Tensile behaviour of wool fabric as a function of fabric pH

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 is similar to the variation in fabric hygral expansion previously observed. Fabric stress-strain curves at different pHs show 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 confirm the fact that the strength of wool fabric is at a maximum when the pH of the fibres is close to the isoelectric point.

Photochromic coloration of wool fabric

A method has been developed for producing photochromic wool fabric by applying a layer of hybrid silica containing a photochromic dye onto wool fibres. A number of different hybrid silicas were prepared by the sol-gel technique involving co-hydrolysis and co-condensation of alkyltrialkoxysilanes together with 3-glycidoxypropyltrimethoxysilane. With the dye Photorome II, it was possible to obtain a photo chromic coating which showed fast optical response. The coating had only a slight effect on the fabric handle. The durability of the coating appeared to be acceptable, at least for fashion wear.

The robustness of objective fabric pilling evaluation method

Previously, we proposed a new method to identify fabric pilling and objectively measure fabric pilling intensity based on the two-dimensional dual-tree complex wavelet reconstruction and neural network classification. Here we further evaluate the robustness of the method. Our results indicate that the pilling identification method is robust to significant variation in the brightness and contrast of the image, rotation of the image, and 2 i (i is an integer) times dilation of the image. The pilling feature vector developed to characterize the pilling intensity is robust to brightness change but is sensitive to large rotations of the image. As long as all fabric images are adjusted to have the same contrast level and the sample is illuminated from the same direction, the pilling feature vectors are comparable and can be used to classify the pilling intensity.

New methods for objective evaluation of fabric pilling by frequency domain image processing

Fabric pilling is a serious problem for the apparel industry. Resistance to pilling is normally tested by simulated accelerated wear and manual assessment of degree of pilling based on a visual comparison of the sample to a set of test images. A number of automated systems based on image analysis have been developed. The authors propose new methods of image analysis based on the two-dimensional wavelet transform to objectively measure the pilling intensity in sample images. Initial work employed the detail coefficients of the two-dimensional discrete wavelet transform (2DDWT) as a measure of the pilling intensity of woven/knitted fabrics.

This method is shown to be robust to image translation and brightness variation. Using the approximation coefficients of the 2DDWT, the method is extended to non-woven pilling image sets. Wavelet texture analysis (WTA) combined with principal components analysis are shown to produce a richer texture description of pilling for analysis and classification. Finally, employing the two-dimensional dual-tree complex wavelet transform as the basis for the WTA feature vector is shown to produce good automated classification on a range of standard pilling image sets.

The effect of pH on wool fiber diameter and fabric dimensions

Wool fabrics are often treated under conditions of varying pH in dyeing and finishing processes. It is known that in air the dimensions of wool fabrics change with the amount of fiber swelling at different regain. In this work, it has been shown that a similar relationship between fiber swelling and fabric dimensions existed in water at different pH values. The diameters of Merino and Corriedale wool fibers in water at different pH values were measured with an OFDA 2000 fiber diameter analyzer, fitted with a specially constructed accessory liquid cell. The results showed that the mean diameters of swollen wool fibers in water varied with pH. Minimum swelling was obtained in the range pH 5-7. It was found that the dimensions of wool fabric in water were dependent on the pH. The changes in fiber diameter in water could be attributed to changes in ionic interactions between charged acid and basic groups in wool protein with variations in pH.

Photochromic wool fabric by sol-gel coating

This thesis investigates the possibility of producing photochromic wool fabrics using a silica sol-gel coating method. Silicas made from sol-gel methods are uniquely suited to host photochromic dyes for developing colour-changing wool. The achieved photochromic effects have opened a new product area for fashion effects on wool textiles.

Objective evaluation of fabric pilling propensity

Fabric pilling is of critical importance to the textile industry. This study developed an objective pilling evaluation method using computer image techniques. The applicability and robustness of the proposed method were investigated based on actual knitted fabrics, the results are very accurate and repeatable.

Controlled amine functionalization and hydrophilicity of a poly(lactic acid) fabric

The surface of PLA fabric has been successfully modified by pulsed plasma polymerization of heptylamine (PPHA) giving increased hydrophilicity and achieving a sufficient level of primary amine functionality (3.5%) for practical application in biotechnology. This is the first report that the density of primary amine (-NH2) in PPHA, quantified by chemical derivatization, can be controlled by selection of pulsed plasma conditions. The duty cycle and the average RF power were the key parameters for achieving both a higher density of primary amine and increased hydrophilicity.

Performance of an objective fabric pilling evaluation method

In previous work, we established the principle of objective fabric pilling evaluation based on two-dimensional dual-tree complex wavelet transform (2DDTCWT) image reconstruction and non-linear classification using a neural network. This proof-of-principle work was performed using standard pilling test images. Here, we demonstrate the practical operation of the objective pilling evaluation method using a large set of real fabric pilling samples. We show that piling classification results from a trained multiple-layer perceptron neural network achieve a regression correlation of approximately 96% with the corresponding human expert pilling ratings.

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.