Differential dyeing of wool fabric with metal‐complex dyes after ultraviolet irradiation

Experiments were conducted to investigate the ultraviolet irradiation of wool fabric as a pretreatment for differential dyeing. Wool fabric was irradiated using a medium‐pressure mercury lamp in order to obtain, on the irradiated area, increased dye uptake under the same dyeing conditions as untreated wool. The chemical modification of the fibre surface as a result of ultraviolet irradiation was confirmed by an increase in metal ion absorption and hydrophilicity, in agreement with Fourier Transform‐infrared–attenuated total reflectance spectra, although scanning electron microscopy showed that the fibre morphology was unaffected. A selection of 1:1 metal‐complex dyes was used to show the maximum colour difference between irradiated and untreated areas of the fabric. The experiments focused on two effects: a double face with the same shade but different depths (greater depth on the treated side), and a double face with different shades. The latter effect was achieved by dyeing the irradiated fabrics with mixtures of acid and metal‐complex dyes. Rubbing and washing fastness evaluations at 50 °C confirmed that the dyeings after irradiation with the selected 1:1 metal‐complex dyes scored identically to conventional dyeings.     

The use of poly(amidoamine) dendrimer in modification of jute for improving dyeing properties of reactive dyes

In this study, the poly(amidoamine) (PAMAM) G‐2 dendrimer was applied to the jute yarn. Fourier transform infrared spectrophotometry (FTIR) of the dendrimer‐treated jute yarn indicated that all carbonyl groups of the jute fiber have reacted with amino groups of the PAMAM dendrimer. Jute yarns which had been pretreated with PAMAM dendrimer displayed markedly enhanced color strength with reactive dyes, even when dyeing had been carried out in the absence of electrolyte or alkali. Dendrimer‐treated jute yarn showed much better light‐fastness than that of untreated jute yarn. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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.     

One‐bath union dyeing of a modified wool/acrylic blend with acid and reactive dyes

Pretreated wool/acrylic fibre was obtained by a facile amidoximation process. Fibre characterisation (nitrogen content, tensile strength, shrinkage, infrared spectra and X‐ray diffraction) proved the success of the pretreatment. Union dyeing of wool/acrylic fabrics with acid and reactive dyes, namely CI Acid Red 40, CI Acid Blue 25, CI Reactive Red 194 and CI Reactive Blue 25, was obtained using a one‐bath dyeing process. Different factors that may affect the dyeability of the blend fibre, such as dyebath pH, liquor ratio, temperature, time and dye concentration, were evaluated with respect to the dye exhaustion, fixation, colour strength, levelling and fastness properties. Excellent to good fastness was obtained for all samples, irrespective of the dye used. The result of the investigation offers a new viable method for union dyeing of wool/acrylic fibres in a one‐dyebath process.     

Ultrasound-assisted enzymatic scouring of jute optimised by response surface methodology and its natural dyeing

India is the largest producer of jute in the world and the use of this natural fibre in various value-added applications is gaining momentum. The use of white biotechnology involving enzymes for the efficient processing of jute is considered to boost its productivity. The present investigation deals with the pretreatment of jute by using ultrasound-assisted enzymatic scouring followed by bleaching and dyeing. The process showed optimum removal of impurities and improved water absorption capacity with minimal damage to fibre tensile strength. The process parameters and conditions were determined by response surface methodology, where weight loss of jute was kept as the main response. The optimised recipe obtained was 2.8% enzyme concentration, 1 g/L wetting agent at 55°C for 10 minutes at an ultrasound frequency of 40 kHz. The optimised recipe was compared with conventional high-temperature long-duration enzymatic scouring and was found to have an equal performance. Further, the scoured jute was dyed with a natural dye extracted from sappan wood and madder. Fourier Transform–infrared analysis was used for characterisation. The wash and light fastness of dyed jute yarn were evaluated and found to meet the industry norms.     

