Wan Yunus Wan Ahmad

Puncture resistance of natural rubber latex unidirectional coated fabrics

A study was conducted on the puncture resistance of high-strength nonwoven natural rubber latex (NRL)-coated fabrics. High strength unidirectional (UD) polyethylene fabrics were coated using single dipping (SD), double dipping (DD), and triple dipping (TD) methods. The puncture resistance of the uncoated and coated fabrics was determined by measuring the force needed to penetrate the fabrics using a blunt probe. The mechanisms and modes of deformation involved during penetration were observed as well. In comparison with the uncoated fabrics, the SD, DD, and TD NRL coated fabrics gave higher puncture resistance of 39%, 47%, and 62%, respectively. The increments of the penetration force were proportional with the increase in the NRL-coated fabric thickness. For the uncoated fabric, the force given by the probe resulted in yarns stretching and yarn slippage upon penetration. However, the NRL-coated fabrics were not severely damaged but resulted in a curvature formed at the frontface of the fabric with minimal backface deformation. From the observations, the modes of failure were similar among the NRL-coated fabrics, that is, fiber stretching, delamination of NRL layer, and stretch marks on the fabric surface. The NRL layer acted as a protective sheath and increases the energy absorption and elasticity characteristics of the UD fabric.

Application of Bacterial Pigments as Colorant

In the last decade, investigations about possible use of natural dyes in textile dyeing processes have been carried out by various research groups. Various kind of natural dyes (e.g. Hibiscus mutabilis, Quercus infectoria and Cassia tora L.) were used to dye different types of materials (e.g. cotton, jute, wool, silk and leather) normally in the presence of mordant (e.g. alum, copper sulfate and ferrous sulphate). Studies on the dyeing techniques were attempted using both conventional (alkaline, acidic or neutral baths) and non-conventional methods (ultrasonic, microwave, sonicator and supercritical carbon dioxide fluids). The degree of dyeing was normally compared based on the colorfastness properties which can be defined as the property of a pigment or dye, or materials containing the coloring material, to retain its original hue, without fading, running or changing when wetted, washed, cleaned or stored under normal conditions when exposed to light, heat or other influences. Essentially, this means that different dyes will have different fastness on different materials.

Uniaxial failure resistance of square-isotropic 3D woven fabric modelled with finite element analysis

The article presents an extensive experimental test and finite element simulation of plain 1/1 woven fabric subjected to uniaxial loading. Square woven fabric is configured to allow systematic investigation of weave effects under uniaxial tensile load. The geometric fabrics models consisting of warp and weft yarns are imported to finite element analysis package, ABAQUS, for mechanical performance simulation. Simulated and experimental stress-strain validation of plain is reported to have strong positive correlation of 0.9986 and 0.999 in warp and weft direction, respectively. Further analysis is performed on the validated models such as stress distribution groups and maximum stress regions.

Fastness properties and colorimetric characteristics of low temperature dyeing of natural dyes from the barks of Ixonanthes icosandra Jack on polyester fabric

This paper reports on low temperature dyeing of polyester fabrics of natural dye extracts from the barks of Ixonanthes icosandra Jack. The barks were extracted using Boiling Water and Solvent (Methanol) Extraction methods. The dyeing process was conducted using exhaustion method at 85°C for 60 minutes. Three types of mordant were used by metacrome or simultaneous addition of mordant and dye in the dyebath. The dyed samples were measured using spectrophotometer to analyse the shades obtained with regards to L*a*b* values and K/S values (colour strength). The samples were also compared in terms of their ability to withstand washing, perspiration, rubbing/crocking and light. The results showed that dyed fabrics from the solvent extraction method gave higher K/S values in comparison with the dyed fabrics from the boiling water extraction method. The fastness properties of the dyed samples ranged from moderate to good rating except for lightfastness which gave poor rating.

Quasi-static puncture resistance of unidirectional coated fabric

High strength nonwoven fabric in the form of unidirectional structure are being used in ballistic protection applications due to their light weight and flexibility. In this study, natural rubber latex (NRL) was used as a coating material on unidirectional fabrics. It was found that the mechanical properties of the NRL coated unidirectional fabrics can be improved by adding fillers in the NRL compounding. Multiwall carbon nanotubes (MWCNTs) dispersion in several concentrations of 3 wt%, 5 wt% and 7 wt% were added into the NRL. The effects of filler loading of the MWCNTs in NRL were investigated under quasi-static penetration resistance test. In general, it was shown that the forces needed to penetrate the NRL coated fabric increases with higher content of filler loading and were higher in comparison with uncoated fabric. The NRL coated unidirectional fabrics with 7 wt% MWCNTs gave about 44% higher penetration resistance in comparisons with uncoated fabric. Several modes of fabric failure were observed after the quasi-static penetration resistance such as yarn stretching, yarn breakages as well as peeling off of NRL layer.

