Feltability of cashmere and other rare animal fibres and the effects of nutrition and blending with wool on cashmere feltability

Felting is a unique attribute of animal fibres used for the production of a range of industrial and apparel textiles. Felting can be an adverse attribute as a consequence of dimensional shrinkage during laundering. As there is little objective information regarding the feltability of rare animal fibres or the factors which may affect felting three investigations were undertaken. A survey (n = 114) of the feltability of cashmere from different origins of production, cashgora, quivet, camel hair, llama, guanaco, bison wool, cow fibre and yak wool quantified the large variation between and within these fibre types. Cashmere from some origins and cashgora produced higher feltball density than the other fibres. Different nutritional management of cashmere goats (n = 35) showed that cashmere grown by poorly fed goats had a lower propensity to felt compared with cashmere grown by better fed goats. A consequence of the progressive blending of cashmere (n = 27) with a low propensity to felt superfine wool (high fibre curvature) increased the propensity of the blend to felt, but when the same cashmere was blended with low curvature superfine wool, there was little or no effect on feltability. The mechanisms which lead to variance in feltability of these fibres were quantified with multiple regression modelling. The mechanisms were similar to those reported for wools, namely variations in the resistance to compression, fibre curvature and mean fibre diameter, with likely effects of fibre crimp form. It is possible to source cashmere and other animal fibres which have different propensities to felt and therefore to produce textiles which are likely to have different textile properties.

Indices for cashmere fleece competition and across farm comparisons: The role of staple length in identifying goats of higher cashmere production

A single focus on mean fibre diameter (MFD, μm) as the definition of cashmere quality overlooks the effects of fibre length, softness and fibre curvature on cashmere processing, textile quality and consumer acceptance. Many farmers overlook the importance of cashmere staple length (SL, cm) in their fleece assessments. We aimed to determine the importance of SL in comparison with MFD when evaluating cashmere production and to identify how across farm comparisons of cashmere fleeces can be objectively undertaken. A sample of 1244 commercial cashmere fleeces from goats originating from many Australian farms was used. Least squares models, relating the logarithm of clean cashmere production (CCMwt, g) to MFD and SL, were fitted. Six years of data from the Australian cashmere industry between farm fleece competitions were analysed to determine the relation between CCMwt and MFD. In the research flocks, adjusting CCMwt of individual goats across farms for MFD only accounted for 2% of the variance, whereas SL accounted for 39% of the variance. The least squares additive model involving only SL was: log10(CCMwt)=1.570+0.06010×SL. Thus CCMwt was proportional to: 100.06010×SL=1.1484SL. It was appropriate to adjust CCMwt for SL by a factor 1/1.1484(SL-SL0) where SL0 is a standard SL of 7.5cm. The between farm index for cashmere weight equals: cleancashmerestaplelengthindex=2.823×CCMwt/1.1484SL. For industry fleece competitions, regression analysis indicated that there was no association between cashmere production and MFD (P=0.81), similar to the research data. Adjusting CCMwt for MFD in across farm comparison and fleece competitions appears to be ineffective. For farm comparisons and in fleece competitions it is important to assess cashmere SL. The use of the Clean Cashmere Staple Length Index will provide a more robust comparison of cashmere productivity between farms as it is an indirect indicator of desirable skin secondary follicle development. The results have application in development projects where obtaining a cashmere MFD test is costly or unavailable. © 2013 Elsevier B.V.

The influence of yarn parameters on the ultraviolet protection of yarns

 Improving ultraviolet (UV) protection of textiles is essential to protect wearers against UV radiation induced risks. In addition to fabric parameters, yarn parameters are important factors affecting UV protection of textiles. This work is to examine the influence of yarn parameters on UV protection in order to set up a statistical model for predicting the UV protection of yarns. Wool yarns with different variables were used to test the ultraviolet protection factor (UPF) values for data analysis and the model verification. The model provides the optimized parameters for the UV protective fabric design. This work is helpful as a pre-cursor to the development of a more advanced optical model, which will look at understanding the penetration of UV light through fibres, yarns and fabrics.