Natural dyeing and antibacterial activity of atmospheric‐plasma‐treated nylon 6 fabric

Atmospheric plasma treatment as an environmentally friendly method was employed to modify the surface properties and improve the absorption of natural cationic dye on to nylon 6 fabric. Nylon fabric was treated in atmospheric air plasma, and the surface characteristics of the fabric were evaluated using attenuated total reflection Fourier Transform‐infrared analysis, scanning electron microscopy, and a wicking test. The effects of plasma treatment and mordanting with copper sulfate on the dye uptake of the samples were investigated. Plasma‐treated and mordanted samples showed the highest colour strength when dyed. The antibacterial activity of samples was evaluated according to AATCC test method 100‐2004. Premordanting with copper sulfate showed a synergistic effect on the antibacterial properties of the dyed fabric. The plasma‐treated and copper‐sulfate‐mordanted sample showed acceptable antibacterial activity against both gram‐negative and gram‐positive bacteria when dyed with an extract from Berberis vulgaris, berberine.     

Investigation of the clean patterning possibilities on cotton socks through laser technology

The aim of this research is to reveal the effect of laser treatment at different resolutions (10, 20 and 30 dpi) and pixel times (80, 100 and 120 μs) on reactive dye uptake of cotton fabrics and the fastness values obtained. Yellowness index, Fourier Transform–infrared analysis, scanning electron microscopy analysis and bursting strength tests were applied to samples. The samples treated with laser were dyed in lighter shades than the untreated ones, with all three of the reactive dyes used in the experiments. In general, colour yield values decreased when the resolution and pixel time increased. However, no significant change was observed in washing, rubbing, light and perspiration fastness values. The possibilities of obtaining various patterns on cotton socks dyed with reactive dyes by laser treatment at different resolutions and pixel times were also investigated. According to the results, it was determined that if laser treatment was not applied to some parts of reactive dyed cotton socks, and 10 dpi 100 μs and 20 dpi 100 μs laser was applied to other parts of those socks, then it was possible to obtain patterns with different shades of the same colour on the socks. On the other hand, laser application after dyeing does not have a negative effect on fastness values. After determining the optimum conditions for the laser process, non-see-through tights were produced with cotton yarn on the front and polyester/elastane yarn on the back, and patterns were obtained by applying laser treatment before or after dyeing via sample scale industrial production.     

Application of D‐optimal design in the analysis and modelling of dyeing of plasma‐treated wool with three natural dyes

Both the dyeing and finishing of textiles with natural compounds are gaining increasing attention because of various environmental and health problems associated with the use of synthetic reagents. In this study, wool fibres were dyed with three natural dyes, namely, Arnebia euchroma, cotton pods and harmal seeds. Alum was used as the mordant, and samples were mordanted by the premordanting method. Oxygen plasma was employed for the surface modification of wool. Plasma treatment time, alum concentration, dyebath temperature and pH were selected as the process variables, and their effects on the K/S of the dyed samples were analysed using D‐optimal design. The surface topography, morphology and chemistry of the wool fibres after plasma treatment were studied by atomic force microscopy (AFM), scanning electron microscopy (SEM) and Fourier Transform–infrared spectroscopy (FTIR), respectively. FTIR confirmed the creation of new oxygen‐containing groups on the surface of wool fibres after plasma treatment. SEM and AFM images confirmed the surface etching and increase in the roughness of plasma‐treated fibres. Increasing the dyebath pH and temperature increased the K/S of the dyed samples. Increasing the amount of alum mordant increased the K/S of samples dyed with cotton pods but decreased the K/S of samples dyed with A. euchroma and harmal seeds. Increasing the plasma treatment time improved the K/S of samples dyed with A. euchroma and cotton pods but had no significant effect on the K/S of samples dyed with harmal seeds.     

