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To develop a method based on urea/microwave treatment for improving the dyeability of the flax fibre.

The treatment was carried out under a variety of conditions in terms of the power of the microwave, the time of microwave treatment and the use of urea in the treatment solution. The physical chemical properties of the treated flax fibres were characterised using a variety of techniques including scanning electron microscopy (SEM), X‐ray diffractometry, spectrophotometric measurement and tensile measurement.

It was found that the treated flax fibres had significantly improved dyeability. The causes to the improvement of the dyeability of the flax fibre were found to be the increased absorption of dye on the fibre and the increased reaction probability between the dye and the fibre. The procedure for optimum modification appeared to be soaking the flax fabrics in 10 per cent urea solution; treating the fabrics with microwave at 350 W for 2.5 minutes; and treating the fabrics with microwave at 700 W for one minute.

The treatment method developed addressed a problem of great concern in textile coloration, i.e. poor dyeability of flax fibre. The method developed provided a practical and effective solution to such a problem.

The method of treatment of flax fibre, involving soaking in urea and baking in microwave, for the improvement of dyeability was novel. The method could be adapted for use in industrial scale flax dyeing with satisfactory levels of exhaustion and fixation.

To evaluate the efficiency of modifying flax fibre using copper ammonia solution for improved dyeability and to optimise the conditions of such a modification.

Treatments of flax fibre using copper ammonia solution were carried out under various conditions, i.e. the compositions of the solution and the length of time for treatment. The dyeability, the dyeing colour depth, the tensile strength and the structure of the untreated and treated flax fibres were characterised.

The modification of flax fabric using copper ammonia solution could improve the dyeability and the dyeing colour depth of the flax fabric. The treatment appeared to reduce the crystallinity and the orientation index of the flax fibre, which was the main cause to the improved dyeability and dyeing colour depth of the flax fabric. The optimum conditions for the treatment were as follows: concentration of Cu²⁺ at 20 g/L, Cu²⁺/NH₃ ratio at 12 : 1 and time of treatment at 6 min.

Whilst effective in improving the dyeability of the flax fibre, the treatment led to a reduction in the tensile strength of the treated flax fabric.

The method developed provided a simple and practical solution to improve the dyeability of flax fibre.

The method for treatment of flax fibre was novel and could be used for industrial production process.

The purpose of this paper is to improve the dyeability of flax fibre by modification via urea treatment and to explore the mechanism of such improvement.

The modification to the flax fibre was carried out with different concentrations of urea solution, then the optimum condition for the dyeability improvement was investigated by the measurement of the dyeing colour depth. The chemical properties of the raw and the treated flax fibres were characterised using a variety of techniques including Fourier transform‐infrared spectroscopy analysis and X‐ray photoelectron spectroscopy analysis.

It was found that the dyeability of flax fibre had been significantly improved via urea treatment. The mechanism of the improvement of the dyeability of the flax fibre was found to be due to the amino groups (NH₂) introduced to the flax fibres during urea treatment, which increased the activity of the reaction between the dye and the fibre compared to hydroxyl groups of raw flax fibre.

The treatment method developed provided a practical and effective solution to poor dyeability of flax fibre.

The method could be adapted for use in industrial scale flax dyeing with satisfactory levels of exhaustion and fixation.

The dyeing of cellulosic and proteinous fibers with natural and synthetic colorants usually needs large amounts of metal salts to promote the dyeing procedure. To get rid of the necessity to use metal salts, plasma treatment and subsequent attachment of chitosan biopolymer were considered as green processes for surface functionalization of wool and cotton. The purpose of this paper is to investigate the effect of oxygen plasma treatment and attachment of chitosan on the dyeability of wool and cotton fabrics using walnut and weld as model natural dyes, as well as C.I. reactive blue 50 and C.I. acid blue 92 as model synthetic dyes.

Wool and cotton fabrics were modified with oxygen plasma and coated with chitosan solution. The un-modified and modified samples were dyed with the above-mentioned dyes under constant conditions. The color strength, color coordinates and fastness properties of the dyed samples were determined and compared.

The results showed that oxygen plasma treatment could improve the dyeability and fastness properties of wool and cotton fibers when dyed with all of the above-mentioned dyes. Attachment of chitosan to the plasma-treated samples significantly improved the dyeability of wool and cotton fibers with walnut, acid and reactive dyes. The fastness properties of the dyed samples were enhanced by plasma treatment and chitosan coating.

