Thermodynamics, Kinetics, and Multifunctional Finishing of Textile Materials with Colorants Extracted from Natural Renewable Sources

Because of a continued ban on some toxic synthetic dyes, textile and polymer scientists are presently in a constant search for alternative greener agents that can reduce pollution in textiles industries. Natural dyeing is one such promising technology that has the potential to clean up environmental pollution arising due to excessive use of toxic synthetic dyes and chemical auxiliaries. Dyeing compounds extracted from natural materials have produced sober and elegant shades on different types of fabrics over the past few years and are currently investigated as novel functional agents in the production of highly active textile surfaces having deodorizing, antioxidant, antimicrobial, antifeedant, and UV protection properties. The present perspective is intended to outline the recent research in functional finishing of different textile substrates with colorants and functional agents exploited from natural renewable sources. To the best of our knowledge, this perspective discusses for the first time thermodynamic and kinetic studies of natural colorants in order to elucidate dyeing mechanisms or understand dye–fiber interactions arising during the dyeing process. Finally, it also highlights the limitations of this technology and provides the scope for further investigations to corroborate existing gaps in order to make natural textile dyeing less vulnerable and widely acceptable in modern dye houses.