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Purpose Sulphur dyes are the most highly consumed colourants for cellulosic substrates owing to their reasonable cost and acceptable fastness. However, the use of noxious conventional reducing agent, sodium sulphide and impaired wash fastness against oxidative bleaching is gradually decreasing the market of these dyes. As the need for “Green” goods and services is raising public awareness, this paper aims to use a glucose-based biodegradable reducing agent in place of sodium sulphide to dye cotton fabrics with a range of commercial sulphur dyes. The study also proposes an aftertreatment method to improve the fastness properties of the dyeing. Design/methodology/approach The paper investigated the impact of a newly developed aftertreatment method on the fastness properties of dyeing. This involved the sequential application of a cationic fixing agent (Tinofix ECO) and tannin (Bayprotect CL) on the coloured fabrics and subsequent evaluation of colour strength, washing, light and rubbing fastness. Findings The effect of aftertreating the dyed cotton was found to significantly improve the light and wet rub fastness. The surface morphology of the dyeing remained unaffected as depicted by the absence of any finish residues. Research limitations/implications The protective effect of the cation–tannin aftertreatments was examined with a view to providing the necessary commercial performance; however, it was established that the dry rub fastness was either reduced or remained unaffected and the wash fastness to International Organization for Standardization 105 C09 was also marginal. Originality/value This finishing technique is novel and can be found useful for manufacturing sulphur-dyed products with the improved light and wet rub fastness.

The interest in pH-sensitive textile sensors is growing in the global market. Due to their low-cost production, mechanical stability, flexibility, air-permeability, washability, and reusability, they are more suitable than electronic sensor systems. The research tailored the pH-sensitive textile by applying the pH indicator methyl orange to the cotton fabric during conventional dyeing. Adsorption of methyl orange dye to cotton fabric is hindered due to electrostatic repulsive forces between dye anions and negatively charged cotton fibre. To overcome this problem, chemical modification of cotton fabric using a commercial product was performed. The pH sensitivity of the dyed fabric was spectrophotometrically evaluated. In addition, the colour fastness of dyed cotton fabric to washing, light, hot pressing and rubbing was investigated according to valid SIST EN ISO standards. The research results show that the pH-responsive cotton fabric was successfully developed. The chemical modification of cotton fabric is crucial for the increased adsorption of methyl orange dye. The halochromic effect was not only perceived spectrophotometrically but also with the naked eye. The developed halochromic cotton fabric showed poor colour fastness to light and good colour fastness to hot pressing and rubbing, while no significant improvement in colour fastness to washing was observed, even though the fabric was after-treated with a cationic fixing agent. Higher adsorption of the methyl orange dye to the cotton fabric during the dyeing process leads to less wastewater pollution after dyeing with unfixed dye and, thus, a reduction in wastewater treatment costs.

The current study investigates the chemical modification of cotton fiber using a commercially available cationic agent (Albafix Eco ® ) through a simple method to enhance the anionic (reactive) dye exhaustion without the need for auxiliaries. In this study, 100% cotton knit fabric was treated with various concentrations of Albafix Eco ® , ranging from 0.1% to 1%. Subsequently, the modified cotton fabrics were dyed with three reactive dyes: Novacron Navy EC-R, Novacron Ruby S-3R, and Novacron Yellow S-3B, without electrolytes. The FT-IR studies and zeta potential analysis confirmed the successful incorporation of cationic agents into the cellulose outer surface. The key indication was the abrupt increase of surface zeta potential from − 13.3 (pristine cotton fiber) to 17.3 (modified cotton fiber) with uniform coverage of the fiber surface. The highest dye exhaustion (more than 95%) was achieved with fibers modified using a 0.5% Albafix Eco concentration. The highest dye uptake was observed for the modified fabrics when the dyeing bath conditions were neutral pH (pH 7), temperature 60℃, and run for 60 min (i.e., Novacron Ruby 90%, Novacron Navy 93%, and Novacron Yellow 98%). The overall colorfastness of the dyed fabric was good to excellent. This study could be an example of a cost-effective way of dyeing cotton with reactive dye that has minimal negative impact on the environment and the highest dyestuff utilization. Graphical Abstract Highlights Modification of cotton fabric with Albafix Eco® to boost dye absorption. Optimizing the concentration of Albafix Eco® for the best dye exhaustion in cotton treatment. Finding optimal dyeing conditions for maximum dyestuff use and efficiency. Assessing color fastness to ensure an eco-friendly cotton dyeing process.

