Dyeing kinetics of wool fabrics pretreated with a protease

Dyeing kinetics of wool fabrics treated with different concentrations of an enzyme of the protease type are studied in this work. Dyeing isotherms with an acid and a premetalised 2:1 dyestuff were carried out and the fit of several kinetic equations to the experimental results determined. The absorption rate constants and activation energies were calculated.     

Novel approach for antisetting of wool fabrics during dyeing

New antisetting agents are proposed for wool fabrics during dyeing at the boil, viz., dithiodipropanoic acid ( DTDPA) and dithiosalicylic acid (DTSA). DTDPA was found to be better than DTSA in the protection of wool during dyeing. The effect of the addition of these reagents to the dyeing bath of wool on some of its inherent mechanical properties was assessed. A proposed mechanism of reaction between the aforementioned dithiols and wool keratin is reported.     

Antimicrobial finishing of wool fabrics using quaternary ammonium salts

Durable antimicrobial wool fabrics were prepared by using a simple chemical finishing process. Carboxylate groups in wool protein were employed to form ionic interactions with cationic antimicrobial agents, such as cetylpyridinium chloride (CPC) and other quaternary ammonium salts, under the isoelectric point of wool protein, and such interactions were proven effective. The uptakes of the agents were dependent on their chemical structures, pH values of treatment solutions, concentration of the agents, and treatment temperature. The ionic interactions between the agents and the protein could survive repeated laundering, with CPC showing the best durability among three tested quaternary ammonium salts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1037–1041, 2004     

Antimicrobial finishing of wool fabrics with quaternary aminopyridinium salts

Quaternary aminopyridinium salts were employed in antimicrobial finishing wool fabrics. The effects of alkyl chain length in the salts, pH conditions of finishing baths, finishing time and temperature, and salt concentrations were investigated. The incorporated quaternary aminopyridinium salt molecules on wool were characterized by FTIR. The quaternary ammonium salt could form ionic interactions with anionic groups on wool, which contribute to the durable antimicrobial functions. All the finished wool fabrics exhibited antimicrobial efficacy against Escherichia coli. The washing durability of antimicrobial functions on the finished wool fabrics was also studied. ©2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 482–486, 2007     

A hemicyanine fluorescent reactive cationic dye: synthesis and applications on wool fabrics

A novel hemicyanine fluorescent reactive cationic dye was synthesised by the reaction between the free amino group of a hemicyanine fluorescent dye and 2,3‐dibromopropionyl chloride. The dye was characterised by proton nuclear magnetic resonance spectroscopy, high‐resolution mass spectrometry, ultraviolet‐visible absorption spectrometry, and single‐photon fluorescence spectrometry. The prepared dye was applied to wool fabrics to give fluorescent orange shades. The colour fastness of the dyed wool fabrics was tested. Results show that dyed fabrics using the novel hemicyanine fluorescent reactive cationic dye could be used as fluorescent clothing.     

Neutral dyeing of wool and wool/polyester blend fabrics using sulphatoethylsulphone reactive‐disperse dyes

Two models of temporarily anionic sulphatoethylsulphone reactive disperse dyes were applied to wool, polyester and wool/polyester blend fabrics at different dyeing pH. Maximum exhaustion values and colour yield were observed at pH 7. The results showed that reactive disperse dyes containing bis‐sulphatoethylsulphone reactive groups were more convenient for neutral dyeing of wool and wool/polyester blend fabrics if compared with a dye containing a mono‐sulphatoethylsulphone group. Excellent to very good wet fastness properties on all dyed fabrics were achieved.     

Microwave irradiation graft copolymerization of hydroxyethyl methacrylate onto wool fabrics

Hydroxyethyl methacrylate was grafted onto woolen fabrics by microwave irradiation in the presence of catalyst (NH₄)₂S₂O₈. Various parameters of the graft copolymerization reaction, namely, time, microwave intensity, catalyst, and monomer concentration, were optimized. The graft copolymerization was also compared with conventional heating graft copolymerization at the same condition. Microwave irradiation was shown to improve the reactivity of the monomer. The moisture regain decreased as graft add-on increased. The Max load and the strain at Max load increased as graft add-on increased. The infrared spectra showed an additional peak at 1700 cm⁻¹, confirming ester carbonyl groups of the monomer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2343–2347, 1998     

Topping of naturally dyed wool fabrics with different natural dye sources

Wool fabrics can be dyed with synthetic dyes and even with natural dyes. To present a different aspect to the coloration of wool, the current study was focused on a topping process (ie, the dyeing of wool that was already dyed) with different natural dye sources. For this purpose, the fabrics that were already dyed with a natural dye source were once again dyed with two different natural dyes. In bottom dyeing (bottoming), fabrics were dyed with hops (Humulus lupulus L.) in the presence of different mordanting agents. Then the dyed, washed and dried samples were once again dyed (topping) with two different natural dye sources. For topping, powdered madder and acorn were tested in direct dyeing of wool samples. Finally, the colour changes were analysed with the use of a spectrophotometer. The study demonstrates that such a process (ie, bottoming with hops in the presence of different mordanting agents and then topping with madder or acorn) can be a way of obtaining different shades and colours with sufficient/good fastness values by natural dyeing.     