The activated carbon as anti-odour coated and pigment printed fabric

The different amount of activated carbon of 5%, 10% and 15% from coconut and oil palm shells in powder form were applied to the polyester and cotton fabrics by pigment printing and coating technique to investigate their anti-odour properties. The treated fabrics were exposed to onion odour for 24 hours before the odour tests were conducted. The odour tests were conducted to measure the effectiveness of treated fabric according to ISO Standards and making use of Portable Electronic Nose 3 (PEN 3) device. The results showed that, fabrics containing activated carbon are able to reduce odour that was picked up by the fabrics. The coated activated carbon fabrics gave better result than the printed activated carbon fabrics. The higher concentration of activated carbons on the fabrics generated lower rating of odour intensity and odour annoyance which also lower the odour of onion on the fabrics.

Nano Natural Dyes from Melastoma Malabathricum L.

In this study, natural colours were produced from Melastoma Malabathricum L.’s (Senduduk) plant. The dyes were extracted from the petal part of the plant using solvent extraction method of acidified methanol and methanol. The natural colours were then converted into powder form of nano size scale using a ball mill grinder. Silk fabrics were used as the substrate and dyed using several natural and synthetic mordant. The use of different solvents for extraction and mordant for dyeing resulted in different colour shades on the silk fabrics. The color fastness to washing tests revealed colour fastness to washing ranging from 3 – 4/5 and the change in color ranging from 3/4 – 4/5. The findings will benefit and promote the dyeing and printing industry such as batik manufacturers and local fashion industry in using natural dyes. On the other hand, dyes from plants can also be used as an alternative to synthetic dyes for dyeing natural silk fibers.

Comparison of electrical physical and mechanical properties of textile composites using microwave nondestructive evaluation

Composites are expensive and destructive test methods are normally applied to determine their physical and mechanical properties. For textile composites, a nondestructive test (NDT) could save time and save cost if the physical properties such as moisture content, weave architecture, void content and fiber volume fraction can be deduced from electrical properties. Also, there would be savings if mechanical properties such as tensile stress and elastic modulus could be determined by NDT methods. In this research, microwave NDT (MNDT) techniques such as measurement of complex permittivities are used for correlation with physical and mechanical properties. For textile composites made from E-glass, Kevlar and carbon fiber, we have measured reflection coefficients, transmission coefficients and dielectric properties using a free-space microwave measurement system. Epoxy has been used as a resin. Experimental results are reported for dielectric constants and loss tangents of textile composites. Also, measured physical and mechanical properties of textile composites are reported.

Tensile and Flexural Properties of Composites Made from Spinning Waste

ABSTRACT Spinning especially combed yarn produces considerable waste fibre. These fibres are sold at very low price for fillings. An investigation of converting these wastes to some form of value-added material was successful in forming a composite material made from natural fibre. Cotton combing noils and blowing waste were fabricated into thin composite boards using polyester resin at room temperature utilising a compression method. Tests on tensile and flexure properties of these composites were evaluated against 100% polyester resin plaques. It was found that composites made from cotton waste were stronger than polyester without the reinforcement. Some possible applications of these composites are thin boards or panels that can be used to replace wood and fibre-board products.

Dyeing of Polyester Using Natural Colorant from Melastoma malabathricum L.

Nowadays, interests on natural colorant have increased as the public are more aware and concern to environmental-related issues. In the continuing replacement of synthetic colorant, applications of natural colorant have extended to synthetic fibres. In this study, Melastoma malabathricum L. was extracted through boiling and ultrasound-assisted extraction (UAE). The colorant from UAE was dried in an oven before being converted into powder form using ball mill grinder. The colorant produced was dyed on polyester fabric at 85 °C. The polyester fabric was treated with sodium hydroxide as an alkaline treatment and chitosan prior to dyeing in an attempt to increase the dye uptake. The evaluation of the dyed fabrics was measured using colour spectrophotometer and tested for washfastness. Samples dyed using the UAE method gave lower value of L* which indicate higher dye uptake and darker colour. The fabric which was treated with sodium hydroxide gave deeper shade in comparison with the fabric treated with chitosan. The ratings for colourfastness to washing were between 3 and 5 which show moderate to good range.