Previous studies have established that sequential cation-tannin after-treatment on sulfur dyed cotton fabric can improve the oxidative washing resistance against perborate-based laundering regimes. In this investigation, C.I. Sulfur Black 1 dyed cotton fabric was after-treated with a cationic fixing agent (Tinofix ECO) and tannin-based product (Bayprotect CL) and laundered with ISO 105 C09 washing protocol. The dyeings were evaluated for color strength and wash fastness. The surface functionalities and elemental composition of the dyeings were analyzed by using the surface sensitive X-ray photoelectron spectroscopy (XPS) to compare visual changes with surface chemical changes. After-treated and laundered dyeings exhibited higher content of surface sulfur and lower surface oxidation as compared to the untreated counterparts. The S (2p) spectra of after-treated and laundered samples demonstrated reduced over oxidized (S6+) species at 168 eV. The effect of laundering and modification to the surface sulfur dye was related to K/S and % color loss analysis.

The issue encountered by the textile industry is that the colours are fading off, particularly in denim fabric, by constant washing, so fixing agent is needed to enhance the colour fastness of the denim fabric. Polyurethane is one of the promising types of nonformaldehyde dye fixing agents. It has good film covering properties and allows air permeability. In this study, cationic polyurethane dispersions (CPU) were syntheses and applied as fixing agent for sulphur dye denim fabric. Different formulation of CPU were synthesized using isophorone diisocyanate, different molecular weight of polyols, and tertiary amine. Formulated CPU were then analysed using FTIR, zeta potential analyser and viscometer. Zeta potential obtained was in the range of +8.1 mV to +41.7 mV indicates that some of the CPU particles tend to agglomerate and some are stable. After fixing treatment, colour fastness to crocking of the treated fabric has improved. Surface morphology changes were determined by SEM and it shows that smooth finishing fibre surface was obtained in treated black denim fabric.

The nature and wash durability of the cationic fixing agent Matexil FC-ER applied to Tencel fabric, at pH 6 and 11, respectively, was investigated by X-ray Photoelectron Spectroscopy (XPS). The N(1s) XPS spectrum of the Matexil FC-ER film indicated that the concentration of uncharged and quaternary nitrogen species was in the ratio of 5:1. For both pH 6 and pH 11 applications, the surface concentration of the cationic fixative appeared to be independent of pH and the relative proportion of cationic nitrogen relative to the original film, increased at the fibre surface. The ISO 105 CO6/C2S wash test removes the uncharged nitrogen from the fibre surface leaving only the cationic nitrogen species. The surface Matexil FC-ER was durable to washing, while in contrast a direct dye applied to the Tencel fibre was not. Combination with the cationic fixing agent increased the fastness of the dye at the Tencel fibre surface.

In this study, a two-stage aftertreatment using a cationic fixing agent and tannin was found to improve the wash fastness of sulphur black 1 dyed cotton fabric to ISO 1O5 CO9 washing. The light and rub fastness of sulphur black 1 dyed cotton fabric remained the same for untreated and aftertreated dyeings. The improved wash fastness was due to the formation of large molecular size, low solubility, cation-tannin complexes within the periphery of the dyed and aftertreated fabric.

In the indeterminate nodules of a model legume Medicago truncatula, ∼700 nodule-specific cysteine-rich (NCR) peptides with conserved cysteine signature are expressed. NCR peptides are highly diverse in sequence, and some of these cationic peptides exhibit antimicrobial activity in vitro and in vivo. However, there is a lack of knowledge regarding their structural architecture, antifungal activity, and modes of action against plant fungal pathogens. Here, the three-dimensional NMR structure of the 36-amino acid NCR044 peptide was solved. This unique structure was largely disordered and highly dynamic with one four-residue α-helix and one three-residue antiparallel β-sheet stabilized by two disulfide bonds. NCR044 peptide also exhibited potent fungicidal activity against multiple plant fungal pathogens, including Botrytis cinerea and three Fusarium spp. It inhibited germination in quiescent spores of B. cinerea. In germlings, it breached the fungal plasma membrane and induced reactive oxygen species. It bound to multiple bioactive phosphoinositides in vitro. Time-lapse confocal and superresolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, subsequent accumulation in the cytoplasm, and elevated levels in nucleoli of germlings. Spray-applied NCR044 significantly reduced gray mold disease symptoms caused by the fungal pathogen B. cinerea in tomato and tobacco plants, and postharvest products. Our work illustrates the antifungal activity of a structurally unique NCR peptide against plant fungal pathogens and paves the way for future development of this class of peptides as a spray-on fungistat/fungicide.