Optimized Dyeing Process for Enhancing the Functionalities of Spent Coffee Dyed Wool Fabrics Using a Facile Extraction Process

Extracted dyes' stability as obtained from spent coffee grounds on silk fabrics using eco-friendly mordants

Spent coffee grounds (SCGs) are commonly known as a waste resource and a raw material useful for dyeing. SCG is a rich source of natural colorant from the class of flavonoids and anthocyanins. In this research, silk fiber dyeing with the dye which was extracted from SCGs with different metallic and natural mordants was done by applying pre-, meta-, and post-mordanting methods. Metal salts like tin chloride and copper sulfate as well as such natural materials as pinecone, tannic acid, and lemon peel were used to act as mordants. Color strength and color parameters of the dyed silk fabric samples were evaluated by applying a reflective spectrophotometer. Also, the evaluation of wash and light fastness was done based on ISO standards. The results indicated that in all methods, the metal samples had higher color strength when compared to the bio-mordant ones. Among the used methods and bio-mordants, the use of the pre-mordanting method and pinecone led to the highest amount of color strength. Also, the used bio-mordant could be a suitable substitute for metal mordants in terms of fastness parameters. Among the used methods and mordants, the post-mordanting method and pinecone mordant could provide the best washing and light fastness.

Study of Dyeing Process of Hemp/Cotton Fabrics by Using Natural Dyes Obtained from Rubia tinctorum L. and Calendula officialis

The objective of this work was to assess the possibility of dyeing a substrate composed of non-textile industrial hemp using natural dyes from common madder (Rubia Tinctorum L.) and calendula (Calendula Officialis) and tannin and alum as mordants. The substrate used for the dyeing had a 25/75 hemp/cotton composition. The hemp raw material is an agricultural by-product that was subjected to mechanical and chemical treatments in order to cottonize the fibers, blend them with cotton, and thus obtain first 40-tex open-end yarns and then a knitted fabric. The latter was subjected to different dyeing conditions by varying the dye, mordant, and method for its application, type of water, and rinsing after dyeing. Measurements of the difference (ΔE) and intensity (K/S) of color and fastness to washing and rubbing were carried out. The results showed that dyeing of a non-textile residual hemp substrate is possible, and that calendula is a good option for dyeing it with tap water, tannin-alum set in a meta-mordanting process, and rinsing after 24 h. In this way, a contribution has been made to the circular economy of the textile industry through the use of more sustainable sources and products.

Dyeing and Antibacterial Properties of Chemically Recycled PET Thermal-Bonded Nonwovens Dyed with Terminalia chebula Dye

Waste recycling is a necessary step for environmental conservation. To this end, polyester can be easily collected and recycled into end products. To promote the use of recycled polyester, it is important to expand its range of applications. We earlier reported the fabrication of recycled polyester thermal-bonded nonwovens. In this study, recycled nonwoven fabrics were dyed with Terminalia chebula dye without the use of additional mordants. To optimize the dyeing conditions, the dyeing time, dyeing temperature, and liquor concentration were varied, and the color strength, color changes, fastness properties, thermal stability, and morphology were evaluated. Further, the antibacterial activity of the dyed nonwoven was also estimated. T. chebula dyed the colored recycled rapid melting PET fiber (R-RM) nonwoven brown via the dyeing process, and the dyeablity was improved by increasing the dyeing temperature, time, and liquor concentration. The rubbing and sweat fastness properties were found to be excellent. T. chebula dye imparted efficient antibacterial properties to the R-RM nonwovens against Staphylococcus aureus and Klebsiella pneumonia. The results obtained in this study are expected to broaden the range of natural dyed recycled polyester fabric applications.

Surface Functionalization of Wool via Microbial-Transglutaminase as Bio-Mordant to Improve Dyeability with Madder in the Presence of Alum

Herein, the wool fabric was mordanted with alum, treated with microbial transglutaminase (m-TGase), and then dyed with madder. Different concentrations of alum and m-TGase were used to find out the optimum condition to achieve the best color after dyeing the wool fabrics with aqueous extract of madder. FT-IR spectroscopy and scanning electron microscopy (SEM) methods were applied to characterize the as-prepared samples. Contact angle measurements showed that the water uptake capability was increased in the case of the wool sample treated with alum and enzyme. Moreover, the samples were assessed for color strength (K/S) and color fastness. Our results showed that the optimal condition to get the highest color value was for the sample with 10% owf (of weight of fabric) alum and 5% owf m-TGase. Furthermore, it was found that there was a critical concentration for enzyme so that an increase in m-TGase amount would cause damage to the scales of fibers. The best condition of the dyeing process was discussed in this study, and also the proposed mechanism was presented. Indeed, treatment of wool with m-TGase led to a reduction in the amount of consumed alum, while investigations in color performances demonstrated the enhancement in color fastness, as well as color strength.