Photochromic fibers and fabrics

Photochromic fibers and fabrics can change color in response to light radiation. They represent a smart textile having attracted much attention recently and showing potential applications in diverse areas. This review chapter gives an overview of the state-of-the-art techniques for the preparation of photochromic fibers and fabrics. The properties and applications of photochromic fabrics are also discussed.

Directional water transport fabrics with durable ultra-high one-way transport capacity

Fabrics with automatic one-way water transport ability are highly desirable for applications in daily life, industry, health, and defense. However, most of the studies on one-way water transport fabrics only report the qualitative water transport results. The lack of quantitative measure makes it hard to assess the directional transport quality. Here, it is proved that a hydrophilic fabric after being electrosprayed with a thin layer of hydrophobic coating on one side shows one-way water transport ability. By using moisture management tester, the water transport property is qualitatively characterized and the effect of hydrophobic fabric layer thickness on one-way water transport feature is examined. The hydrophobic fabric layer thickness is found to play a key role in deciding the one-way transport ability. When a plain woven fabric with an overall thickness of 420 μm and average pore size of 33 μm is used as fabric substrate, a hydrophobic fabric layer thickness between 22 and 62 μm allows the treated fabric to show a one-way droplet transport feature. A one-way transport index as high as 861 can be attained. The one-way water transport is durable enough to withstand repeated washing. This novel fabric may be useful for development of “smart” textiles for various applications.

Protection of silica-coated ZnO nanoparticles on pre-dyed polyester fabrics against photofading

This work was designed to investigate the ability of silica-coated ZnO (ZnO&SiO2) nanoparticles (NPs) as ultraviolet (UV) absorbers for protecting pre-dyed polyester fabrics against photofading. Despite that ZnO NPs are excellent UV absorbers, their strong photocatalytic activity limits the application in UV protection. In this study, a silica layer was coated onto ZnO NPs to form a physical barrier between the ZnO and a polyester substrate, which allowed effective UV shielding while minimising the harmful effects of photocatalytic activity on the substrate. The structure and optical proprieties of ZnO&SiO2 NPs were observed. The bare ZnO and ZnO&SiO2 NPs were, respectively, applied to polyester fabrics coloured with three kinds of dyes by a dip coating method. The photofading level of treated fabrics after exposure under simulated sunlight was evaluated. The ZnO&SiO2 NPs exhibited excellent protection on pre-dyed polyester fabrics against photofading.

Incorporating sustainability in textile effluent treatment facilities

Sustainable development encompasses environmental, social and
economic considerations. As such the stakeholders include industry, government, individuals and communities. When designing or operating an industrial plant, it is Insufficient to consider only the economic viability of the facility. This paper examines the background to current sustainability awareness and presents a case study that incorporates sustainability principles in the design of an efluent treatment plant for a textile plant. The likely design of the treatment system (electro flotation followed by filtration) will do more than just meet regulatory requirements, it will maximise possible reuse of water and so minimise environmental impact of the facility.

Characterization of conducting polymer coated synthetic fabrics for heat generation

Heat generation in fabrics coated with the conductive polymer polypyrrole was investigated. The PET fabrics were coated by chemical synthesis using four different oxidizing agent–dopant combinations. The samples from the four different dopant systems all show an increase in temperature when a fixed voltage is applied to the fabric. The antraquinone-2-sulfonic acid (AQSA) sodium salt doped polypyrrole coating was the most effective in heat generation whereas the sodium perchlorate dopant system was the least effective. The power density per unit area achieved in polypyrrole coated polyester–Lycra® fabric with 0.027 mol/l of AQSA acting as dopant was 430 W/m². The power density per unit area achieved for the sodium perchlorate system, using the same synthesis conditions, was 55 W/m².

