C.W.M. Yuen

Development of Cosmetic Textiles Using Microencapsulation Technology

In recent years, textile materials have been found in applications in the cosmetics field. A new sector of cosmetic textiles is introduced and several commercial cosmetic textile products are currently available in the market. On contact with human body and skin, cosmetic textiles are designed to transfer an active substance for cosmetic purposes. The principle is achieved by simply imparting the cosmetic and pharmaceutical ingredients into the fabric of clothing so that with the natural movement of the body, the skin is slowly freshened and revitalised. Microencapsulation technology is an effective technique used to control the release properties of active ingredients that prolong the functionality of cosmetic textiles. This paper will address the historical background of microencapsulation technology, its significant advantages and the most commonly used microencapsulation methods. Some typical examples of commercially available microencapsulation based cosmetic textile products will also be examined. R...

Artificial neural network approach for predicting colour properties of laser-treated denim fabrics

In this study, artificial neural network (ANN) and linear regression (LR) approaches are proposed for predicting colour properties of laser-treated denim fabrics. Denim fabrics were treated under different combinations of laser processing parameters, including pixel time (μs), resolution (dot per inch) and grayscale (lightness percentage) as inputs. Colour properties, including colour yield (K/S sum value), CIE L*, a* and b* values and yellowness index were predicted as outputs in these approaches. Later, the prediction performances of two approaches were compared and the statistical findings revealed that ANN approach was able to provide more accurate prediction than LR approach, especially for L value. Moreover, among the three input variables, grayscale (lightness percentage) was found to be the most important factor affecting colour properties of laser-treated denim fabrics.

Optimization of electroless nickel plating on polyester fabric

Electrical conductivity is an important property of electroless nickel plated fabric. The optimized electroless nickel plating method can provide useful information for textile industries to obtain optimum surface resistance and stable plating. In this study, a screening experiment with factorial design and response surface method (RSM) with central composite design (CCD) was used to optimize the electroless nickel plating on polyester fabric. A two-level full factorial design (FFD) was used to determine the effects of five factors, i.e. the concentrations of nickel sulfate, sodium hypophosphite and sodium citrate, pH and temperature of the plating solution on surface resistance of the electroless nickel plated fabric. It is found that the nickel sulfate concentration and temperature of the plating solution are the most significant variables affecting the surface resistance of electroless nickel plated fabric. The optimum operating condition is finally obtained by using a desirability function. The test for reliability for predicting response surface equations shows that these equations give an excellent fitting to the observed values. In addition, the deposit composition, surface morphology, crystal structure and electromagnetic interference (EMI) shielding effectiveness (SE) were studied. The EMI SE of the nickel plated polyester fabric obtained under the optimal condition is about 60 dB at the frequency ranging from 2 to 18 GHz.

A study of metal oxide on antimicrobial effect of plasma pre-treated cotton fabric

Cotton, a natural fibre that consists of cellulose, is highly popular because it is sweat-absorbing and comfortable to wear. However, cotton fabrics provide an excellent environment for microorganisms to grow, owing to their ability to retain moisture. Therefore, numerous chemicals have been used to enhance anti-microbial activity of cotton textiles. This paper reports results of use of silver oxide (Ag2O) or zinc oxide (ZnO) as a catalyst in the antimicrobial formulation (halogenated phenoxy compound (Microfresh, MF)) and a binder (Microban, MB) for improved treatment of cotton fabrics and minimisation of side effects of the treatment. In addition, from the morphological study, plasma technology was employed to roughen the surface of the materials to improve loading of metal oxides on the surface. Moreover, the characteristic infra-red bands related to plasma-treated cotton produced results different from untreated fabric, implying plasma treatment can improve hydrophilicity of the fabric. Mechanical strength of the specimens was also increased by plasma treatment. Meanwhile, the research showed that the control fabric slightly inhibited the growth of S. aureus because of the bleach residues on fabric surface. On the other hand, anti-bacterial activity of MF-MB-treated specimen, especially in the presence of metal oxide catalyst, was enhanced, providing a slightly larger zone of inhibition. Moreover, plasma gas contains reactive oxygen species that can enter the cell, eventually causing its death. The hydrophilic nature of carbonyl groups present in oxygen plasma pre-treated specimens also increased the anti-microbial activity after treatment with MF-MB.

Effects of deposition parameters of electroless copper plating on polyester fabric

Properties of electroless copper-plated polyester fabric mainly depend on the plating bath constituents/conditions. The nickel serves to catalyze the copper deposition when hypophosphite is used as a reducing agent. In this study, the effects of deposition parameters including additive NiSO4 concentration and pH on microstructure and properties of the electroless copper plating on polyester fabric using hypophosphite as a reducing agent were investigated. The results show that at a higher NiSO4 concentration, the copper content present in the coating decreases whereas the nickel content increases slightly. On the other hand, the copper content present in the coating increases, whereas the nickel content and phosphorus decreases with respect to the rise of pH. The morphology of the copper deposits show that the particle size increase with respect to the rise of NiSO4 concentration and pH. The XRD patterns indicate that the copper-plated polyester fabrics are crystalline. In addition, there is a decrease in the surface resistance and an increase in the electromagnetic interference (EMI) shielding effectiveness (SE) with respect to the rise of Ni2+ concentration and pH of the solution as a result of gaining a greater weight in the deposits. The results suggest that the copper-plated polyester fabrics have a great potential application as an EMI shielding material.