Studies on mechanical and morphological behavior of hybrid nanoclay‐reinforced EPDM‐g‐TMEVS/PS blends

A new copolymer of tris(2‐methoxyethoxy) vinylsilane (TMEVS)‐grafted ethylene–propylene–diene elastomer (EPDM‐g‐TMEVS) has been developed by grafting of TMEVS onto EPDM by using dicumylperoxide (DCP) initiator. The linear polystyrene blends (EPDM‐g‐TMEVS/PS) based on EPDM‐g‐TMEVS have been synthesized with varying weight percentages of polystyrene in a twin‐screw extruder. In a similar manner, the dynamically vulcanized and nanoclay‐reinforced polystyrene blends have also been developed using DCP and organically modified montmorillonite clay separately by means of a twin‐screw extruder. The grafting of TMEVS onto EPDM at allylic position present in the third monomer of EPDM has been confirmed by Fourier Transform infrared spectroscopy. The effect of silane‐grafted EPDM and concentration of nanoclay on mechanical properties of polystyrene blends has been studied as per ASTM standards. The morphological behavior of these blends has been investigated using scanning electron microscope. It was observed that the incorporation of silane‐grafted EPDM enhanced the impact strength and the percentage elongation of linear‐ and dynamically vulcanized blends. However, the values of tensile strength, flexural strength, flexural modulus, and hardness of the blends were found to be decreasing with the increase of silane‐grafted EPDM. In the case of nanoclay‐reinforced polystyrene blends, the values of impact strength, tensile strength, flexural strength, flexural modulus, and hardness were increased with an increase in the concentration of nanoclay. XRD studies have been carried out to confirm the formation of nanoclay‐reinforced EPDM‐g‐TMEVS/PS blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Extraction of juglone from Pterocarya fraxinifolia leaves for dyeing,anti‐fungal finishing,and solar UV protection of wool

In many countries, the search for new sources of natural colourants has recently been intense. This paper deals with the extraction procedure, dyeing behaviour, antifungal activity, and ultraviolet protection of Pterocarya fraxinifolia as a new natural source of dyes. Juglone was found as the main extracted compound after characterisation by ultraviolet‐visible spectrophotometry and Fourier transform infrared spectroscopy. Mordanting and subsequent dyeing of wool with extracted juglone were then performed to study the dyeability and antifungal activities. Three metal salts, aluminium sulfate, copper sulfate, and iron sulfate, were used as chelating materials. The colorimetric properties of samples were evaluated using a reflectance spectrophotometer. Furthermore, the washing and light fastness properties were tested according to ISO 105‐CO3:1989 and ISO 105‐B01:2014. Interestingly, we found P. fraxinifolia to be a source of strong antifungal compounds against microorganisms. Extracted juglone also exhibited strong protection activity against solar ultraviolet rays.     

Studies on the dyeability and dyeing mechanism of polyurethane/clay nanocomposite filaments with acid,basic and reactive dyes

Polyurethane/clay nanocomposite (PUCN) filaments were spun by the dry‐jet‐wet spinning method. To prepare the PUCN filaments, 0.25, 0.50 and 1% of nanoclay on the weight of polyurethane were incorporated in the polyurethane dope. The interaction between clay and polyurethane was analysed by attenuated total reflectance–Fourier Transform‐infrared (ATR‐FTIR) spectroscopy. The structure and morphology of the PUCN filaments were analysed by wide‐angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM). Both the neat polyurethane and the PUCN filaments were dyed with different acid, basic and reactive dyes. The neat polyurethane filaments exhibited poor dyeability with all three classes of dyes. By contrast, the PUCN filaments showed a significantly higher dye uptake with all of the dyes used. Furthermore, the dye uptake increased significantly as the percentage of clay in the filaments increased, as indicated by the increase in the K/S values of the dyed filaments. The dyeing mechanism with all three dyes, as well as the increased dyeability of the PUNC filaments in comparison to those of the neat polyurethane filaments, was discussed.     

Dyeing behaviors of ionic liquid treated wool

In this article, a new class of “green” solvent—ionic liquid (IL) was employed to improve the dyeability of wool. The physical and chemical properties of the IL‐treated wool, such as surface morphology, wettability, and tensile strength were first analyzed, and then the dyeing properties of IL‐treated wool were investigated in terms of dyeing rate, dyeing exhaustion at equilibrium, color depth, and color fastnesses. The scanning electron microscope (SEM) images showed eroded marks on IL‐treated wool fiber surfaces. The water contact angle of the fabric treated with IL at 100°C decreased from 118.6° to 106.4°. The tensile strength of IL‐treated wool fibers was slightly decreased when the treating temperature was less than 100°C. Dyeing kinetics experiments revealed that the IL treatments greatly increased initial dyeing rate, shortened half‐dyeing time, and time to reach dyeing equilibrium. The final exhaustion and color depth of IL‐treated wool were also increased accompanying with slightly decreased color fastness. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of carbon black on properties of rubber nanocomposites

