STUDY OF NATURAL DYES: EXTRACTION, FUNCTIONAL PROPERTIES AND THEIR APPLICATIONS

Abstract

Textile industries provide economic boost to many countries in the world. However, it pollutes environment due to the usage of synthetic dyes in textile industries. Synthetic colors are made from petroleum, leaving human health and aquatic biodiversity at risk. Certain synthetic dyes are poisonous and carcinogenic by nature and therefore it should be replaced with more environmentally friendly colors. Natural dye extraction process is so complex, it is critical to assess the solubility of the natural dyes before beginning. Most of the researchers have reported that there have seven extraction methods. Those are aqueous extraction, solvent extraction enzymatic extraction, fermentation extraction, extraction with microwave & ultrasonic energy, supercritical fluid extraction, alkaline or acid extraction. Each extraction procedures have their own set of benefits and drawbacks are discussed in this review. ''Mordant" used to set the dye on fabrics. It enhances the color and help to improve the fastness of the dye. Even for the same natural dye, different types of mordants produce distinct colors. As a result, the final color, brightness & color fastness qualities are controlled not only by the dye itself but also by the mordants concentration expert management. Natural dyes are especially well suited and pleasant for the manufacture of high value green products, as well as for the environment as a whole. The majority of researchers have stated that the majority of natural colors have therapeutic value, that some can fight illness and inflammation. that others can improve blood circulation, and can protect the human body from UV radiation without harming. Thus, revival of natural dye application on textiles and summary of earlier researches on standardization of its method of extraction, mordanting, dyeing process variables, functional properties and even natural finishing, etc. have been elaborated organized manner in this review.