Extraction and characterization of natural colorant from Melia azedarach bark and its utilization in dyeing and finishing of wool

Abstract

Melia azedarach has a long history of use in furniture production in China. However, its by-product Melia azedarach bark (MAB) and its application as a natural colorant for textiles have not been fully exploited. Increasing awareness of environmental protection and health has led to an increase in the utilization of natural dyes from agricultural and forestry bio-products. This paper focuses on the extraction and application of MAB as a novel natural functional colorant for wool fabrics. Three different solvents (ethanol/water, water with acid or alkali, and ethanol/water with alkali) were used. The chemical composition of the different MAB extracts, the color characteristics, colorfastness, and functional properties of MAB dyed wool fabrics by different dyeing methods were investigated in this work. The extraction solvent of 40% ethanol/water with alkali gave the maximum crude yield of 18.9%. Wool fabrics dyed directly or pre-mordanted with Al3+ and Fe2+ salts showed various hues with acceptable colorfastness to laundering, crocking, and light, as well as functional properties such as UV protection, fluorescence, and anti-moth. MAB extracts proved to be a desirable natural colorant and the dyed wool fabrics proved to be high value-added.