In Situ Synthesis of a Double-Layer Chitosan Coating on Cotton Fabric to Improve the Color Fastness of Sodium Copper Chlorophyllin

Bio-mordants: a review

Due to the increasing pressure on environmentally friendly approaches and sustainable production processes, the textile dyeing industry has focused on natural colorants. Thus, the use of bio-mordants, which are biological materials, has become widespread as an alternative to metal salts, most of which are non-ecological, used in the application processes of natural colorants. In natural dyeing, dyers want to use mordant substances in the dyeing processes in order to both expand the color spectrum and improve the fastness properties. Conventional metal salts used in natural dyeing are made up of metallic ions, which, when released into the environment as wastewater effluent at the end of the dyeing process, cause major damage to the ecosystem. Many researchers have thought about using mordants derived from natural sources to address the environmental problem. This article is a review of the investigation of natural mordants used instead of metallic mordants in the process of coloring various textile materials with natural dyestuff sources. It has been determined that many substances, most of them herbal materials, are used as mordants. In this review, mordants, except for conventional metal salts, are examined under three main groups for a better understanding. These groups are as follows: (i) natural or bio-mordants, (ii) oil mordants, and (iii) new-generation and non-vegetable-based mordants. Here, researchers will find an overview of the most recent developments in green mordants as well as application techniques for a variety of mordants.

Dyeing Improvement and Stability of Antibacterial Properties in Chitosan-Modified Cotton and Polyamide 6,6 Fabrics

Cotton and polyamide 6,6 fabrics coated with chitosan, a natural biopolymer, have been tested against two different bacteria strains: Staphylococcus aureus as Gram-positive bacterium and Escherichia coli as Gram-negative bacterium. Using the ASTM standard method (Standard Test Method for Determining the Antimicrobial Activity of Antimicrobial Agents Under Dynamic Contact Conditions) for antibacterial testing, the treated fabrics is contacted for 1 h with the bacterial inoculum, the present study aims to investigate the possibility to reach interesting results considering shorter contact times. Moreover, the antibacterial activity of chitosan-treated fibers dyed with a natural dye, Carmine Red, was evaluated since chitosan has an interesting property that favors the attachment of the dye to the fiber (cross-linking ability). Finally, fabric samples were tested after washing cycles to verify the resistance of the dye and if the antibacterial property was maintained.

Citric Acid Cross-Linking of Chitosan Encapsulated Spearmint Oil for Antibacterial Cellulosic Fabric

This study presents the encapsulation of spearmint oil (SMO) in chitosan microstructures prepared through the emulsion formation method. The SMO although is medicinally significant yet finds limited applications in medical and functional textiles because of its less stability and high volatility under ambient conditions. Nevertheless, its encapsulation in chitosan may enhance its stability and applicability for the said purpose. The SMO encapsulating chitosan microstructures were characterized using different analytical techniques and applied on cotton fabric through a green crosslinking of citric acid. The treated fabric revealed successful adhesion of microcapsules onto its surface confirmed via SEM and FTIR analyses. There observed a slight decrease in tensile strength of treated fabric; that, however, improved crease recovery behavior, and good antibacterial activity in response to broad-spectrum bacterial strains by reducing their 99% population; whereas, the stiffness of such fabric exhibited somehow increasing trend. Hence value-added multifunctional textiles produced, herein, may provide both surface and antibacterial activity for potential medical and healthcare applications without compromising their comfort properties.