Enhanced colour, hydrophobicity, UV radiation absorption and antistatic properties of wool fabric multi-functionalised with silver nanoparticles

In this study, multifunctional wool fabrics were produced by treating them with silver (Ag) nanoparticles in a single-stage treatment using trisodium citrate (TSC) as a reducing and capping agent. The effects of treatment parameters, such as Ag+ concentration, pH, temperature and time on the colour strength, antibacterial and antistatic properties, and UV radiation absorption by the treated fabric were carried out. It was found that the wool fabric treated with Ag nanoparticles formed by using Ag+ concentration of less than 1.11% on the weight of wool fibres produced very pale shade. The colour strength and UV radiation absorption capacity of the treated wool fibres increased with an increase in the concentration of Ag+, and Ag+ to citrate anion ratio, and also with a decrease in the treatment pH. The treatment temperature had a great effect on the colour strength of the treated fabrics and the size of Ag nanoparticles. The colour strength increased from 1.59 for the fabric treated at 55 °C to 7.74 for the fabric treated at 95 °C. The surface resistance of the treated wool fibres decreased with an increase in the concentration of Ag+, while the colour fastness to washing decreased for the fabric treated at a higher pH. The treated fibres showed excellent antibacterial activity, UV radiation absorption capacity, and also very good antistatic properties along with an excellent colourfastness to washing. Moreover, the developed treatment is highly durable to washing as after 20 washes the treated fibres lost their colour and antibacterial activity only marginally

Enhanced antimicrobial activity and reduced water absorption of chitosan films graft copolymerized with poly(acryloyloxy)ethyltrimethylammonium chloride

Chitosan shows selective antimicrobial activity as a bioactive polymer. In this work, a quaternary ammonium derivative of chitosan was synthesized by graft-copolymerization of chitosan with poly[2-(acryloyloxy)ethyltrimethylammonium chloride] or pATC by the redox polymerization method to enhance chitosan's antimicrobial activity. The structural characterizations of the quaternized chitosan were confirmed by Fourier transform infrared spectroscopy, and also by 1H and 13C nuclear magnetic resonance spectroscopy. The produced chitosan was converted into films by solution casting. The physicomechanical properties of the modified chitosan were compared with the unmodified chitosan. Thermal stability of the films was characterized by thermogravimetric analysis. The pATC grafted chitosan films showed lower thermal stability, water absorption, swelling ratio, and tensile strength compared to the unmodified chitosan film. Antimicrobial activity of the quaternized chitosan was tested against three kinds of bacteria (Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and two fungi (Aspergillus brasiliensis and Aspergillus fumigatus). The unmodified chitosan showed good antibacterial activity but no resistance against any fungus. However, the pATC grafted chitosan showed enhanced antibacterial activity against all bacteria investigated. The fungicidal test shows that the pATC-grafted-chitosan showed higher activity against the tested fungi (Aspergillus fumigatus and Aspergillus brasiliensis) compared to the unmodified chitosan, especially against Aspergillus fumigatus

Antibacterial and Antifungal Thioglycolic Acid-Capped Silver Nanoparticles and Their Application on Wool Fabric as a Durable Antimicrobial Treatment

Currently used silver nanoparticle-based antimicrobial treatments are effective against bacteria and certain fungi but they have limited durability to washing. In this work, the surface of silver nanoparticles was modified with thioglycolic acid (TGA) to further enhance their antimicrobial activities and also to enable their binding to the surface of wool fibre. Silver nanoparticles were characterised by FTIR, UV-vis spectroscopy and TEM. The TGA-capped silver nanoparticles were covalently bonded to wool fibre surface by using 1-ethyl-3-[3-dimethylaminopropyl]-carbodiimide hydrochloride in combination with N-hydroxysuccinimide to provide enhanced durability to multiple washings, which is an issue for the nanosilver-based treatments used in wool textiles. The antimicrobial activities of this treated wool fabric were compared with the wool fabric treated with trisodium citrate (TSC)-capped silver nanoparticles (bonded by a silicone resin). The TGA-capped silver nanoparticle-treated wool fabric not only showed superhydrophilicity and excellent durability to washing but also excellent antibacterial activity along with moderate to excellent antifungal activity. The wool fabric treated with TSC-capped silver nanoparticles showed strong hydrophobicity and antibacterial activity but no antifungal activity. This work demonstrates that silver nanoparticles can be made antifungal by the capping with TGA and also the durability of the treatment to washing can be considerably enhanced