Lessons from silkworm cocoons for future protective materials design

 Evolved over millions of years’ natural selection, very thin and lightweight wild silkworm cocoons can protect silkworms from environmental hazards and physical attacks from predators while supporting their metabolic activity. The knowledge of structure-property-function relationship of multi-layered composite silk cocoon shells gives insight into the design of next-generation protection materials. The mechanical and thermal insulation properties of both domestic (Bombyx mori, or B. moriand Samia. cynthia, or S. cynthia) and wild (Antheraea pernyi and Antheraea mylitta, or A. pernyi and A. mylitta) silkworm cocoons were investigated. The research findings are of relevance to the bio-inspired design of new protective materials and structures.
The 180 degree peel tests and needle penetration tests were used for examining the peel resistance and needle penetration resistance of both domestic and wild silkworm cocoon walls. The temperatures inside and outside of the whole silkworm cocoons under warm, cold and windy conditions were monitored for investigating the cocoon’s thermal insulation function. Computational fluid dynamics (CFD) models were created to simulate the heat transfer through the A. pernyi cocoon wall.
The wild cocoons experienced much higher peeling peak loads than the domestic cocoon. This transfers to a maximum work-of-fracture (WOF) of about 1000 J/m2 from the A. pernyi outer layer, which was 10 times of the B. mori cocoon. The A. pernyi wild cocoon exhibited a maximum penetration force (11 N) that is 70 % higher than a woven aramid fabric. Silk sericin is shown to play a critical role in providing needle penetration resistance of the non-woven composite cocoon structure by restricting the relative motion of fibres, which prevents the sharp tip of the needle from pushing aside fibres and penetrating between them. The wild A. pernyi cocoon exhibits superior thermal buffer over the domestic B. mori cocoon. The unique structure of the A. pernyi cocoon wall with mineral crystals deposited on the cocoon outer surface, can prohibit most of the air from flowing inside of the cocoon structure, which shows strong wind resistance under windy conditions.

Relationships between sleeve trial and wearer trial assessment of discomfort and objective measurements

The relationships were investigated between the prickle discomfort scores, assessed by human response from wearer trial garment assessment, and sleeve trial, Wool ComfortMeter (WCM) and Wool HandleMeter (WHM) assessments of fabrics, and fiber diameter characteristics including mean fiber diameter (MFD). Sleeve trial assessment followed exercise, the use of a control sleeve to reduce participant variance and four sensory traits. WHM provides eight handle parameters calibrated against a panel of experts. Four scenarios were evaluated: sleeve trial assessment with MFD; sleeve trial assessment with MFD and WCM; sleeve trial assessment with MFD, WCM and WHM parameters; and sleeve trial assessment with WCM and WHM parameters. Data were analyzed using correlation and forward stepwise general linear modeling. There was no evidence that the incidence of fibers coarser than 30 µm aided the prediction of prickle discomfort once MFD had been accounted for in the models. There were significant correlations between the WCM measurement and each sleeve trial attribute. There was no significant correlation between WHM parameters and sleeve trial assessments. The sleeve trial attribute of ‘skin feel’ offers potential to improve the predictions made of wearer trial prickle discomfort when used in association of the WCM with or without data on fabric MFD. There was little evidence to support using WHM parameters with or without the WCM in predicting wearer assessed prickle discomfort of fabrics. These results indicate that the rapid evaluation of fabrics using sleeve trial assessment can provide cost effective ranking of consumer preferences.

Core-spun carbon nanotube yarn supercapacitors for wearable electronic textiles

Linear (fiber or yarn) supercapacitors have demonstrated remarkable cyclic electrochemical performance as power source for wearable electronic textiles. The challenges are, first, to scale up the linear supercapacitors to a length that is suitable for textile manufacturing while their electrochemical performance is maintained or preferably further improved and, second, to develop practical, continuous production technology for these linear supercapacitors. Here, we present a core/sheath structured carbon nanotube yarn architecture and a method for one-step continuous spinning of the core/sheath yarn that can be made into long linear supercapacitors. In the core/sheath structured yarn, the carbon nanotubes form a thin surface layer around a highly conductive metal filament core, which serves as current collector so that charges produced on the active materials along the length of the supercapacitor are transported efficiently, resulting in significant improvement in electrochemical performance and scale up of the supercapacitor length. The long, strong, and flexible threadlike supercapacitor is suitable for production of large-size fabrics for wearable electronic applications.

Review on fabrication and applications of ultrafine particles from animal protein fibres

Protein fibre wastes from animal hairs, feathers and insect secreted filaments can be aptly utilized by converting them into ultra-fine particles. Particles from animal protein fibres present large surface-to-weight ratio and significantly enhanced surface reactivity, that have opened up novel applications in both textile and non-textile fields. This review article summarizes the state-of-the-art routes to fabricate ultrafine particles from animal protein fibres, including direct route of mechanical milling of fibres and indirect route from fibre proteins. Ongoing research trends in novel applications of protein fibre particles in various fields, such as biomedical science, environmental protection and composite structures are presented. © 2014 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Silk films as a repair material for perforations of the tympanic membrane

Large, chronic perforations of the tympanic membrane or eardrum can cause hearing loss as well as a range of secondary health problems. Current methods of repair usually involve grafting a material such as cartilage from another site on the body across the perforation. However, given problems such as possible infections at the graft donor site and the inability to see through the graft to assess infection within the middle ear, there is a need to develop an alternative material that is strong, readily available and transparent. Such a material would allow for less invasive surgery and potentially result in a superior hearing outcome for the patient. Our recent work has identified silk fibroin films as a promising material for this application. This paper reviews the repair of large perforations and compares the mechanical properties of silk with some existing graft materials. It also briefly discusses the difficulties in defining and comparing these properties with such different materials.