Polymer based nanocomposites were prepared using brominated poly(isobutylene‐co‐paramethylstyrene) (BIMS) rubber and octadecyl amine modified montmorillonite nanoclay. The effect of nature and loading of carbon black on these nanocomposites and the control BIMS was investigated thoroughly using X‐ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and mechanical properties. The addition of 4 parts of the modified nanoclay to 20 phr N550 carbon black filled samples increased the tensile strength by 53%. Out of the three different grades of carbon black (N330, N550, and N660), N550 showed the best effect of nanoclay. Optimum results were obtained with the 20 phr filler loading. For comparison, china clay and silica at the same loading were used. Fifty‐six and 46% improvements in tensile strength were achieved with 4 parts of nanoclay added to the silica and the china clay filled samples, respectively. N330 carbon black (20 parts) filled styrene butadiene rubber (SBR) based nanocomposite registered 20% higher tensile strength with 4 parts of the modified nanoclay. In all the above carbon black filled nanocomposites, the modulus was improved in the range of 30 to 125%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 443–451, 2005     

Effects of alkali and ultraviolet treatment on colour strength and mechanical properties of jute yarn

In this study, jute yarns were treated with an aqueous alkali solution and ultraviolet light to improve dyeability. Ultraviolet light treatments were carried out at an air pressure of 1 atm, under water and vacuum, and all the samples were dyed with reactive dyes. Virgin samples and treated jute yarns were analysed by Fourier Transform–infrared spectroscopy. K/S values were determined by a reflective spectrophotometer and used to establish the fixation values and colour strength of the dyed samples. The tensile mechanical properties of the samples were also measured by a tensile testing apparatus and were compared with the virgin samples. Alkali treatment resulted in a reduction in carbonyl group concentration. However, atmospheric ultraviolet light treatment increased carbonyl group concentration. Dyeability and dye fixation values for atmospheric and underwater ultraviolet light‐treated samples increased. Furthermore, the loss of tensile strength for alkali‐treated samples was much greater than others (up to 50%) in comparison with ultraviolet light‐treated samples.     

Effect of ammonia on madder‐dyed natural protein fiber

Of all the beautiful reds in nature, the only one vegetable source of good dyes ever discovered by man is madder. In this research natural protein fibers (i.e., wool yarns) were dyed with madder and then treated with different ammonia solutions. A UV–visible spectrophotometer was used to measure the absorbency of the remaining ammonia solution. The absorption curves showed the absorption transfer to the visible region. FTIR spectroscopy studies indicated that the changes in intensity at the peaks occurred when the madder‐dyed yarns were treated with ammonia solutions. The results of color measurement in the CIELAB system showed that the darkness of samples increased with an increase in the ammonia percentage in the solution. The vertical wicking test was also carried out on the madder‐dyed yarns and the ammonia‐treated samples. The results showed that the ammonia treatment causes a decrease in the wicking rate. A change of color was observed on the dyed samples when wash‐fastness tests were carried out. The results of light‐fastness tests showed more fading of the madder‐dyed yarns after ammonia treatment. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2704–2710, 2004     

Evaluation of mechanical,morphological, and biodegradable properties of hybrid natural fiber polymer nanocomposites

Hybrid natural fiber polymer nanocomposites were prepared using various natural fibers (kenaf, coir, and wood), polypropylene, and montmorillonite nanoclay through the hot compression method. The effects of fiber hybridization and nanoclay content on the physico‐mechanical and biodegradable properties of the synthesized composites were investigated. Fourier‐transform infrared and scanning electron microscopic analyses indicated that the structure and surface morphology of composites were transformed after fiber hybridization and the subsequent nanoclay incorporation. X‐ray diffraction pattern revealed that the percent crystallinity of hybrid nanocomposites significantly increased. Furthermore, the tensile strength and tensile modulus also significantly improved for the hybrid nanocomposites due to the addition of montmorillonite nanoclay. The biodegradability and water absorption tests were conducted. The results show that biodegradability of the nanocomposites decreased and water absorption increased due to the addition of montmorillonite nanoclay. POLYM. COMPOS., 38:583–587, 2017. © 2015 Society of Plastics Engineers     

