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Kaunas, Lithuania

Grineviciute D.,Lithuanian Textile Institute | Krauledas S.,Lithuanian Textile Institute | Gutauskas M.V.,Kaunas University of Technology
International Journal of Clothing Science and Technology | Year: 2012

Purpose: The purpose of this research is to perform instrumental comparison of hand parameters of knitted fabrics produced from different biodegradable fibres and to analyze peculiarities of hand parameters' extent influenced by fabric structure and chemical softening. Design/methodology/approach: The hand of five types of different biodegradable fabrics was evaluated. Experiments were performed using a method based on the principle of specimen biaxial punching deformation when a disc-shaped specimen is extracted through a round nozzle. The Influence of fabric weave (terry and plain jersey) and finishing (padding with the silicone softener "Belfasin SI") on the fabric hand was investigated. Findings: Investigations have shown that weave type and finishing significantly influenced fabric hand properties. It was also stated that even tenuous differences between fabric parameters could be obtained by one numeral value of complex hand rate Q. Practical implications: Experiments have shown that KTU-Griff-Tester is a simple, reliable instrumental device suitable to obtain quantitative information about fabric mechanical properties. Evaluation of finishing influence on a fabric hand could be precisely expressed by one parameter Q. Originality/value: In the present research quantitative evaluation of new fabrics from biodegradable fibres hand was performed. Comparison between new biodegradable and traditional cotton fabrics has shown that new biodegradable fibres which are generally used for underwear, sportswear and for medical application are characterized by soft hand, as a result a good affinity with skin. © Emerald Group Publishing Limited. Source

Barauskas R.,Kaunas University of Technology | Abraitiene A.,Lithuanian Textile Institute
Composite Structures | Year: 2013

A multi-scale finite element model for the simulation of medium velocity ballistic impact on non-crimped laminated composite fabric packages has been developed in LS-DYNA. The targets are soft fabric structures of non-crimped fibre plies bonded together by polymeric filling. The model of each fibre ply is divided into farther and nearer to impact zones. The farther zone is a macro-level model of orthotropic homogeneous membrane, and the nearer zone is a mezzo level structure composed of narrow aramid strips and polymeric gaskets. Shell elements are used for all the structural components of the fibre ply. The macro-level models employs the material properties determined on the base of the finite element analysis of the micro-cube representing a small fragment of the fibre bundle. At mezzo level the material properties are modified by using a mezzo-cube, which represents the narrow strip and gasket together. The convergence of the narrow strips model is demonstrated. Simultaneously with the combined macro-mezzo level model of a ply two different macro-level models are investigated. Good agreement among the results provided by different models has been established by proper adjustment of erosion strain parameter on the base of reference results obtained at mezzo level. © 2013 Elsevier Ltd. Source

Varnaite S.,Kaunas University of Technology | Varnaite S.,Lithuanian Textile Institute
Medziagotyra | Year: 2010

The aim of the research was to assess the possibility of textile fabrics with conductive yarns to attenuate the value of electrostatic field strength. Nine groups of fabrics with conductive yarns were manufactured in Lithuanian Textile Institute for the study. Each group consisted of five fabrics differing by the fiber content. The conductive yarns were inserted into the fabrics at different specified intervals (only in weft direction or in weft and warp directions forming the grid). The electrostatic field strength was measured during the experiment using ESM-100 apparatus (measuring range of electrostatic field strength: 0.1 V/m-100000 V/m). The electrostatic field strength of high voltage generating power supply was measured under fabrics with conductive yarns, with no conductive yarns and without any fabric. It was found that despite fibre content all tested fabrics decrease electrostatic field strength. Insertion of natural fibres into synthetic yarns decreases shielding effectiveness of the fabric. More conductive yarns and shorter are the distances between these yarns in the fabric, the better protection from electrostatic field is found. In order to have better shielding effectiveness; the porosity of the fabric should be as low as possible. Source

Gudeika D.,Kaunas University of Technology | Lygaitis R.,Kaunas University of Technology | Grazulevicius J.V.,Kaunas University of Technology | Kublickas R.H.,Kaunas University of Technology | And 2 more authors.
Chemija | Year: 2012

New dimeric naphthalene diimides were synthesized via condensation of 1,4,5,8-naphthalene- tetracarboxylic dianhydride with different aromatic amines such as 2-amino-4-tertamylphenol and 4-tert-butylcyclohexylamine as well as using linking agents such as hydrazine and p-phenylenediamine. The unsymmetrical imide synthesis approach was used to prepare intermediate derivatives. The structures of the compounds were characterized by means of 1H NMR, IR and mass spectrometry. The thermal behavior of the naphthalene diimides was investigated via differential scanning calorimetry. The studies showed that the compounds prepared are amorphous materials with glass transition temperatures from 132 °C to 266 °C. Optical properties of the synthesised naphthalene diimides in solution were studied by UV spectroscopy. All the compounds absorb electromagnetic radiation in the range of 200-400 nm. © lietuvos mokslu akademija, 2012. Source

Bekampiene P.,Kaunas University of Technology | Bekampiene P.,Lithuanian Textile Institute | Domskiene J.,Kaunas University of Technology | Sirvaitiene A.,Kaunas University of Technology
Medziagotyra | Year: 2011

In the fiber-reinforced composites industry together with the promotion of environmental friendly production, synthetic materials are attempted to be replaced by renewable, biodegradable and recyclable materials. The most important challenge is to improve strength and durability of these materials. Matrix that supports the fiber-reinforcement in composite generally is brittle and deformation causes fragmentation of the matrix. Pre-tension of reinforcement is a well-known method to increase tensile strength of woven material. The current study develops the idea to use pretension of woven fabric in order to improve quality and strength properties of the obtained composite. Natural (cotton fiber) and synthetic (glass fiber) woven fabrics were investigated. The pressure forming operation was carried out in order to study clamping imposed strain variation across the surface of woven fabric. The uniaxial tension test of singlelayer composite specimens with and without pre-tension was performed to study the effect of pre-tension on strength properties of composite. The results have shown that pre-tension imposed by clamping is an effective method to improve the quality of shaped composite parts (more smoothed contour is obtained) and to increase the strength properties of composite reinforced by woven natural fabric. After pre-tension the tensile strength at break increased in 12 % in warp direction, in 58 % in weft direction and in 39 % in bias direction. Source

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