Dyeing properties of PVA/superfine wool powder blend filaments

Polyvinyl alcohol/superfine wool powder blend filaments were prepared to improve teh dyeing properties of polyvinyl alcohol (PVA) filaments. The average size of superfine wool powder was 2.01 um. SEM microphotgraphs showed good compatibility between superfine wool powder and PVA matrix. The PVA/superfine wool powder blend solution showed good spinningability. With the incerease in superfine wool powder content, the dye uptake, a* value and K/S value of PVA/superfine wool powder blend filaments increased steadily. It was worth noting that the dyeing properties of blend filaments were almost similar with that of superfine wool powder when powder content was 33.3%

Photochromic wool fabric by sol-gel coating and photochromism

The application of photochromism in textiles has potential to create new opportunities to develop fancy colour-changing effects in fashionable textiles, as well as smart garments capable of protecting wearers from the effects of UV irradiation and responding to environmental changes. This book presents a coating method for achieving quick and obvious photochromic effects on wool fabrics using conventional photochromic dyes and hybrid silicas. It covers details about fabricating different types of photochromic dye-silica coatings, measuring their optical performance, assessing some physical characterisations of the coatings, and measuring the effects of the coatings on fabric performance.

Prediction of wool knitwear pilling propensity using data mining techniques

This thesis examined the application of data mining techniques to the issue of predicting pilling propensity of wool knitwear. Using real industrial data, a pilling propensity prediction tool with embedded trained support vector machines is developed to provide high accuracy prediction to wool knitwear even before the yarn is spun!

Ultrasonic treatment of wool

These ultrasonic cleaning trial results for stain removal and fibre property changes look at wool scouring and laundering, and examine the use of ultrasonic irradiation during wool cleaning with an aim to improve the cleaning process and reduce its impact on the environment. It contains fibre images, single fibre tensile and bending abrasion results.

Use of low-level plasma for enhancing the shrink resistance of wool fabric treated with a silicone polymer

This study examines the effects of an atmospheric pressure plasma (APP) pre-treatment on the shrink resistance of wool fabric treated subsequently, by the pad/dry method, with an aqueous emulsion of the amino-functional polydimethylsiloxane, SM 8709. Optimal shrink resistance (with no impairment of fabric handle) was obtained after a low-level plasma treatment (1-3 s exposure time), using 5% of the polymer emulsion. Higher levels of silicone polymer could be used to achieve shrink resistance in the absence of a plasma pre-treatment, but the fabric handle would be adversely affected. X-ray photoelectron spectroscopy (XPS) studies showed that the bulk of the covalently bound surface lipid layer was removed after a plasma exposure time of 30 s. For treatment times of 3 s or less, however, the removal was incomplete, suggesting that optimum shrink resistance (after treatment with the silicone polymer) was associated with the modification of the surface layer rather than its complete destruction. Scanning electron micrographs (SEMs) revealed that the plasma pre-treatment did not lead to any physical modifications (such as smoothening of the scale edges), even for long exposure times, and had no significant impact on the extent or nature of the inter-fibre bonding of the polymer. Confocal microscopy showed uniform spread of polymer on single fibres. It is concluded that the main impact of the plasma pre-treatment was to enhance the distribution of polymer both on and between fibres and to improve adhesion of polymer to the fibre.

Ultrasonic scouring of wool and its effects on fibre breakage during carding

Ultrasonics has shown the potential to reduce the cost and environmental impact of textile processing. This work investigates the impact of ultrasonic scouring on fibre entanglement caused during the scouring process. Levels of fibre entanglement were quantified by measuring fibre length using OFDA4000 after carding. A significant reduction in fibre entanglement after ultrasonic scouring was observed and this was due to a reduced fibre migration in the wash bath when compared with the mechanical agitation seen in conventional scouring process. Fibre cuticle scale damage resulting from the ultrasonic irradiation may also have contributed to the reduction in fibre entanglement. A reduced level of fibre entanglement from ultrasonic wool scouring leads to a reduction in fibre breakage during carding.

