Novel feature of nano‐titanium dioxide on textiles: Antifelting and antibacterial wool

In this study, the antifelting and antibacterial features of wool samples treated with nanoparticles of titanium dioxide (TiO₂) were evaluated. To examine the antifelting properties of the treated samples, the fabric shrinkage after washing was determined. The antimicrobial activity was assessed through the calculation of bacterial reduction against Escherichia coli (Gram‐negative) and Staphylococcus aureus (Gram‐positive) bacteria. TiO₂ was stabilized on the wool fabric surface by means of carboxylic acids, including citric acid (CA) and butane tetracarboxylic acid (BTCA). Both oxidized samples with potassium permanganate and nonoxidized wool fabrics were used in this study. The relations between both the TiO₂ and carboxylic acid concentrations in the impregnated bath and the antifelting and antibacterial properties are discussed. With increasing concentration in the impregnated bath, the amount of TiO₂ nanoparticles on the surface of the wool increased; subsequently, lower shrinkage and higher antibacterial properties were obtained. The existence of TiO₂ nanoparticles on the surface of the treated samples was proven with scanning electron microscopy images and energy‐dispersive spectrometry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improving the dyeing properties of textiles via utilization of redox systems. I. Dyeing of wool and wool/polyacrylic blend fabrics with acid dye

Dyeing of wool and wool/polyacrylic fabrics with an acid dye, namely, Kiton Scarlet 4 R, was carried out in absence or presence of different redox systems. The latter were based on sodium, potassium, or ammonium peroxodisulphate or potassium periodate as oxidant and glucose, sodium thiosulphate, potassium pyrosulphite or thiourea as reductant. Regardless of the redox system used, the colour strength was far greater in presence than in absence of the redox system. Except in case of potassium periodate/glucose redox system, increasing the oxidant concentration up to 0.03 mol/l caused significant enhancement in colour strength. The same was observed upon increasing the temperature from 30 to 60°C as well as the time from 10 to 40 minutes. It is postulated that presence of the redox system alters the mode of dye attachment to the substrate. Association of the dye with the substrate, wool in particular, seems to involve covalent bonding beside the usual salt-linkage. Hence the approach presented is advantageous in producing dyeings with much higher colour strength and dye fixation at relatively low temperature.     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Surface modification of textiles by glow discharge technique: Part II: Low frequency plasma treatment of wool fabrics with acrylic acid

In this study, wool fibers are modified by low frequency plasma polymerization of acrylic acid regarding to its' hydrophobic character due to cuticular cells at their surfaces. Variables of the plasma glow discharge processes were power (40–100 W) and exposure time (5–45 min). The effect of plasma modification in the performance properties of wool were investigated on the basis of hydrophilicity of wool, average wrinkle recovery angle, and breaking strength. The surface chemical structures of fabrics were examined with x‐ray photoelectron spectroscopy. The hydrophobic wool fabric became hydrophilic after all plasma treatments except one (40W–5 min). Average wrinkle recovery angle of the treated fabrics were between 157 and 178°, while that of untreated fabric was 180°. The treated fabrics had a little bit lower angles according to the untreated fabric. However, even the lowest value as 157° means that the fabric has a good crease resistance property. The breaking strengths of fabrics were increased up to 26% after the plasma treatments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparatory processes for wool and wool blends

If a substrate for dyeing is incorrectly or inconsistently prepared, then the chances of achieving a right-first-time dyeing are greatly reduced. In this article, Robert Steele looks at some of the factors involved.     

Formaldehyde in textiles

A large amount of formaldehyde is used in the textile industry, particularly for imparting a crease-resist finish to fabrics. Recently concern has been expressed about its health risks. Mike Hewson looks at how the quantity of free formaldehyde and other potential irritant derivatives present on a fabric can be assessed.     

Jet printing for textiles

Since its inception, the use of jet printing technology for textiles has largely been confined to carpets. This restriction has been due to problems of low resolution and the difficulties of poor spread control, often resulting in sideways migration of the colour on flat fabrics. Ali Ahmed discusses these limitations and also highlights the potential of developing jet printing technology.     