Technical efficiency in Australian textile and clothing firms: evidence from the business longitudinal survey

This paper estimates technical efficiency of Australian textile and clothing firms based on the data obtained from the Business Longitudinal Survey (BLS) conducted by the Australian Bureau of Statistics (ABS). Using a Cobb Douglas stochastic production frontier the paper examines firm level technical efficiency in the time varying inefficiency effect model with technical inefficiency effects assumed as an independently distributed truncated normal variable. Estimates of the production frontier revealed significant but small elasticities of labour and capital for textile and clothing firms, respectively, and a negative (but insignificant) Hicks neutral technical change for both. Estimated coefficients of the explanatory variables for inefficiency effects indicated that technical efficiency varied significantly according to firms’ age, size, capital intensity, proportion of non-production to total workers and type of legal status. Predicted firm specific efficiency varied from 16 per cent to 95 per cent and mean efficiency ranged between 30 to 70 per cent. In view of these results policies have been suggested to improve technical efficiency of the firms as well as productivity growth of the sub sectors.

Soluble poly-3-alkylpyrrole polymers on films and fabrics

Conductive textiles with specific properties can be produced by the chemical polymerisation of a range of 3-alkylpyrroles in the presence of textiles. The morphologies of these coatings are altered from the traditional conductive coatings. Comparison using a SEM reveals substantial differences.

Generating heat from conducting polypyrrole-coated PET fabrics

Heating effects in polypyrrole-coated polyethyleneterephthalate (PET)-Lycra® fabrics were studied. Chemical synthesis was employed to coat the PET fabrics by polypyrrole using ferric chloride as oxidant and antraquinone- 2-sulfonic acid (AQSA) and naphthalene sulfonic acid (NSA) as dopants. The coated fabrics exhibited reasonable electrical stability, possessed high electrical conductivity, and were effective in heat generation. Surface resistance of polypyrrole-coated fabrics ranged from approximately 150 to 500 /square. Different connections between conductive fabrics and the power source were examined. When subjected to a constant voltage of 24 V, the current transmitted through the fabric decreased about 10% in 72 h. An increase in resistance of conductive fabrics subjected to constant voltage was observed

Predicting the pilling propensity of fabrics through artificial neural network modeling

Fabric pilling is affected by many interacting factors. This study uses artificial neural networks to model the multi-linear relationships between fiber, yarn and fabric properties and their effect on the pilling propensity of pure wool knitted fabrics. This tool shall enable the user to gauge the expected pilling performance of a fabric from a number of given inputs. It will also provide a means of improving current products by offering alternative material specification and/or selection. In addition to having the capability to predict pilling performance, the model will allow for clarification of major fiber, yarn and fabric attributes affecting fabric pilling.

Measuring the influence of fibre-to-fabric properties on the pilling of wool fabrics

This study ranks the contribution of various fibre, yarn and fabric attributes to the pilling of wool knitwear. On the basis of an artificial neural network modelling, a combination of sensitivity analysis, forwards/backwards search and genetic algorithms was used to identify the importance of various fibre/yarn/fabric input parameters. The three different techniques show broad similarities in their assessment of which input parameters are important or are not important in affecting fabric pilling. The ranking shows that fabric cover factor has the most effect on pilling, followed by yarn count and thin places, fibre length, yarn twist, etc. It is further illustrated that the directional trend of the predicted pilling outputs for a selection of inputs was in line with the expected behaviour. To verify the findings of input feature selection, input factors deemed to have a small effect on the predicted pilling output, such as fibre length and diameter variations and curvature, were removed and the subsequent performance statistically compared to the original multi-layer perceptron. Differences between the outputs predicted by the original and pruned models are found not to be statistically significant at the 5% significance level. Results from this study may help manufacturers and knitwear designers in choosing the most appropriate materials and structures to reduce the pilling propensity of wool knitwear.