Valorization of Sulfonated Kraft Lignin as a Natural Dye for the Sustainable Dyeing of Wool Fabrics: Effect of Peroxide Oxidation

Lignin is an abundant and complex biopolymer with inherent color but has only a few applications. It has the potential to replace synthetic acid dyes for the coloration of wool fibers in brown shades, as traditional dyeing with acid dyes produces toxic effluent needing costly treatment. In this work, the valorization of sulfonated lignin was explored by using it as a natural dye for the coloration of wool fabrics alone and with hydrogen peroxide (H2O2). The dyed fabrics were characterized by reflectance and diffuse reflectance spectroscopies to assess the color yield and ultraviolet (UV) protection performance, respectively. The dyed fabrics exhibited reasonably good color yield and satisfactory colorfastness to washing (Grade 3/4), which improved to Grade 4 by the oxidation treatment with H2O2. The scanning electron microscopy (SEM) images show that when fabrics are dyed alone with lignin, deposition of lignin particles is visible on the fiber surface, but with hydrogen peroxide, no deposition of lignin is visible on the fiber surface, and the color strength of the fabric became almost double. The UV light transmission through the fabric decreased from 6.73 and 13.23% at 311 and 365 nm to 2.19 and 5.23%, respectively. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra of the dyed fabrics showed increased absorption of lignin sulfonate by the fabric, suggesting depolymerization of lignin by H2O2 to smaller macromolecules easing absorption into the wool fiber. Lignin sulfonate could be a cheap and sustainable alternative to harmful synthetic dyes for producing brown shades on wool fabric

Enhanced thermal stability, hydrophobicity, UV radiation resistance, and antibacterial properties of wool fabric treated with p-aminobenzenesulphonic acid

Wool fibre is a popular fibre for the manufacture of apparel and floor coverings, but it does not have adequate thermal stability, antistatic, UV resistance, and antibacterial properties that are required for some applications, such as outerwear and hospital gowns. In this work, a wool fabric was treated with para-aminobenzenesulphonic acid (ABSA) by the oxidative polymerisation method and its effect on the thermal stability, UV radiation resistance, electrical conductivity and antibacterial properties of the treated fabric was systematically evaluated. It was found that the ABSA treatment had synergistic effects on the various functional properties of the treated fabric. The ABSA treatment not only made the fabric antibacterial but also enhanced its UV radiation absorption capability, surface hydrophobicity, electro-conductivity, tensile strength, and thermal stability. The maximum degradation temperature of the wool fibre increased from 339.5 °C to 349.6 °C and the UV-B transmission through the fabric at 290 nm reduced to 1.5%. The surface hydrophobicity of the treated fabric samples also improved as the surface contact angle of the fabric increased from 119.5° for the untreated to 131.7° for the fabric treated with 4% ABSA. The surface electrical resistance decreased from 1200 × 109 to 484 × 109 Ohm cm−1, and the treated fabric also showed excellent antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae. The developed treatment could be used in the textile industry as an energy-efficient process for the multi-functionalisation of wool and other polyamide fibres

Sustainable dyeing of ramie fiber with ternary reactive dye mixtures in liquid ammonia

Liquid ammonia (LA) dyeing is a zero-effluent and sustainable dyeing technology investigated for textiles. In the present work, three bi-functional reactive dyes, Reactive Red 195 (R195), Reactive Yellow 145 (Y145), and Reactive Blue 194 (B194), were used to dye ramie fiber in liquid ammonia, and the dye exhaustion (%) and fixation (%) were compared with ramie fibers dyed with the same dyes in an aqueous dyeing method. Dyeing with a single reactive dye, a binary dye mixture, and a ternary dye mixture in liquid ammonia showed that all the dyes are highly compatible as they showed similar uptake. The total dye exhaustion percentage of dyeing with the ternary dye mixture was 22.6%. After dyeing, a cationic fixing agent (CFA)/decamethylcyclopentasiloxane (D5) micro-emulsion was applied and the dye fixation rate was 96.7% accompanied by high colorfastness to washing (Grade 4–5) and produced uniform shades. Finally, a color triangle of dyed ramie fibers was prepared to exhibit many colorful shades. This work demonstrates the viability of dyeing of textile fibers in liquid ammonia

Valorisation of sulphonated lignin as a dye for the sustainable colouration of wool fabric using sustainable mordanting agents: Enhanced colour yield, colourfastness, and functional properties