Synthesis,spectral properties and dyeing on polyester of monoazo dyes from indol‐2‐one derivatives

Three series of phenylazo disperse dyes were prepared by coupling diazotised 4‐aniline dyes with 5‐indol‐2‐one dyes. The structures of these dyes were determined by proton nuclear magnetic resonance, Fourier Transform–infrared and elemental analysis. The effects of solvent on the ultraviolet–visible absorption spectra of these dyes were studied. The dyes displayed a λ_max shift of between 399 and 438 nm. The dyes were finally applied in the dyeing of polyester fibres in order to investigate their colour range and dyeing properties. Most of the dyes displayed high rubbing fastness and good washing and sublimation fastnesses on polyester fibres.     

Improving the dyeability of wool by treatment with chitosan

A study of pretreatment of wool fabrics with chitosan by a pad-dry method has been carried out. The pretreatment effectively eliminates differences in dyeing behaviour between damaged and undamaged wool fibres, with an increase in the rate of dye uptake and the exhaustion of acid and reactive dyes. Penetration of the fibre by dyes has been followed using fluorescence microscopy and the role of the chitosan coating in the dyeing process clarified. Similar colour fastness properties were obtained on both untreated and chitosan-treated wool fabrics. The chitosan coating on wool fabrics has been examined by scanning electron microscopy. Evidence for the presence of chitosan was sought using a colorimetric method. It is believed that an approximately uniform and adherent chitosan sheath is formed on individual wool fibres.     

Modification of polypropylene fibres with cationic polypropylene dispersion for improved dyeability

Polypropylene (PP) fibres are important hydrophobic fibres which are used in the production of functional textiles such as sports textiles. The absence of functional groups and low polarity make PP fibres difficult to dye, thus mass coloration during fibre extrusion is the major technique applied today. However, the disadvantage of mass coloration is the low flexibility and the demand to produce high volumes. A new method to modify the surface of PP fibres utilises the deposition and thermal fixation of cationic PP dispersion. Through padding and thermal fixation of a cationic PP dispersion, dyeable 100% PP fibres can be obtained. The effects of fixation temperature, and of the amount of dispersion used on the modified fibres were studied using Fourier Transform‐infrared spectroscopy, laser scanning microscopy, dyeing experiments with CI Acid Red 151, and by determining selected fastness properties. The results indicate the potential of this new method to produce surface‐modified 100% PP fibres, which can be dyed in conventional acid‐dyeing processes and therefore used in fibre blends, for example in combination with wool.     

The influence of copper(II) ions on wool photostability in the dry state

It has been hypothesised that the presence of trace metals in wool, notably copper and iron, has an influence on the formation of free radicals under irradiation and thereby affects the photostability of wool and wool products, particularly in the wet state. There has been limited research evaluating the influence of copper ions on wool photodiscoloration. This study examined the relative photodiscoloration of wool bound with varied amounts of copper(II) ions under UVA, UVB and blue light irradiation in the dry state. Total reflectance and visible/near‐infrared absorbance spectra, tryptophan‐type fluorescence (λ_ex = 295 nm, λ_em = 340 nm) and photoinduced chemiluminescence emissions of natural wool and copper(II)‐treated wool were characterised and contrasted. CIELAB colour space, D1925 yellowness and CIE whiteness values measured from irradiated wool samples indicate that wool treated with copper(II) solution at a higher concentration yellowed faster and experienced greater overall colour changes under UVA and UVB irradiation, whereas copper(II)‐treated wool seemed to be more photostable than untreated natural wool under blue light irradiation. It was also observed that binding copper ions to wool resulted in decreased tryptophan‐type fluorescence and photoinduced chemiluminescence emissions relative to untreated natural wool.