferrous sulfate using different methods formed variety of shades that ranged between light yellow to greenish yellow. Therefore, Erythrina abyssinica plant can be used as a source of natural dye for dyeing cotton fabric.

Keywords

• natural dye
• pre-treatment
• tannic acid
• mordanting
• fastness
• color strength