Biodegradable sulphonated lignin (SL) can be used as a natural dye for the sustainable colouration of wool fabric. for producing brown shades on wool fabric, but the colourfastness to washing is only moderate, and the colour strength is also weak. In this work, wool fabrics were dyed with various concentrations of water-soluble sulphonated lignin using several sustainable mordanting agents to improve the colour yield and also the colourfastness to washing along with introducing new functional properties, such as UV protection capabilities. The colour yield of wool fabric dyed with lignin sulphonate using various mordanting agents was measured by reflectance spectroscopy. The Al and Ca mordants produced brown colour but the Cu and Fe mordants produced olive and grayish-brown colours respectively. The dyed fabrics exhibited high colour yield and enhanced colourfastness to washing. The dyed fabrics exhibited high colour yield, which increased with an increase in the lignin concentration and also showed improvement in colourfastness to washing by a grade. The highest colour strength was produced by wool fabric treated with 5% on the weight of fibre lignin sulphonate using Cu mordant at 35% on the weight of applied SL (ows). The Al and Ca mordants produced brown colour but the Cu and Fe mordants produced dark olive and dark greyish brown colours respectively. The colourfastness increased to Grade 4 for all the mordanting agents studied in this work. The Cu mordant provided the highest colour strength (4.21) for the fabric dyed with 5% (on the weight of fibre) lignin sulphonate at Cu mordant concentration of 25% on the weight of lignin sulphonate (ows) and increased the colourfastness to washing to Grade 4/5 for the fabric dyed with 5% lignin using Cu mordant concentration of 35% (ows). The results suggest that The developed method can be used for the sustainable dyeing of wool fabrics in the textile industry with high colour yield and colourfastness to washing for producing verities of colours

Energy-efficient dyeing of wool fabrics with sulfonic acid derivatives of aniline by oxidation polymerization

Traditionally, wool fibers are dyed with acid dyes at the boil, which is energy-intensive process, and increases the cost of dyeing. The development of alternative energy-efficient dyeing processes is quite attractive to the textile industry to make textile dyeing sustainable. In this work, the feasibility of low-temperature dyeing of wool fabric with several aniline sulfonic acid (ASA) derivatives by oxidative polymerization method was investigated. The effect of dyebath conditions, such as monomer concentration, monomer to oxidant ratio, pH, temperature, and time on the shade produced and color strength was systematically studied. The treatment with various ASAs produced various yellowish-brown color shades with tonal change. The treatment conditions had a great effect on color strength and colorfastness to washing. The optimum treatment conditions were found to be pH 3, 30 °C, and 60 min. The excellent colorfastness to washing exhibited by the ASA-treated fabrics (colorfastness grades from 4 to 4–5) showed that the developed method could be used for the coloration of wool and other polyamide fibers

Enhanced insect-resistance, UV protection, and antibacterial and antistatic properties exhibited by wool fabric treated with polyphenols extracted from mango seed kernel and feijoa peel

The synthetic dyes, antimicrobial and insect-resistant agents, UV radiation absorbents, and antistatic agents that are used to introduce multifunctional properties to textiles are not only toxic to the environment but also require multi-step treatments to achieve them. Toxic antimicrobials are responsible for the growth of drug-resistant bacteria. Nature-derived polyphenols, such as tannin, could be a viable green alternative. In this work, wool fabrics were treated with a commercial tannic acid (PP-1), and also with gallotannin-rich polyphenols extracted from feijoa fruit peel (PP-2) and mango seed kernel (PP-3) to introduce multifunctional properties, i.e. to make the fabric antistatic, insect-resistant, hydrophilic, and able to absorb harmful UV radiation. The effect of the treatment on the colour, colour intensity, surface resistivity, UV radiation absorption, antibacterial activity, and insect-repellence was systematically evaluated. It was found that PP-3-treated fabric exhibited excellent surface hydrophilicity, antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and insect-resistant activity against the larvae of Tineola bisselliella. PP-3 treatment also provided comparable UV protection and antioxidant activity but was marginally inferior to the UV protection and antioxidant activity exhibited by the PP-1-treated fabric. The commercial tannic acid treated fabric provided the best antistatic properties but the lowest surface hydrophilicity. The developed treatment could provide a green and sustainable alternative to hazardous UV absorbing, antibacterial and insect-resistant agents used in the textile industry