Predicting the pilling tendency of wool knits

This work investigates the application of artificial neural network modeling (ANN) to model the relationships between fiber, yarn, and fabric properties and the pilling propensity of single jersey and rib pure wool knitted fabrics based on the ICI Pilling Box method. Validation of the model on an independent validation data set suggests that the accurate prediction of pilling propensity is possible with the best performing model achieving a correlation with the subjectively rated pilling grades of approximately 85%. Importantly, it is also illustrated that a larger training set can lead to a marked improvement in the accuracy of predictions.

Reducing the pilling propensity of wool knits with a three-step plasma treatment

A three-step plasma treatment, including surface activation with argon, surface functionalization with oxygen and then thin film deposition using a pulsed plasma polymerization of hexamethyldisiloxane (HMDSO), was used in low-pressure plasma to improve the pilling resistance of knitted wool fabric. The pilling propensity of the treated samples was investigated and compared with the pilling propensity of untreated, argon activated and oxygen functionized samples and argon and oxygen plasma-treated samples that were afterwards subject to continuous wave plasma polymerization of HMDSO. With the three-step treatment, a pilling grade of four was achieved for the treated wool fabric, while that of untreated and other plasma-treated was two and three, respectively. For the three-step plasma-treated sample, a uniform HMDSO polymer coating of 300 nm thickness was obtained; X-ray photoelectron spectroscopy (XPS) showed the presence of the silicone element, and Fourier transform infrared (FTIR) spectroscopy confirmed the chemical structure of the coating. No apparent differences were found in the whiteness index between the treated and untreated wool knits, but there was deterioration in the bursting strength and handle of the plasma-treated wool samples.

Prediction of wool knitwear pilling propensity using support vector machines

The propensity of wool knitwear to form entangled fiber balls, known as pills, on the surface is affected by a large number of factors. This study examines, for the first time, the application of the support vector machine (SVM) data mining tool to the pilling propensity prediction of wool knitwear. The results indicate that by using the binary classification method and the radial basis function (RBF) kernel function, the SVM is able to give high pilling propensity prediction accuracy for wool knitwear without data over-fitting. The study also found that the number of records available for each pill rating greatly affects the learning and prediction capability of SVM models.

Recent research on natural fibres and textiles

This paper provides an overview of recent research on a range of natural fibres and textiles. The focus is on work carried out at Deakin University’s Centre for Material and Fibre Innovation, which is a multidisciplinary research centre with over 100 researchers. The fibres include hemp, wool, silk, and alpaca fibres. Research on yarns, fabrics, and fine powders made from wool and silk fibres are briefly discussed also.

The within-fibre diameter variation of wool has been examined systematically, which highlights the importance of this hard-to-measure fibre attribute. A relationship between hemp fibre fineness and residual gum content has been established, which provides a rapid means of assessing the residual gum content in the degummed hemp fibres. Silk and wool fibres have been converted into ultrafine powders for advanced applications. The Resistance to Compression (RtC) behaviour of wool and alpaca fibres has been closely examined, which challenges the belief that RtC is a good indicator of fibre softness. Ways of reducing the hairiness of natural fibre yarns, predicting the pilling propensity of wool knits, and functionalising fabrics for superhydrophobicity and photochromic or colour changing effects are discussed.

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.

Woolgrowers, brokers and the debate over the sale of the Australian wool clip, 1920-1925

Prior to the First World War, the selling of the Australian wool clip rested firmly in the hands of the large woolbroking firms. An agreement between the British and Australian governments during the war saw many of the wool-selling functions of broking firms taken over by the Central Wool Committee. At the conclusion of hostilities, brokers moved to regain their role in the market. However, market conditions had changed. On an international level, traditional trading relationships had broken down, leaving commodity markets unstable and prices unpredictable. On a local level, woolgrowers had benefited from the wartime orderly marketing scheme and the high price guaranteed by the British government for their wool clip. As a result, they had begun to demand a greater role in the selling arrangements of their clip. This paper investigates the debates over the sale of the wool clip in the 1920s and how woolbrokers and growers eventually arrived at an understanding as to the manner in which the market should operate.

Characterization of conductive polyprrole coated wool yarns

Wool yarns were coated with conducting polypyrrole by chemical synthesis methods. Polymerization of pyrrole was carried out in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption, and electrical properties of the yarn upon coating with conductive polypyrrole are presented. Coating the wool yarns with conductive polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive polypyrrole. The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction in the moisture regain of the wool yarn. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone sulfonic acid resulted in a large reduction in the resistance of the yarn.

Resistance to compression behavior of alpaca and wool

This study compares the resistance to compression behavior of wool and alpaca fibers. It shows that alpaca fibers have a much lower resistance to compression than wool, and there is little correlation between the resistance to compression and the curvature for alpaca fibers. Yet for wool fibers, the correlation between resistance to compression and curvature is very strong and positive. The differences in fiber curvature and scale profiles of alpaca and wool, together with the test method for resistance to compression, may explain their different resistances to compression.

Frictional and tensile properties of conducting polymer coated wool and alpaca fibers

Wool and alpaca fibers were coated with polypyrrole by vapor-phase polymerisation method. The changes in frictional and tensile properties of the single fibers upon coating with the conductive polymer are presented. Coating a thin layer of polypyrrole on the alpaca and wool fibers results in a significant reduction in the fiber coefficient of friction, as the conducting polymer layer smooths the protruding edges of the fiber scales. It also reduces the directional friction effect of the fibers. Depending on the type of fiber, the coating may slightly enhance the tensile properties of the coated fibers.

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.

The hairiness of worsted wool and cashmere yarns and the impact of fiber curvature on hairiness

In this study, a range of carefully selected wool and cashmere yarns as well as their blends were used to examine the effects of fiber curvature and blend ratio on yarn hairiness. The results indicate that yarns spun from wool fibers with a higher curvature have lower yarn hairiness than yarns spun from similar wool of a lower curvature. For blend yarns made from wool and cashmere of similar diameter, yarn hairiness increases with the increase in the cashmere content in the yarn. This is probably due to the presence of increased proportion of the shorter cashmere fibers in the surface regions of the yarn, leading to increased yarn hairiness. A modified hairiness composition model is used to explain these results and the likely origin of leading and trailing hairs. This model highlights the importance of yarn surface composition on yarn hairiness.

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.

Determination of cashmere and wool fibre scale frequency by analysing diameter profiles with fast fourier transform

This paper describes a potentially faster and cheaper method of determining fibre scale frequencies. The method uses the single fibre analyser (SIFAN) to  determine the along the fibre diameter profile. This information is then analysed by the Fast Fourier Transform technique using computer software. The paper shows the close association between the mean scale frequencies determined by this method and the traditional approach using SEM.

Cashmere and wool cortical cells

This paper proposes that instead of the expensive and difficult task of examining the morphology of fibre cuticle scales that an alternative approach of examining the internal morphology of cortical cells may be faster and cheaper. Preliminary data were presented and further work is required.