Author: Ashis Kumar Samantaa & Priti Agarwal
Natural dyes are known for their use in coloring of food substrate, leather as well as natural protein fibers like wool, silk and cotton , characterization and chemical/biochemical analysis of natural dyes; extraction of colorants from different natural sources; effects of different mordants and mordanting methods; conventional and non-conventional methods of natural dyeing; physico-chemical studies on dyeing process variables and dyeing kinetics; development of newer shades and analysis of colour parameters for textiles dyed with natural dyes; and test of compatibility for application of binary mixture of natural dyes. The chemical modification of textile substrate for improving dyeability, attempts for improvement in overall colour fastness properties and survey of some traditional processes of natural dyeing. Cationic dye fixing agent, Colour fastness, Dye characterization, Natural dye, UV absorber. Characterization and Chemical/ Biochemical Analysis of Natural Dyes, Macro- and Micro-chemical Analysis. The chemistry, chemical composition and chemical based classification of natural dyes having anthraquinone (madder), alpha naphthoquinones (henna), flavones (weld), indigoids (indigo and tyrian purple), carotenoids (annatto, saffron), etc. which give a basic understanding of chemical nature of such colorants. Mordanting is the treatment of textile fabric with metallic salts or other complex forming agents which bind the natural mordantable dyes onto the textile fibers. Mordanting can be achieved by either pre-mordanting, simultaneously mordanting and post-mordanting. Different types and selective mordants or their combination can be applied on the textile fabrics to obtain varying colour/ shade, to increase the dye uptake and to improve the colour fastness behavior of any natural dye.
