Natural dyes in the design of textile: how to make them more competitive face to synthetic dyes

Abstract

In recent years, much attention has been focused on research to replace synthetic dyes, in a competitive manner, with natural dyes. In this work the dyeing of cotton fabric by using natural dyestuffs extracted from hibiscus, annatto, turmeric, coffee and acai berry has been studied in both magnetic stirring and ultrasonic extractions. Unlike the current literature results, the comparative values of extraction yield were found to be higher using magnetic stirring than ultrasound. Extraction medium and temperature seem to be predominant parameters on the extraction yield and dyeing performance. From the preliminary results obtained in this study, it might be suggested that, in general, it is possible to improve the performance of natural dyes on cotton fabrics when the extraction is carried out in alkaline medium at temperatures above 40 °C. An illustrative chart of the studied natural dyestuffs was assembled.