Variation in the softness and fibre curvature of cashmere, alpaca, mohair and other rare animal fibres

Softness of apparel textiles is a major attribute sought by consumers. There is surprisingly little objective information on the softness properties of rare animal fibres, particularly cashmere, alpaca and mohair. Samples of these and other rare animal fibres from different origins of production and processors were objectively measured for fibre diameter, fibre curvature (FC, crimp) and resistance to compression (softness). While there were curvilinear responses of resistance to compression to FC and to mean fibre diameter, FC accounted for much more of the variance in resistance to compression. Fibre type was an important determinant of resistance to compression. The softest fibres were alpaca, mohair and cashgora and all of the fibres measured were softer than most Merino wool. Quivet, llama, camel, guanaco, vicuña, yak wool, bison wool, dehaired cow down and Angora rabbit were also differentiated from alpaca, mohair and cashmere. There were important differences in the softness and FC of cashmere from different origins with cashmere from newer origins of production (Australia, New Zealand and USA) having lower resistance to compression than cashmere from traditional sources of China and Iran. Cashmere from different origins was differentiated on the basis of resistance to compression, FC and fibre diameter. Cashgora was differentiated from cashmere by having a lower FC and lower resistance to compression. There were minority effects of colour and fibre diameter variation on resistance to compression of cashmere. The implications of these findings for the identification and use of softer raw materials are discussed.

Fibre properties affecting the softness of wool and other keratins

The emerging market for next-to-skin knitwear requires wool to satisfy the consumer’s tactile requirements for softness. The role of the fibre’s surface and physical properties on fibre and fabric softness was examined. The fibre’s cuticle properties were found to have a greater influence on softness than the fibre’s mechanical properties.

Evolution of structural and magnetic properties of Co–Fe based metallic glass thin films with thermal annealing

Ultra thin films based on CoFe were prepared from a composite target employing thermal evaporation. The microstructure of the films was modified by thermal annealing. The relationship between microstructure and magnetic properties of the films was investigated using techniques like glancing angle X-ray diffraction (GXRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The GXRD and TEM investigations showed an onset of crystallization of CoFe at around 373 K. The magnetic softness of the films improved with thermal annealing but at higher annealing temperature it is found to be deteriorating. Annealing inducedmodification of surface morphology of the alloy thin filmswas probed by atomic force microscopy (AFM). Surface smoothening was observed with thermal annealing and the observed magnetic properties correlate well with surface modifications induced by thermal annealing

An experimental study on fabric softness evaluation

Purpose – To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

Design/methodology/approach – A testing system was setup for fabric pulling force measurements and the testing parameters were experimentally determined. The specific pulling forces were compared with the fabric assurance by simple testing (FAST) parameters and subjective softness ranking. Their correlations were also statistically analyzed.

Findings – The fabric pulling force reflects the physical and surface properties of the fabrics measured by the FAST instrument and its ability to rank fabric softness appears to be close to the human hand response on fabric softness. The pulling force method can also distinguish the difference of fabrics knitted with different wool fiber contents.

Research limitations/implications – Only 21 woven and three knitted fabrics were used for this investigation. More fabrics with different structures and finishes may be evaluated before the testing method can be put in practice.

Practical implications – The testing method could be used for objective assessment of fabric softness.

Originality/value – The testing method reported in this paper is a new concept in fabric softness measurement. It can provide objective specifications for fabric softness, thus should be valuable to fabric community.

The softness of alpaca fibres

Softness is a unique selling point for luxury fibres such as alpaca. However, there is very little objective data on the softness of animal fibres. This study first establishes that the resistance to compression (RtC) behaviour of alpaca and wool fibres is quite different, and that the RtC method can not be used to examine the softness of different animal fibres. It then reports a new method for evaluating fibre softness. This method is based on the measurement of the force required to pull a fibre bundle through a series of parallel pins. This force, reflecting the combined effect of fibre surface properties, fibre diameter and rigidity, can achieve reasonable discrimination between fibres of varying levels of softness, such as alpaca and wool. Mechanisms responsible for the superior softness of alpaca fibres are discussed also.

A comparative study of the mechanical properties of wool and alpaca fibres

This study reports the latest research into alpaca and wool fibres. In particular, those properties that have received little attention in research literature have been examined. They include single fibre abrasion and bending fatigue, single fibre tensile properties, as well as resistance to compression behaviour. These properties are important because they affect the softness and pilling propensity of these fibres and the resultant fabrics. Clean wool and alpaca fibres were used in this study. Fibre abrasion/bending fatigue measurements were carried out using a Textechno FIBRESTRESS instrument. The resistance to compression (RtC) tests were carried out according to Australian Standard AS3535-1988. The results indicate that wool and alpaca fibres behave quite differently, even though both fibre types are of animal origin. Wool fibre resistance to compression decreases as fibre diameter increases while the opposite appears to occur for alpaca fibres. For both wool and alpaca the number of abrasion/bending cycles at fibre break increases with an increase in fibre diameter, it takes longer to break the alpaca fibres. Reasons for these differences have been postulated based on differences in fibre surface and structure between alpaca and wool.