This study uses plasma treatment as an environmentally friendly pre-treatment for attachment of chitosan on wool and cotton. This process improved the dyeing properties of both fibers. The use of metal salts in not needed for dyeing of wool and cotton according to the investigated process.

The purpose of this study is to check the effectivity of plasma in the natural dyeing of polyester fabric using four natural dyes – Turkey red, Lac, Turmeric and Catechu using plasma and alum mordant. The surface modification on the polyester fabric by plasma along with the use of benign mordant alum is studied. The enhancement of dyeability in polyester fabric with natural dyes is the main focus. Due to surface modification, the wettability increases, which leads to better dye uptake. Better dye uptake and better dye adherence are the main objectives.

Plasma-mediated natural dyeing is the main design of this research work. The effect of plasma treatment on surface modification of synthetic fabric polyester and its subsequent effects on their dyeing with different natural dyes, namely, Turkey red, Lac, Turmeric and Catechu are studied. The dyeability was further enhanced by the use of alum as mordant. The main focus is on the betterment of natural dyeing of polyester fabric using sustainable natural dyes resources for dyeing and to reduce wastewater contamination from the usage of toxic additive chemicals for cleaner production.

Plasma-mediated and alum-mordanted dyeing method facilitated very good dyeability of all the four natural dyes, namely, Turkey red, Lac, Turmeric and Catechu. Color strength (K/S) values and fastness properties of plasma-treated samples were far better than untreated samples. The synergistic effect of plasma and alum mordanting has made natural dyeing of polyester very easy with very good fastness results. Natural dyeing of polyester after 2 min of plasma treatment showed excellent and desirable results. The process is also easy to be adapted by industries.

As polyester is hydrophobic, natural dyeing of polyester fabric is not very easy, but with plasma-mediated natural dyeing, it becomes a very facile dyeing method; thus, there are no limitations. Use of plasma has reduced the need for any chemical additives which are usually added during the dyeing process.

This process of natural dyeing of polyester fabric can be scaled up to industrial dyeing with natural dyes. Plasma pretreatment of the fabric followed by premordanting with alum has facilitated the natural dyeing well.

Use of plasma in place of chemical modifiers can be a green and environmentally friendly approach for sustainable coloration of polyester fabric, providing a clean wet processing for textiles dyeing.

The synergistic effect of plasma-mediated and alum-mordanted natural dyeing of polyester has not been attempted by any researcher. To the best of the authors’ knowledge, this is for the first time that pretreatment with atmospheric plasma followed by alum mordanting of polyester fabric has shown very good dye uptake and fastness properties as the dye molecules could penetrate well after 2 min of the plasma treatment.

The aim of this research is to investigate the influence of low molecular weight chitosan (LWCS) on the dyeability of cotton fabrics. Various concentrations of hydrogen peroxide were used to degrade chitosan to LWCS, which was used to pretreat cotton fabrics under different conditions in order to determine its influence on subsequent acid dyeing of the fabrics. The results showed that the molecular weight of LWCS decreased with increasing concentration of hydrogen peroxide. Additionally, LWCS pretreatment of cotton fabric is beneficial for acid dyeing. The K/S values for fabric dyeing increased with a decrease in LWCS molecular weight and the concomitant increase in concentration; a concentration of 4% LWCS yielded the best result. The anti-bacterial properties of fabrics pretreated with LWCS were better than those pretreated with chitosan. The dye and anti-bacterial fastness after 20 washes were best for fabrics pretreated with LWCS.

In the present study, cotton fabrics are dyed with extracts obtained from the rinds of the pomegranate fruit, Punica (P.) granatum. The fabrics are then assessed for antimicrobial, dyeability and fastness properties. The colour strength (K/S) of the dyed fabric is assessed through a dyeability test. The finished fabrics are qualitatively assessed for antibacterial activity by the disc diffusion and parallel streak methods (AATCC 147) and quantitatively by the percentage reduction test (AATCC 100) against the test organisms, Escherichia coli and Staphylococcus aureus. The fabrics are also assessed for fastness properties, such as wash, light and rubbing fastness per AATCC standards. The fabrics are then finally subjected to wash durability tests. The dyeability results show that the fabrics dyed with P. granatum rind extracts have a high K/S value when compared with the untreated control fabric. The natural extract dyed fabric has prominent antimicrobial activity which is evidenced by a clear zone of bacterial inhibition in qualitative tests and bacterial reduction in quantitative tests whereas the control fabrics have no antibacterial activity. Wash durability testing shows that the antimicrobial activity of the fabrics is durable up to 10 wash cycles.