Modelling of fibre-diameter-dependent light scattering to determine diameter corrections for colour measurement of wool

In this paper, fibre-diameter-dependent light scattering during measurement of wool colour was quantified using the extended multiplicative signal correction technique. Furthermore, a simple-to-apply model has been developed to correct each of the CIE (International Commission on Illumination) X, Y and Z values obtained from colour measurement of fibrous masses. The model was successfully applied to both polypropylene (PP) and wool fibres, though different parameter values were used in each case, indicating different patterns of internal light scattering between PP and wool fibres. After the model corrections, the diameter dependence of measured wool yellowness (Y - Z) was either eliminated or significantly reduced for each of seven sheep flocks distributed widely over the wool-growing regions of Australia.

Influence of trace-metals on the colour and photostability of wool

This study expands the knowledge of the mechanisms that cause wool to yellow. It established that metals in wool influence the production of free radicals and the extent of degradation and yellowing of photo-irradiated wool. It also examined the relationship between the colour and trace metal content of fleece wool.

Ageing effect of plasma-treated wool

Atmospheric pressure plasma treatment of wool fabric, with a relatively short exposure time, effectively removed the covalently bonded lipid layer from the wool surface. The plasma-treated fabric showed increased wettability and the fibres showed greater roughness. X-ray photoelectron spectroscopy (XPS) analysis showed a much more hydrophilic surface with significant increases in oxygen and nitrogen concentrations and a decrease in carbon concentration. Adhesion, as measured by scanning probe microscopy (SPM) force volume analysis, also increased, consistent with the more hydrophilic surface leading to a greater meniscus force on the SPM probe. The ageing of fibres from the plasma-treated fabric was assessed over a period of 28 days. While no physical changes were observed, the chemical nature of the surface changed significantly. XPS showed a decrease in the hydrophilic nature of the surface with time, consistent with the measured decrease in wettability. This change is proposed to be due to the reorientation of proteolipid chains. SPM adhesion studies also showed the surface to be changing with time. After ageing for 28 days, the plasma-treated surface was relatively stable and still dramatically different from the untreated fibre, suggesting that the oxidation of the surface and modification or removal of the lipid layer were permanent.

Thermal and mechanical properties of ultrasonically treated wool

Wool fabrics, ultrasonically treated in various chemical conditions and for different time durations, were analysed for thermal properties by thermo-gravimetric analysis and differential scanning calorimeter, in comparison with the untreated fabric. Fabric mechanical properties, such as bending and tensile performance, and changes in fibre morphology were also evaluated before and after ultrasonic treatment.It is found that wool treated with ultrasonics at the appropriate time, has less mass loss and a higher thermal degradation temperature than that without ultrasonic treatment or with prolonged ultrasonic treatment. Resistance to thermal degradation is reduced when wool is ultrasonically treated in the presence of alkali. Differential scanning calorimeter analysis shows that while ultrasonic treatment has little effect on fibre crystallinity, an appropriate treatment can provide wool with increased water absorption. Ultrasonic treatment stiffens wool fabric to some extent when the treatment time is prolonged. The addition of detergent alone to the ultrasonic bath has little effect on fabric tensile behaviour, whereas a treatment with both detergent and alkali produces severe fibre damage and significant loss of fabric tensile strength.

Antibacterial activity of capsaicin-coated wool fabric

Fabrics made from natural fibers, such as wool and cotton, are susceptible to attacks from micro-organisms, which may damage the fabrics and harm the human body. Antimicrobial finishing of natural textile products may involve harmful and non-environmentally friendly chemicals. In this study, a natural antibacterial agent, capsaicin, was coated on the surface of wool fabrics by a sol-gel process. The antibacterial properties of coated fabrics were evaluated against test bacteria Escherichia coli according to the American Association of Textile Chemists and Colorists (AATCC) method and standard American Society for Testing and Materials (ASTM) E2149-01. Compared with the control group (sol-gel coated fabric without capsaicin), the capsaicin-coated fabric inhibited bacterial growth markedly after 24 hours incubation at 37°C. The antibacterial efficiency after laundry washes was also investigated. Good durability to washing of capsaicin on fabric was achieved by the sol-gel coating technique.

