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1

Knitted Heating Mats

Pieklak Katarzyna, Mikołajczyk Zbigniew, Łopińska Julianna

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 6

39--50

EN

The paper deals with conceptual designs and research on flexible knitted heating mats differing in construction from textile heaters on low-elastic woven or nonwoven-foil substrates. Two variants of heating mats with elasticity from 100 to 300 % of relative elongation were designed and manufactured using knitting technology. The heating elements of the mats were parallel-connected sets of electrically conducted carbon threads and synthetic threads coated with silver. With considerable elongation in the range of 210÷270 % no damage was observed to the heating elements and resistance changes during the stretching process equaled from 0.015 to 0.22 Ω/% of elongation. The optimum power of the knitted heater in the range from 16 to 41 W, with high thermal efficiency for a 12 V supply voltage, was obtained thanks to proper density of the electrically conductive threads (resistors) and the appropriate structure of the knitted fabric. The surface temperature of the heater can be adjusted from 34 to 43 °C, which corresponds to human thermal comfort. One of the variants of the knitted heaters was applied in the construction of the seat and backrest of an office chair

2

Effect of Elasticity on Electrical Properties of Weft-Knitted Conductive Fabrics

Han Xiaoxue, Miao Xuhong, Chen Xi, Niu Li, Wan Ailan

Fibres & Textiles in Eastern Europe

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2021

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Vol. 29, no. 1 (145)

47--52

EN

Because of softness and lightness, various flexible sensors have attracted extensive attention and been widely studied. Sensing mechanism of most wearable sensors is derived from an elastic substrate, such as fabric or polymer materials. Although the mechanical-electrical performance of several flexible sensors has been reported, including sensitivity, linearity hysteresis and repeatability, research on the effects of substrate elasticity on sensor capacity is scarce. In this paper, the impact of spandex content, washing and ironing processing on the elasticity of weft knitted sensors was investigated by the constant- extension test method. Afterwards, differences in sensing properties between diverse elastic sensors under single as well as repeated stretch were reported. The experimental results showed that spandex content does influence the elasticity of knitted fabric, which has a further great effect on sensing properties. A highly elastic sensor is capable of detecting large-scale human motions, while sensors with lower elasticity are opposite, which demonstrates that elastic sensors can be designed and chosen to meet the requirements of detecting and monitoring distinct human motions.

PL

Ze względu na swoją delikatność i lekkość czujniki elastyczne przyciągają uwagę i są często stosowane. Często opisywane jest działanie mechaniczno-elektryczne kilku elastycznych czujników, w tym czułość, histereza liniowości i powtarzalność, badania nad wpływem elastyczności podłoża na pojemność czujnika są dość rzadkie. W pracy zbadano wpływ zawartości spandex’u, obróbki prania i prasowania na sprężystość dzianin wątkowych metodą badania stałego rozciągania. Następnie odnotowano różnice we właściwościach wykrywania między różnymi czujnikami sprężystymi przy pojedynczym i powtarzanym rozciągnięciu. Wyniki eksperymentalne wykazały, że zawartość spandex’u wpływa na elastyczność dzianiny, co dodatkowo ma duży wpływ na właściwości wyczuwalne. Wyniki pokazały, że wysoce elastyczny czujnik jest w stanie lepiej wykrywać ruchy człowieka, niż czujniki o niższej elastyczności, co pokazuje, że czujniki elastyczne można zaprojektować i wybrać tak, aby spełniały wymagania wykrywania i monitorowania różnych ruchów człowieka.

3

Influence of the Knitting Structure of Double-Layered Fabrics on the Heat Transfer Process

Bivainyte A., Mikučioniené D., Milašiene D.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 2 (91)

40-43

EN

Most of the studies carried out in this area have been devoted to measuring static thermal properties. Nevertheless, not only the amount of heat released to the environment is important but also the process of heat transmission over time. However, investigations in the field of the heat transfer process through knitted fabrics are very few, especially through double-layered weft knitted fabrics from a combination of natural or man-made yarns in one layer with synthetic thread. The main goal of this work was to investigate which structural parameter - the knitting pattern structure or raw composition of the knit - influences the heat transfer process through double-layered fabrics at a higher level. It was found that the structure of the knit highly influences the heat transfer process as distinct from the raw composition of knit.

PL

Większość badań dotyczących przepływu ciepła przez dzianiny dwuwarstwowe dotyczy warunków statycznych. W rzeczywistości ważnym jest nie tylko rozkład temperatury powstający w wyniku przepływu ciepła ale również zmiany zachodzące w czasie. W literaturze mało jest informacji na ten temat zwłaszcza dotyczących dzianin dwuwarstwowych, w szczególności zawierających kombinacje włókien naturalnych i chemicznych z polimerów naturalnych i syntetycznych. Celem pracy było stwierdzenie czy na przebieg temperatury w czasie bardziej oddziałuje struktura dzianiny czy rodzaj zastosowanych surowców. Stwierdzono, że decydujący wpływ ma struktura dzianin dwuwarstwowych.

4

Surface roughness measurement of weft knitted fabrics using image processing

Semnani D., Hasani H., Behtaj S., Ghorbani E.