A correlation study of subjective sensorial evaluation and objective softness measurement of wool fabrics

Comfort is one of the most important aspects of clothing, especially for next-to-skin garments such as shirts and trousers for summer. Sensorial comfort has a strong relationship with both the mechanical and surface properties of apparel fabric. A comfortable textile material should have properties of softness, smooth surface or texture, be pleasant to touch and very flexible. When assessing fabric handle subjectively, the assessor usually strokes the fabric surface with one or several fingers and squash the fabric gently in hand. Thus, the perception of such handle includes complex parameters of compression, tactile sensation and textural effect. In this work, we attempted to use a simple technique of objectively evaluating fabric softness related properties, by measuring the force required to pull a fabric strip through a series of parallel pins (the pulling force). We also subjectively rated the fabric handle. The correlation analysis showed very good agreement between the fabric pulling force and subjective hand rating.

Properties, processing and performance of rare and natural fibres : a review and interpretation of existing research results

A substantial up-to-date reference manual has been prepared which documents important issues for the supply chain of rare natural animal fibres. New developments in textiles have been included. Cashmere, mohair and camelid fibres have special properties of softness, smoothness and lustre, when compared with sheep wool. They also have other attributes which affect market prices and consumer perceptions, such as being rare and exotic luxuries, and are associated with expensive, comfortable and exclusive garments. These fibres add to the range of wool processing, and add value to wool textiles. Generally, knowledge about these animal fibres is limited, and research effort small compared with research into wool and other natural and man-made fibres. Compared with wool, rare natural animal fibres are more difficult and costly to process. Knowledge about processing these fibres is kept guarded as industrial knowledge. There are problems with clearly identifying rare natural animal fibres when goods are traded or fibres are blended, and fraud is a major concern for textile manufacturers and industry groups. Prickle discomfort in mohair and alpaca next-to-skin wear is a major concern for consumers and textile manufacturers. Natural colours, whiteness and yellowness of rare natural animal fibres are important fibre attributes for dyers and consumers, and the current products have both positive and negative colour attributes for processors. Past investments by RIRDC have made substantial gains in knowledge about fundamental and applied areas of knowledge on the properties, testing and processing performance of rare natural animal fibres.

Transglutaminase mediated grafting of silk proteins onto wool fabrics leading to improved physical and mechanical properties

Transglutaminases have the ability to incorporate primary amines and to graft peptides (containing glutamine or lysine residues) into proteins. These properties enable transglutaminases to be used in the grafting of a range of compounds including peptides and/or proteins onto wool fibres, altering their functionality. In this paper we investigated the transglutaminase mediated grafting of silk proteins into wool and its effect on wool properties. A commercial hydrolysed silk preparation was compared with silk sericin. The silk sericin protein was labelled with a fluorescent probe which was used to demonstrate the efficiency of the TGase grafting of such proteins into wool fibres. The TGase mediated grafting of these proteins led to a significant effect on the properties of wool yarn and fabric, resulting in increased bursting strength, as well as reduced levels of felting shrinkage and improved fabric softness. Also observed was an accumulation of deposits on the surface of the treated wool fibres when monitored by SEM and alterations in the thermal behaviour of the modified fibres, in particular for mTGase/sericin treated fibres which, with the confocal studies, corroborate the physical changes observed on the treated wool fabric. © 2006 Elsevier Inc. All rights reserved.

Study on microwave dielectric properties of epoxy resin mixtures used for rapid product development

This paper presents a preliminary study on the dielectric properties and curing of three different types of epoxy resins mixed at various stichiometric mixture of hardener, flydust and aluminium powder under microwave energy. In this work, the curing process of thin layers of epoxy resins using microwave radiation was investigated as an alternative technique that can be implemented to develop a new rapid product development technique. In this study it was observed that the curing time and temperature were a function of the percentage of hardener and fillers presence in the epoxy resins. Initially dielectric properties of epoxy resins with hardener were measured which was directly correlated to the curing process in order to understand the properties of cured specimen. Tensile tests were conducted on the three different types of epoxy resins with hardener and fillers. Modifying dielectric properties of the mixtures a significant decrease in curing time was observed. In order to study the microstructural changes of cured specimen the morphology of the fracture surface was carried out by using scanning electron microscopy.