Polyester metallisation with electroless silver plating process

In this paper, electroless silver plating process for polyester was reported. The electroless silver plating is basically divided into four stages including pre-cleaning, sensitisation, electroless silver deposition and post-treatment. As the electroless silver plating stage is the key stage in affecting the brilliant appearance and various functional properties such as conductivity and ultra-violet protection, we will study the effect of process variables, i.e. amount of silver nitrate (AgNO3), concentration of ammonium hydroxide (NH4OH), concentration of sodium hydroxide (NaOH) and process temperature, using increased amount of silver in fabric surface as an indicator, for optimising the electroless silver plating process for possible industrial application. Experimental results revealed that amount of silver nitrate (AgNO3)=1.77×10−3 mole; concentration of ammonium hydroxide (NH4OH)=6.25 %; concentration of sodium hydroxide (NaOH)=0.008 g/ml and process temperature=25 °C can give the best electroless silver plating for polyester fabric. The surface characteristics of the electroless silver-plated polyester fabric were evaluated by scanning electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction analysis. Meanwhile, the performance properties of the electroless silver-plated polyester fabric were measured by CIE L*, a* and b* values, conductivity as well as ultraviolet protection. The experimental results would be discussed thoroughly in this paper.

An analysis of some physical and chemical properties of CO2 laser-treated cotton-based fabrics

The aim of this study was to investigate the feasibility of the effect of CO2 laser technology on some physical and chemical properties of cotton-based fabrics. The cotton and cotton/polyester blended fabrics used in this study were treated with different combinations of laser processing parameters, i.e., resolution (52, 60 and 68xa0dpi) and pixel time (110, 120, 130 and 140xa0μs). After laser treatment, the surface structures of the fabric samples were evaluated by scanning electron microscope. It was confirmed that pores and cracks were formed on the laser-treated cotton fibres and their sizes varied with the change of laser processing parameters. However, the change occurring on cotton/polyester blended fabrics was found to be different such that the pores of cotton fibres were covered by the melted polyester with uneven flat regions being created. The results of fabric weight and fabric thickness revealed that laser treatment altered the weight of both cotton and cotton/polyester blended fabrics. However, the fabric thickness change of cotton/polyester blended fabrics was not steady when the laser processing parameters varied. Although laser treatment reduced the whiteness of both cotton and cotton/polyester blended fabrics, the whiteness was still acceptable. In addition, the laser processing parameter could affect the tensile strength of cotton and cotton/polyester blended fabrics. Surface chemical changes of cotton and cotton/polyester blended fabrics induced by laser irradiation were observed and analysed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results revealed that the hydroxyl C–O was found disappeared and the ether –O– stretches were reduced in both types of fabrics. Finally, it was proved by the solubility test that during laser treatment, the cotton fibres would be etched away.

Objective measurement of hand properties of plasma pre-treated cotton fabrics subjected to flame-retardant finishing catalyzed by zinc oxide

In the present paper, flame resistance property is imparted to cotton fabrics by N-methylol dimethylphos-phonopropionamide (Pyrovatex CP New, FR), melamine resin (Knittex CHN, CL), phosphoric acid catalyst (PA), and ZnO/nano-ZnO co-catalyst. The study shows that effectiveness of the FR-CL-PA reaction to form a crosslinked structure is enhanced by the co-catalytic reaction, resulting in enhancement of fabric’s compressional recovering ability. However, the low pH reaction weakened the fabrics, resulting in poor tensile strength and toughness, stiffer hand feel, brittle and tendered polymer layers, a less spongy fabric structure, and a roughened fabric surface with fuzzy fibrils. In addition, atmospheric pressure plasma jet (APPJ) was used to enhance materials properties by sputtering or etching effect. The roughening effect of plasma treatment enhances tensile properties of treated specimens. Nevertheless, the positive effect is negligible after post-treatment with flame-retardant agents. Moreover, the increased inter-yarn friction enhances the subjective stiffness of fabric and the rigid effect is even worse for plasma pre-treated cotton specimens subjected to flame-retardant treatment. However, plasma pre-treated specimens have a compressible structure after post-treatment with flame-retardant agents. Moreover, neutralization of flame-retardant-treated specimens helps minimize side effects of acidic finishing, irrespective of tensile and compression properties. The process also minimizes shear and bending rigid effect by removing unattached metal oxides from the fabrics.

Colour Properties of Plasma-Induced Ozone Fading of Cotton Fabric

This study concerned with colour fading of cotton fabric by plasma-induced ozone treatment. Cotton knitted fabrics were dyed with reactive dye of red colour with a depth of 0.5% and were subjected to ozneo generated by a plasma machine for colour fading. In order to investigate the colour properties of the plasma-induced ozone treated cotton fabric. The plasma-induced ozone treatment was conducted with different parameters: (i) air concentration = 10%, 30%, 50% and 70%; (ii) water content in fabric = 35% and 45% and (iii) treatment time = 10 minutes, 20 minutes and 30 minutes. After the plasma-induced ozone treatment, the colour properties of the fabric were measured by spectrophotometer under illuminant D65 to obtain the CIE L*, CIE a* and CIE b* values.

Optimising the Electroless Nickel Plating Process for Textile Application

In this paper, the optimisation of electroless nickel plating is investigated through the Orthogonal Array Testing Strategy. It was found that the electroless nickel plating process at the deposition stage with various parameters, i.e. temperature = 40°C, time = 20 minutes and pH = 10, is the most effective method in improving the metal adhesion performance. The performance of nickel-plated polyester fabrics was found to be dependent on the amount of nickel particles adhered on the fabric surface. The properties of optimised nickel-plated polyester were enhanced in term of fabric weight, fabric thickness and tensile strength. However, there was a moderate decrease in tearing strength and crocking fastness.