Improving the properties of chemically damaged wool fabrics with carbohydrate polymers

Wool is a natural composite material consisting of keratin and keratin‐associated proteins as the key molecular components. During wool product processing, a variety of chemical and enzymatic reagents are used, the side‐effects of which can include the removal of the outside layers of the fiber (cuticle) and damage within the internal protein matrix of the fiber. This can reduce the mechanical strength and durability of wool fabrics. We report the use of neutral, cationic, and anionic carbohydrate polymers, namely 2‐hydroxyethyl cellulose, chitosan and alginate, as repair agents to improve the mechanical properties and morphology of wool fabrics damaged under harsh alkaline conditions. Tensile strength, peel adhesion, scanning electron micrographs, and fabric wettability evaluation reveal the cationic polymer, chitosan, to be most effective at remedying the effects of the alkaline treatment. The improved mechanical properties observed after chitosan treatment may offer viable remediation routes for adding value to processing‐damaged wool textiles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3105–3111, 2013     

Analysis of thermal performance of two fabrics intended for use as protective clothing

Tests were conducted on two fabrics intended for use in protective clothing: an aramid (used extensively in firefighter gear) and a modified viscose cellulosic fabric. Both were exposed to very high heat (temperatures above 400°C) and their performance as thermal insulators was assessed by the temperature transmitted through the fabric, both in their dry state and after being exposed to a water spray. Both fabrics performed satisfactorily, but the modified viscose fabric improved its thermal insulation properties when damp, while the aramid fabric remained unaffected (or perhaps negatively affected) by the water spray. Overall, the modified viscose fabric seemed a better thermal insulator than the aramid. © 1997 John Wiley & Sons, Ltd.     

Nano polyurethane based surface modification on the anti-felting functionalization of wool fabrics

Nano polyurethane (Nano PU) was used for the fabrication of multilayer nanocomposite film deposition on wool fabrics by electrostatic self-assembly to improve the anti-felting properties. Oppositely charged cationic poly (diallyldimethylammonium chloride) (PDDA) and anionic Nano PU were alternately deposited on the surface of wool fabrics. 8, 12 and 16 multilayer films of PDDA/Nano PU were deposited on the wool fabric surfaces using a padder. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (FTIR-ATR) and Scanning Electron Microscopy (SEM-EDX) were used to verify the presence of deposit nanolayers. Breaking strength, whiteness and yellowness value analysis was performed on the fabrics before and after the treatment with Nano PU by the electrostatic self-assembly method. The build-up of the multilayer films and the level of colour strength (K/S) achieved are discussed after the acid dyeing process. To examine the anti-felting properties of the multilayered fabrics, the fabric shrinkage after washing was determined.     

The effect of finishing on the mechanical and thermal properties of wool fabrics. Part1-the properties of piece-dyed fabrics

Changes in the handle-related deformation properties of wool fabric following piece dyeing were found to be related to the set imparted by the dyeing operation, and resulted primarily from dimensional changes in the fabric. When dyeing imparted large amounts of set to the wool, increased contraction during drying resulted in a heavier, more extensible fabric. Inhibiting set by dyeing at low pH, or by dyeing in the presence of an oxidising agent or cross-linker, reduced the effect. Objectively measured fabric surface properties and subjective assessment of smoothness were little affected by the conditions of dyeing and were far more dependent on the dry-finishing method used to set the fabric and, to a lesser extent, on the method used to pre-set the fabric prior to dyeing. The effect of extended dyeing on the mechanical properties of the fabric depended not only on the pH of dyeing but also on the nature of the dyeing machine.     

Influence of plasma sputtering treatment on natural dyeing and antibacterial activity of wool fabrics

In this paper, the effect of plasma sputtering treatment on the natural dyeing properties of wool and the possibility of substituting it for mordant treatment have been studied. We used madder and weld as natural dyes and copper sulfate (CuSO₄) as a metal mordant. We also used, copper as the electrode material, in a DC magnetron plasma sputtering device.     

