NEW TECHNIQUE FOR OPTIMISING YARN-END PREPARATION ON SPLICER, AND A METHOD FOR RATING THE QUALITY OF YARN-END
This paper presents a method for improving the yarn-end preparation on a splicer by forming a loop outside the opening tube which assures gentle delivery of the yarn to the opening tube, as well as control of the yarn-end length which will be prepared. Twelve groups of yarns were selected and tested using the new technique and a standard splicer. The new technique for yarn-end preparation showed better results in comparison to the standard splicer, especially for high twisted and plied yarn.
PREDICTIVE MODELS FOR STRENGTH OF SPUN YARNS: AN OVERVIEW
Over the past century or so, determining the predictive models of yarn strength has been the subject of a number of investigations, because yarn strength is a principle component of yarn quality. The aim of these models is to enable the yarn strength to be predicted from the properties of its component fibres as well as other parameters. The development of predictive modelling of yarn strength is always significant both in theory and in practice. In this article, a review of various predictive models of yarn strength is presented.
STUDIES ON STRUCTURE AND PROPERTIES OF NEPHILA-SPIDER SILK DRAGLINE
Spider dragline silk is an extremely strong biopolymer and has unique combination of desirable mechanical properties. In the present paper dragline of Golden Nephila spider was studied for dimensional, structural, physical and tensile properties. The test results established significant variability in diameter and denier of dragline filaments. The filaments possessed nearly circular cross-section and were found to be sensitive to moisture. The draglines exhibited super contraction in water. It has high strength and large elongation to break (45.9 cN/tex and 38.7 %, respectively). X-ray crystallinity of 17.5 % was obtained. The fibres were also subjected to thermo- mechanical and dynamic mechanical analysis.
MICROWAVE IRRADIATION TECHNIQUE TO ENHANCE PROTEIN FIBRE PROPERTIES
Microwave irradiation technique was used for the chemical modification and grafting of protein fibrous materials, such as domestic silk (Bombyx mori), tussah silk (Antheraea pernyi), and wool fibres. Epoxide compounds Denacol EX810 and EX313 reacted effectively with the protein substrates. As alkali catalysts, sodium hydroxide was more effective than sodium thiocyanate. The optimum concentration was 0.25 w%. Weight gain values up to 8% were attained with 10-15 min irradiation time at 200W power. Graft-copolymerisation of vinyl monomers onto protein fibres resulted in variable weight gains, depending on the kind of fibre, the grafting monomer used, and the concentration of the padding solution. For example, after grafting with iso-propyl methacrylate (IPMA), the weight gain of fibrous proteins took place in the following order: Bombyx mori silk > tussah silk > wool. Bombyx mori silk gained more weight with IPMA than with 2-hydroxyethyl methacrylate (HEMA) or methacrylamide (MAA). The weight gain of Bombyx mori silk with HEMA significantly increased when the initial monomer concentration was raised to 400% owf, reaching a maximum value of 40%. The tensile properties of the protein fibres grafted with IPMA, MAA, and HEMA remained unchanged or slightly improved compared to the reference fibres. Fibres modified with epoxides showed a drop in tensile performance. The surface morphology of fibres treated with epoxide compounds or graft-copolymerised with vinyl monomers was almost unaffected, with the exception of HEMA-grafted fibres, which showed the presence of homopolymer deposited onto the surface at a weight gain exceeding 20%.
DEVELOPING FIBROUS MULTIFUNCTIONAL STRUCTURES FOR TECHNICAL APPLICATIONS
This paper describes a quick prototyping unit for fibrous multifunctional structures which has been set-up at the University of Minho. This unit provides for fast development of technical samples for a variety of special applications, mainly in the areas of health and well-being, sports goods, personnel protection, techno-fashion, the civil construction and building industries, composite materials, and so on.
The unit works systematically through the areas of conceptualisation, design and simulation, development, manufacturing and testing of technical and intelligent textile materials and structures, providing solutions for technical problems.
New structures are developed for specific applications where special requirements are needed.
It provides the best solution in terms of materials, structures, technologies and cost. The technologies involved include advanced CAD systems, FEA (finite element analyses), testing of mechanical properties, permeability, conductivity, microscopy, as well as small-scale-computer controlled manufacturing of yarns, nonwovens, wovens, warp & weft knits, braids and hybrid structures. Special finishings and surface treatments, coating and lamination are also possible.
The unit is used for research, education and to provide services for companies in emerging markets for advanced textile materials. Examples of the novel products developed are provided.
STUDY OF THE ENZYME TREATMENTS EFFECT ON THE PILLING BEHAVIOUR OF KNITTED WOOL FABRICS
WATER RETENTION BY ACTIVE CARBON FIBRES OBTAINED FROM VISCOSE
ANALYSIS OF TRANSVERSE DEFORMABILITY OF SPACER PRODUCTS