Effect of atmospheric plasma treatment on pad-dyeing of natural dyes on wool

Plasma treatment is an emerging surface modification technique that alters dye uptake of wool without using chemicals or water for pre-treatment. Padding is an established continuous dyeing technique known for its efficient use of water, time and energy. This study combined these two techniques for colouration of wool fabric using two natural dyes derived from the Acacia plant family. The investigation focused on the effects of plasma treatment and obtaining unique patterning effects. Helium (100%) and a mixture of helium and nitrogen (95%/5%) were used as the plasma gases under atmospheric conditions. Plasma treated wool fabric was padded with the above natural dyes. Copper sulphate and ferrous sulphate were applied on the dyed fabric as mordant yielding neutral shades of beige and grey respectively. Up to a 30% enhancement of dye adsorption on plasma treated wool substrate was observed as compared to untreated sample for both gases used. This higher adsorption indicates the hydrophilic character of the natural dyes used. Key performance parameters such as fastness to washing, rubbing and light were tested and found to be satisfactory. A single process tone-on-tone pattern was achieved by controlling the plasma exposure of treated area. This study concluded that a merger of natural dyes with modern plasma treatment and padding techniques for wool colouration was feasible.

Effects of pH on the stress-strain properties of wool fabric

In wool dyeing and finishing processes, fabric is often treated under conditions of different pHs and is subjected to a variety of physical and chemical environments. This work investigates fabric tensile properties at three different fabric pHs. Wool fabric extensibility under a 5 N/cm load was observed to be greatest at the wool isoelectric point of pH 4.8 and lower at both pH 2.1 and pH 7.2. The impact of pH on fabric extensibility was found to be similar to the variation in fabric hygral expansion previously observed. Fabric stress–strain curves at different pHs showed that for a given fabric extension level, the work required to stretch a fabric was less at pH 2.1 than at pH 4.8. These results suggest that the strength of wool fabric is at maximum when the pH of the fibres is close to the wool isoelectric point and that for consistency, the pH of fabric should be adjusted before standard strength tests are carried out.

The effect of humidity and temperature on Wool Comfort Meter assessment of single jersey wool fabrics

The Wool ComfortMeter provides an objective measurement of the fabric-evoked prickle discomfort rating provided by wearers. This work aimed to quantify the sensitivity of the Wool ComfortMeter over a range of different temperature and humidity conditions to determine the recommended test conditions for its operation. The design was: three temperatures (notionally 20, 25 and 30°C) at three relative humidities (RHs, notionally 50, 65 and 80%) each with two replicates, using six different wool single jersey knits (mean fibre diameter 19.5–27.0 µm). As it was difficult to achieve exactly some of the extreme combinations of temperature and RH, some combinations were repeated, providing a total of 23 different assessment conditions. Data were analysed using restricted maximum likelihood mixed model analysis. The best fixed model included RH, RH2, temperature and the interaction of temperature and RH, accounting for 95% of the variation in Wool ComfortMeter readings. Wool ComfortMeter values were almost constant at 55–60% RH. Generally, the Wool ComfortMeter value reduced with increasing RH > 60% at temperatures of 25°C and 28.5°C as the regain of the fabric increased. However, at 20°C little change was detected as RH was increased from 50 to 80% as there were only small changes in fabric regain. The observed effects were in a good agreement with existing knowledge on the effect of regain on the mechanical properties of wool fibre. Wool ComfortMeter is best operated under standard conditions for textile testing of 65% RH and 20°C.