Fibres & Textiles in Eastern Europe

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2011

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Vol. 19, no. 3 (86)

55-59

EN

This paper focuses on measuring the roughness of knitted fabrics using a non-contact method. Research on objectifying the handle of textile fabrics is a very important factor in textile and garment manufacturing and retailing industries. Fabric handle is influenced by mechanical and surface properties. The KES-F system is a standard objectified method among different measurement methods. However, the KES-F system is time-consuming, and the translation of the data measured is difficult. In addition, the KES-F method as a contact-method is more easily affected by environmental conditions, such as moisture, and is not suitable as an on-line system in the manufacturing process. Hence the surface roughness of knitted fabrics without any deformation was measured by a non-contact method using a high resolution scanner. The data was controlled on a computer by using MATLAB software to obtain the roughness index. The results were compared with the surface characteristic values (SMD) measured by the KES-F system. The findings show a good correlation between fabric roughness values measured by the two different methods. Moreover, a negative correlation coefficient shows that the roughness value measured by Kawabata changes reversely proportional to those measured by the image processing method. Finally, the non-contact measurement of fabric roughness using a high resolution scanner is useful for the description of fabric roughness.

PL

Omówiono bezkontaktową metodę pomiaru szorstkości powierzchni dzianin, bardzo ważnego czynnika zarówno dla produkcji dzianin i odzieży. Chwyt materiału uwarunkowany jest właściwościami powierzchni oraz parametrami mechanicznymi materiału. Powszechnie stosowaną metodą jest metoda KES-F, która jednakże jest metodą kontaktową podlegającą różnorodnym wpływom w tym wilgotności powietrza i nie nadaje się do stosowania on-line. Dodatkowo metoda jest czasochłonna a uzyskane wyniki trudne do interpretacji. Autorzy zastosowali metodę identyfikacji optycznej za pomocą skanera o dużej rozdzielczości, którego wyniki przetwarzano komputerowo stosując oprogramowanie MATLAB. Uzyskane wyniki porównano z wynikami otrzymanymi metodą KES-F. Otrzymano dużą korelację i stwierdzono praktyczną przydatność analizowanego systemu.

5

Pilling performance and abrasion characteristics of selected basic weft knitted fabrics

Akaydin M., Can Y.

Fibres & Textiles in Eastern Europe

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2010

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Vol. 18, no. 2 (79)

51--54

EN

The aim of this study was the determination of the effects of dyeing, knit construction and the thread yarn production type on the abrasion resistance and pilling performance of selected basic weft knitted fabrics. For this aim jersey and interlock fabrics were produced from 100% cotton ring and compact yarns. Some of the fabrics produced were dyed. The abrasion resistance and pilling performance of raw and dyed fabrics were measured. The results obtained were classified according to the knit construction, whether the fabric was raw or dyed, and the properties of the yarn from which the fabric was produced. According to the results obtained, the abrasion resistance and pilling performance of interlock fabrics were found to be higher than those of jersey fabrics, those of dyed fabrics higher than those of raw fabrics, and those of fabrics produced from compact yarns were higher than those fabrics produced from ring yarns.

PL

Celem pracy było określenie efektów barwienia, struktury dzianin i typu użytej do produkcji przędzy na odporność na ścieranie i pilingowanie wybranych dzianin rządkowych. W tym celu wyprodukowano dzianiny typu jersey i interlock ze 100% bawełnianych przędz rotorowych, kompaktowych. Część dzianin wybarwiono. Oceniano odporność na ścieranie oraz piling dzianin. Wyniki sklasyfikowano według struktury dzianin, barwienia i właściwości użytej przędzy. Na podstawie otrzymanych wyników stwierdzono, że odporność na ścieranie i pilingowanie dzianin interlockowych była wyższa niż dzianin typu jersey, a także dzianin barwionych niż surowych oraz tych wykonanych z przędzy kompaktowej niż standardowej.

6

Tribological properties of auxetic and conventional polypropylene weft knitted fabrics

Uzun M., Patel I.

Archives of Materials Science and Engineering

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2010

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Vol. 44, nr 2

120-125

EN

Purpose: The wear resistance and friction reducing properties of polymer fibres can be improved with negative Poisson's ratio behaviour. Poisson's ratio is defined as the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Large number of materials have positive Poisson's ratio, however there are some materials which exhibit negative Poisson's ratio, they are termed auxetic materials. Auxetic materials present unique property that they expand in all directions when they are stretched and contract when compressed. This paper has highlighted, compared and discussed the variation between the modelling, theoretical and practical differences of auxetic materials wear behaviour. Design/methodology/approach: For the purpose of this work, auxetic and conventional fibres were produced by the melt spinning mechanism using extruder. The fibres physical properties were evaluated such as Poisson's ratio, fibre count, elongation, force and tenacity. Mono-filament fibres were used for fabrication of weft knitted fabrics; plain (1x1) structure was employed for knitting fabric. The wear resistance of the knitted fabrics were tested by using Nu-Martindale Abrasion and Pilling Tester and comparison were made. Findings: The abrasive wear test results demonstrated that the auxetic based weft knitted fabrics have superior wear behaviour than the conventional fibre based weft knitted fabrics. Practical implications: The experiment showed that the auxetic material is capable of sustaining large amount of abrasion compared to conventional fabric. Originality/value: The paper compare and discusse the variation between the modelling, theoretical and practical differences of auxetic materials wear behaviour.