Soil deposition on shrink-resist-treated wool fabrics in the presence of anionic and non-ionic surfactants

The deposition behaviour of carbon black on shrink-resist-treated wool fabric, and on untreated wool, in the presence of different mixtures of anionic and non-ionic surfactants has been investigated. Two types of surfactant mixtures were studied; sodium dodecylbenzenesulphonate and sodium dioctylsulphosuccinate were used as anionic surfactants and Triton X-100 as a non-ionic surfactant. An electrokinetic study was also carried out, under similar conditions; the zeta potential was obtained, which was related to the amount of deposition found. From these zeta potential measurements the surface charge density was determined.     

Improving the hydrophilic properties of wool fabrics via corona discharge and hydrogen peroxide treatment

Corona discharge has been widely applied to modify the surfaces of polymers. In this study, corona discharge was combined with a hydrogen peroxide treatment to improve the hydrophilic properties of wool fabric. Scanning electron microscopy photographs showed that the tip of wool scales was etched after corona discharge and that parts of the scales were peeled off after the hydrogen peroxide treatment. The surface hydrophilic properties of the wool fabric were improved greatly by corona discharge. Increases in the discharge voltage and the number of treatment passages enhanced the hydrophilic properties dramatically, but the improved properties deteriorated with increases in the number of washing cycles and storage time. The hydrogen peroxide treatment could improve the hydrophilic properties and especially the wicking properties of the wool fabric. The fabric became weaker and flexible with an average weight loss of 3% after the hydrogen peroxide treatment. A combination of corona discharge treatment and the hydrogen peroxide treatment made the wool fabric absolutely hydrophilic; the water penetration time of the treated fabric was less than 1 s even when the fabric was washed for several cycles or stored for 6 months. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Use of lipoprotein lipase in the improvement of some properties of wool fabrics

Wool fabrics were pretreated with hydrogen peroxide in the presence of different stabilisers; namely, sodium silicate, magnesium sulphate and imino disuccinic acid sodium salt. The effect of stabiliser type and concentration on the properties of the treated wool were studied. Imino disuccinic acid sodium salt was found to be the most effective stabiliser for hydrogen peroxide when added to the bleaching bath of wool fabric. The effect of after‐treatment of the pre‐oxidised wool fabric with commercially produced lipoprotein lipase enzyme on its dyeability with acid and reactive dyes, as well as on some of its physico‐mechanical properties, was assessed. Chemical and microscopic analyses were conducted to assess changes in the chemical composition of wool treated with this system. Wool fabrics treated with hydrogen peroxide/imino disuccinic acid sodium salt/lipoprotein lipase enzyme exhibit improved wettability and, hence, dyeability with both acid and reactive dyes, as well as enhanced resistance to felting shrinkage and pilling, without severe deterioration in the fabric’s inherent properties.     

The effect of corona treatments on the hygral expansion of wool worsted fabrics

The effect of dry corona and aqueous treatments on the hygral expansion of wool gabardine has been investigated. Increasing the severity of the corona treatment produced a concomitant reduction in the hygral expansion of the fabric. X-ray photoelectron spectroscopy has been used to study the chemical modification of the wool fibre surface.     

Preparation,thermal properties and permeabilities of aluminum-coated fabrics destined for thermal radiation protective clothing

In this study, radiant reflective, flame retardant and water vapor permeable coatings were fabricated on aramid fabric (AF) for thermal radiation protective clothing by using a simple cost-effective coating method, which included an aluminum paste, APP-PER-MEL and a silk fibroin powder in the TPU solution system. The permeability, flame retardancy, thermal stability, radiative spectral reflectance, as well as RPP of these prepared fabrics were characterized and compared with the pure AF and aluminum-foiled AF (AF-AF). Results show that the newly developed aluminized AF had rather high permeability, and the permeable capability would be further enhanced with the additive of silk fibroin powder. The flame retardancy (FR) of the coated fabric sample was also achieved by introducing an intumescent FR system. In contrast to the pure AF, the aluminum-coated AF provided higher levels of radiation protection in RPP testing. This was further confirmed by the fact that aluminum-coated AF exhibited comparative high average reflectivities (more than 0.7) in the radiant spectral range of 1547 nm to 2500 nm. Thus, the aluminum-coated AF prepared by functional coating method exhibit great and competitive practicability in thermal protective clothing due to their excellent moisture comfort and radiant thermal protection.     

Time optimization of ultraviolet–ozone pretreatment for improving wool fabrics properties

Wool fabrics were exposed to ultraviolet (UV)–ozone treatment for different periods. After exposure, the fabrics were analyzed by Fourior transform infrared spectroscopy (FTIR). Also, the crystallinity and amorphousity regions were followed by an X‐ray diffraction technique. The results were correlated by mechanical properties measurements. After a certain period of exposure, the dyeability and printability were improved because these abilities are strongly related to the percentage ratio of crystallinity regions to amorphousity regions in wool fabrics. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1469–1476, 2002