Acrylic fabrics are treated with aluminum sulphate, copper sulphate, tannic acid and isophthalic-5-sodiumsulphonic acid in different concentrations and various temperatures in presence and absence of plasticizer agents, such as dimethylformamide (DMF) or dimethylsulphoxide (DMSO). The treatment is carried out by two techniques (padding and exhaustion). Then, pretreated acrylic fabrics are dyed with cationic and acid dyes for various times. The effects of the treatments on the mechanical and physical properties of the treated acrylic fabrics such as moisture regain, roughness, tensile strength, elongation and bending stiffness are thoroughly investigated. Infrared spectroscopic analysis has been used to suggest changes in the treated acrylic fabrics. The dyeability of the treated fabrics by both cationic and acid dyestuffs is studied. The effects of the treatments with metal salts and acids on fastness properties of dyed acrylic fabrics are estimated. The pretreatment improves the dyeability of acrylic fabrics modified with both cationic and acid dyestuffs and also their fastness properties.

Equisetum arvense L. (Equisetum) is a weed that is very difficult to remove because of its deep roots. The purpose of this paper is to examine the dyeability and antioxidant activity of Equisetum extracted from hot water.

Dry Equisetum was extracted at 100°C for 2 h, and its dyeability according to time, temperature and repetition cycle, and the mordant effect by skim milk powder were confirmed. The color change according to the K/S, fastness to rubbing, light, sweat and washing, UV protection rate and antioxidant activity were evaluated.

UV‒Vis spectroscopy showed that the Equisetum extract contained a flavonoid compound. The addition of Equisetum to artificial silk produced the greatest color difference when dyed at 60°C for 1 h, and the K/S value increased slightly after the pre-mordant treatment. In the fastness test, light and washing had no significant effect, but the fastness to rubbing was very good at Grades 4 and 5, and there was also a considerable improvement in the UV protection rate. The antioxidant activity of the extract was confirmed by an analysis of the radical scavenging ability through the DPPH (1,1-diphenyl 2-picryl-hydrazyl) and ABTS ([2,2’- azino-bis (3-ethylbenzothialzoline-6-sulfonic acid) diammonium salt]) tests.

These results revealed a new natural antioxidant-containing dyestuff, weed grass, which is easy to obtain, easy to use as a dyeing material and has excellent antioxidant activity in an extracted dye solution and dyeing fabric.

To explore the use of power ultrasound as an environmentally friendly heating technology for the pre‐treatment of linen fibres with sodium perborate as the halogen free oxidising agent and to study the impact of this process on its dyeability with reactive dyes.

Exploiting power ultrasound in the wet processes of linen fibres was made in two steps, i.e. ultrasonic pre‐treatment with sodium perborate followed by ultrasonic dyeing with reactive dyes. Therefore, comparative studies between conventional and ultrasonic techniques as well as the different factors that may affect these processes were investigated. The effect of the pre‐treatment on fibre fine structure using X‐ray diffraction technique was also investigated.

The results of the increase of whiteness index indicate that ultrasonic pre‐treatment was better at all studied treatment times and at low temperature. X‐ray diffraction studies on blank, ultrasonically and conventionally pre‐treated linen fibres have shown 70.41, 67.51 and 64.90 per cent crystallinity, respectively. The dyeing of the pre‐treated fibres with Reactive Red 24 was simultaneously carried out under both ultrasonic and conventional heating conditions to study the effect of dye concentrations at different dyeing temperatures. The colour strength values obtained for the dyed samples using ultrasonic at 50°C were slightly higher than those obtained using conventional heating at 80°C. Ultrasonic enhancement in the pre‐treatment and dyeing in terms of the percent increase of colour strength of the dyed fabric was estimated to be 157.94 per cent higher than that of conventional heating method. The results of wet fastness properties of the dyed fibres using ultrasonic revealed improvement relative to those obtained using conventional heating method.

The improved wet processes of linen fibres suggest further investigation to exploit power ultrasound in the wet processes of cellulosic fibres at low temperature using different classes of halogen free bleaching agents and dyeing with different classes of heat‐requiring reactive dyes. Also, this work may inspire the synthesis of new generation of heat‐requiring reactive dyes.

The work presented has significant potential industrial application for cleaner production in textile industries.

The present study of linen pre‐treatment with non‐toxic total chlorine free oxidising agent and its dyeability with reactive dyes using power ultrasound is novel and could be used in the wet processes of linen fibres.