Synthesis, polymerization and wool coating studies of 3-iso-butylpyrrole and 3-iso-pentylpyrrole

In a four-step method starting from pyrrole, the synthesis of 3-iso-butylpyrrole and 3-iso-pentylpyrrole, was achieved in 45 and 44% yields, respectively. Polymerization studies of these branched alkyl pyrroles are described and the results compared with those obtained for the unbranched structural isomers n-butyl and n-pentylpyrrole. A series of conductive textiles were produced by the chemical polymerization of the iso-alkylpyrroles using both solution and vapour polymerization techniques. Fabrics coated with poly-iso-alkylpyrrole formed using the solution polymerization method had a lower surface resistance than those formed using the vapour polymerization method. These conductivity results were in direct contrast to those previously obtained for 3-n-alkylpyrroles on fabrics. A remarkable crystal-like growth on the surface of the textile fabric was observed when solution polymerization of 3-iso-pentylpyrrole was employed—reinforcing the notion that subtle changes in monomer structure can drastically affect bulk polymer properties.

Polymerising pyrrole on polyester textiles and controlling the conductivity through coating thickness

The surface resistance of polypyrrole (PPy)-coated polyester fabrics was investigated and related to coating thickness, which was controlled by adjusting the reactant concentrations. The thickness of the coating initially increased rapidly followed by a steady increase when the concentration of pyrrole (Py) was larger than a concentration of approximately 0.4 mg/ml. The surface resistance decreased from 10⁶ to 10³ Ω with increase in pyrrole concentration within 0.2 mg/ml until the concentration reached a value of about 0.4 mg/ml, above which the rate of decrease diminished. The effect of initial treatment with monomer or oxidant prior to polymerisation reaction with regards to thickness and surface resistance was minimal. The immersion time of the textile into the monomer solution prior to polymerisation reaction did not have a significant effect on the abrasion resistance.

Conductive fabrics for heating applications

By coating textiles with electrically conductive organic polymers, we are able to produce functional, intelligent fabrics. These fabrics can be utilised in applications such as gas sensors, actuators, electromagnetic shielding, radar absorption, selected frequency filtering in indoor wireless applications, and heating applications where vital parts of the body can be heated without embedding any wiring through the fabric.

Heat generation in fabrics coated with the conductive polymer polypyrrole was investigated. The fabrics were coated by chemical synthesis methods by oxidizing the pyrrole monomer in the presence of the fabric substrate. Ferric chloride was selected as the oxidizing agent and anthraquinone-2-sulfonic acid (AQSA) sodium salt monohydrate as the dopant.

Conductive fabrics were characterized by resistivity measurements, scanning electron microscopy, thermal imaging, current transmission over a period of time and calculations of power density per unit area. Effects of reaction conditions on the electrical properties and heat generated are presented. Polypyrrole coated fabrics were stable and possessed high electrical conductivity. Resistivity values ranged from 100-500 ohms/square depending on the reaction parameters. When subjected to a constant voltage of 24V, the polypyrrole coated polyester-Lycra® fabric doped with AQSA reached a maximum temperature of 42°C and a power density per unit area of 430 W/m² was achieved.

Sources of productivity growth in Australian textile and clothing firms

This paper estimates the sources of productivity growth in Australian textile and clothing firms based on the Business Longitudinal Survey (BLS) from 1995 to 1998. Productivity growth estimates have been obtained for each sub-category of textile and clothing firms. Sources of growth in multifactor productivity (MFP) are examined with growth in technical efficiency and scale effects based on estimates of stochastic frontier production functions. Separate estimates of output growth have been compared with the productivity growth estimates for each of the product categories. MFP improved in all clothing firms and declined in textile firms over 1997–1998 by four-digit level of Australia New Zealand Standard Industrial classification Scheme (ANZSIC). MFP declined in most major categories of both textile and clothing firms in 1995–1997. Changes in technical efficiency mostly dominated scale effects in the overall direction of MFPG in both textile and clothing firms. The findings of the study provide evidence for policies for improving the firms' operative performance in the ongoing liberalised regime.