Bioscouring of cellulosic textiles

A study on bioscouring of cotton yarn with the pectinase enzyme was carried out and the results compared with the usual alkali scoured material. The results indicate that the bioscoured yarn has lower percentage of non‐cellulosic constituents (impurities), higher tenacity, higher absorbency and the same whiteness after hydrogen peroxide bleaching as compared with the Solomatic bleached yarn. A similar study on cotton fabric indicates that a combined desizing and bioscouring is not feasible at least at ambient temperature. More work, however, is required to compare bioscouring followed by bleaching with the Solomatic or two step scouring and bleaching methods. One interesting finding is that the efficiency of washing of the desized fabric improves on adding ethylene diamine tetraacetic acid sequestrating agent in the wash liquor. Additional advantages of bioscouring are lower energy cost and more easily biodegradable effluent in comparison to alkali scouring.     

Determination of wool wax in raw wool by raman spectroscopy

A Raman spectroscopic method for the determination of wool wax content in raw wool has been developed. The analyses were performed on 250-mg wool samples by using a spectral component band resolution method. The method has a moderate sample throughput rate, is non-destructive and does not require the use of solvents. Samples ranging between 0.5 and 31% (w/w) wool wax were analyzed. The results obtained were compared with those obtained by a solvent extraction method. If the nonextractable lipid content of the wool is considered, the results of the Raman spectral and extraction methods were in excellent agreement. From a practical standpoint, the minimum detection limit of the method is 3% wax. In general, the precision of the Raman spectroscopic method was better than that obtained for the extraction method.     

Grafting onto wool

Summary In order to study the role of -SH group of wool in graft copolymerization, an attempt has been made to study grafting of acrylic acid (AAc) onto reduced wool in aqueous medium using ceric ammonium nitrate (CAN) as redox initiator. HNO₃ was found to catalyze the graft copolymerization. Reduction of wool was effected with thioglycolic acid (TGA) in aqueous medium. Percentage of grafting was determined as a function of concentration of (i) CAN, (ii) vinyl monomer (AAc), (iii) nitric acid, (iv) time and (v) temperature. Under optimum conditions, poly-(acrylic acid) was grafted to the reduced wool to the extent of 9.14%, the unreduced wool under optimum conditions afforded maximum grafting of poly(AAc) to the extent of 12.24%. Reduction of wool does not promote grafting of AAc in the presence of CAN.     

Grafting onto wool

Summary In order to ascertain the role of -SH groups in graft copolymerization of vinyl monomers onto Himachali wool fiber, an attempt has been made to graft copolymerize ethylacrylate (EA) onto reduced wool, in the presence of cerie sulfate (CS) as redox initiator in aqueous medium. Reduction of wool was carried out with thioglycolic acid (TGA) in aqueous solution. Percentage of grafting and percent efficiency were determined as functions of (a) Concentration of initiator (CS), (b) Concentration of monomer (EA), (c) Concentration of Sulfuric acid, (d) Time and (e) Temperature. Reduction of wool does not promote grafting of EA. The unreduced wool during ceric ion-initiated grafting of EA was reported earlier from this laboratory to produce more grafting. In ceric ion-initiated grafting of vinyl monomer onto wool, -SH groups do not play significant role. A plausible mechanism of grafting of EA onto reduced wool in the presence of ceric ion initiator has been suggested.     

Control of structured white textiles

The aim of this article was to study the instrumental measurement of whiteness related specifically to structured textiles. Both brightened and unbrightened white textiles have been investigated. A method of controlling the acceptability of whites is proposed specifically for highly structured textiles.     

Non-isothermal dyeing of wool

Kinetic models of the dyeing process are reviewed and diffusion of dye into the fibre is identified as the rate-determining step in most dyeing processes. A simpler approach to defining a linear exhaustion profile of acid dyes on wool fibres is proposed that takes into account non-isothermal kinetic models and analyses their possibilities of use. In this endeavour a novel dyeing rate constant is defined that appears to be characteristic of a particular dye class.     

Bleaching of wool grease

Bleaching tests on three dark wool greases show that, among many systems tested, only hydrogen peroxide and sodium chlorite have significant effects. Pale greases are obtained by adding controlled amounts of sulphuric acid, phosphoric acid, or sodium phosphate with the hydrogen peroxide; sulphuric acid and phosphoric acid improve the bleaching power of sodium chlorite.     

Heat-insulation of high-alumina wool

Conclusions It was established that heat-insulation tubes can be produced from high-alumina wool on the standard equipment of a plant manufacturing asbestos-cement products. The tubes can be used as ducts for molten nonferrous metals and as heat insulation for various components of heating furnaces operating at a temperature up to 1100°C.Translated from Ogneupory, No. 8, pp. 4–5, August, 1978.