Physical properties of novel co-woven-knitted fabrics

 Co-woven-knitted (CWK) fabrics have been reported previously. Historically these unique structures have been used to develop composite and shielding fabrics. In this study, novel CWK structures with unique appearances was developed with a modified machine using wool and polyester yarns. The physical properties of these fabrics were compared with conventional woven and knitted fabrics. The thickness of the CWK fabrics was similar to knits. The fabrics showed a unique tensile strength, with higher bending rigidity, and performed better in abrasion resistance.

Comparison between nanofiltration and forward osmosis in the treatment of dye solutions

Colour removal and the flux behaviour of nanofiltration (NF-DOW FILMTEC-NF245) and forward osmosis (FO-a flat sheet cellulose triacetate membrane with a woven embedded backing support) membranes were investigated in this study. The NF membrane was employed to perform dye removal experiments with aqueous solutions containing 15 g/L of NaCl and different concentrations of Acid Green 25, Remazol Brilliant Orange FR and Remazol Blue BR dyes. The increase in dye concentration resulted in a decline in water permeability and an increase in colour removal. When the concentrations of dye solutions varied from 250 to 1000 mg/L, at 0.8 bar of trans-membrane pressure, the NF system exhibited a steady permeate flux of more 30 L/m2h and a colour removal of more than 99%; salt rejection was more than 20.0%. Furthermore, the FO system possessed high dye rejection efficiency (almost 100%), with low permeate flux of around 2.0 L/m2h, when using dye solutions as feed streams and seawater as draw stream. The mode of operation (either FO or pressure retarded osmosis (PRO) did not change the flux significantly but PRO mode always produced higher fluxes than FO mode under the operating conditions used in this study. While both NF and FO can be used to reduce the volume of effluent containing dyes from textile industries, the energy spent in NF on applied pressure can be substituted by the osmotic pressure of draw solution in FO when concentrated draw solutions such as sea water or reverse osmosis concentrate are readily available.

Recent insights into microbial catalases: isolation, production and purification

Catalase, an oxidoreductase enzyme, works as a detoxification system inside living cells against reactive oxygen species formed as a by-product of different metabolic reactions. The enzyme is found in a wide range of aerobic and anaerobic organisms. Catalase has also been employed in various analytical and diagnostic methods in the form of biosensors and biomarkers in addition to its other applications in textile, paper, food and pharmaceutical industries. New applications for catalases are constantly emerging thanks to their high turnover rate, distinct evolutionary origin, relatively simple and well-defined reaction mechanisms. The following review provides comprehensive information on isolation, production and purification of catalases with different techniques from various microbial sources along with their types, structure, mechanism of action and applications.

High-performance multifunctional graphene yarns: toward wearable all-carbon energy storage textiles

The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young's modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m(-1)) and exceptionally high specific surface area (2605 m(2) g(-1) before reduction and 2210 m(2) g(-1) after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g(-1) at 1 A g(-1)) and rate capability (56 F g(-1) at 100 A g(-1)) while maintaining their strong flexible nature.

Fabric handle properties of superfine wool fabrics with different fibre curvature, cashmere content and knitting tightness

The handle properties of single jersey fabrics composed of superfine wools (17 μm) of different fibre curvature (114 vs. 74 °/mm) in blends with cashmere (fibre curvature 49 °/mm) were investigated. There were four blend ratios of cashmere (0, 25, 50, 75%) plus 100% cashmere. Each of the nine fibre blend combinations were replicated three times, and each was knitted into three tightness factors. The 81 fabrics were evaluated using the Wool HandleMeter, which measures seven primary handle attributes and Overall handle, and have been calibrated using a panel of experts and a wide variety of commercial fabrics. Results were analysed by ANOVA and general linear modelling. Tightness factor significantly affected all Wool HandleMeter attribute values, with the effect of tightness factor varying according to handle attribute. The Wool HandleMeter was able to detect differences between fabrics composed of superfine wool differing in fibre curvature, with lower fibre curvature wool fabrics having more preferred Overall handle and softer, looser, cooler, lighter and less dry handle attributes at some or all tightness factors compared with fabrics composed of higher fibre curvature superfine wool. Progressively blending cashmere with wool significantly improved Overall handle, increased soft and smooth handle, reduced dry, heavy and tight handle. Linear regression modelling indicated that fabric mass per unit area explained more than 50% of the variance in overall fabric handle and in combination with variations in fabric thickness and yarn elongation could explain 71% of the variance in Overall handle.