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EN
The microencapsulation of PCMs involves enclosing them in thin and resilient polymer shells so that the physical state of this material can be changed from solid to liquid and back again within the shells. The utilization of microencapsulated PCMs in textile goods is advantageous since the encapsulation prevents PCM dispersion in the structure, reduces evaporation and reaction of PCMs with the outside environment, provides an increased heat-transfer area and a constant volume, and allows an easy application without affecting other textile properties and a normal fabric-care. In this paper the structural composition, preparation methods and characteristics of the microcapsules are discussed. Microencapsulation is a very time-consuming and complicated chemical process, running over several stages, making the microPCMs very expensive. In addition to microencapsulation of PCMs numerous attempts have been made to contain organic PCMs in certain macrostructures such as polymer matrices or porous materials (silica powder, perlite, expanded graphite). These containment structures are known as form-stable composite PCMs. The preparation and characterization of novel form-stable phase change material (PCM) is presented.
EN
Thermal regulating fiber was generally prepared by the composition of phase change materials (PCMs) and fiber-forming polymers. The property of PCMs that remains the temperature constant during energy exchange process can be used to keep the body temperature constant and provide apparels with comfortable feelings, if a suitable PCM is employed. In this paper three ways to prepare the thermal regulating fibers are described. The first way is the composite spinning, in which PCMs are mixed directly with polymer melts or solutions for spinning, thus the forming fibers with shell-core or "sea-island" structure. The second way is the hollow fiber filling, in which PCMs are filled into the hollow fibers to endow fibers with energy-storing ability. The third way is the microcapsule spinning in which the microcapsules containing PCMs are mixed with polymer melts or solutions for spinning. The advantages and disadvantages of these methods are discussed.
5
Content available remote Thermal manikin evaluation of PCM cooling vests
EN
To diminish a worker’s thermal discomfort in a moderately hot environment, a new microclimate cooling vest was designed and tested. The cooling vest was intended to be worn under a chemical protective garment. As coolants, encapsulated phase change materials in the form of macrocapsules of 3 mm diameter were used. The cooling effect is based on the latent heat absorption of phase change material; a highly-productive means of thermal storage. Two kinds of macrocapsules were selected: containing hexadecane (melting point 18 °C) and containing octadecane (melting point 28 °C). MacroPCMs were inserted into small knitted sacks, which were then adhered to the inner surface of the vest i.e. near the skin. Air gaps between the macroPCM particles facilitate both heat and moisture transport through the vest. The total weight of the cooling vest was 2.64 kg, the vest area comprising about 20% of the total body surface area. A stationary thermal manikin consisting of 16 electrically independent heating segments was used to evaluate the cooling effectiveness performance of the vests. Experiments were carried out in a climatic chamber where the air temperature was 20 °C, the relative humidity 50% RH, and the air velocity 0.4 m/s. The results of the experiments demonstrated that the vest containing a mixture of macrocapsules with hexadecane and macrocapsules with octadecane had the best cooling characteristic.
PL
W celu zmniejszenia dyskomfortu termicznego u pracowników wykonujących umiarkowany wysiłek (240 – 300 W) fizyczny w odzieży ochronnej, zaprojektowano i wykonano prototyp kamizelki chłodzącej zawierającej materiał przemiany fazowej (PCM) w formie makrokapsułek o średnicy 3 mm. W badaniach użyto dwóch rodzajów makrokapsułek: zawierających oktadekan (temperatura topnienia 28 °C) i zawierających heksadekan (temperatura topnienia 18 °C). PCM zawarty w makrokapsułkach pochłania ciepło generowane przez organizm użytkownika odzieży ochronnej i hamuje wzrost temperatury mikroklimatu pod odzieżą ochronną. Woreczki z dzianiny poliestrowej zawierające kapsułki z materiałem przemiany fazowej były przymocowane do wewnętrznej powierzchni kamizelek z tkaniny bawełnianej i znajdowały się w pobliżu skóry użytkownika odzieży. Luźna struktura dzianiny oraz szczeliny powietrzne między makrokapsułkami PCM ułatwiają transport zarówno wilgoci jak i ciepła przez kamizelkę. Masa kamizelki wynosi 2.64 kg, a pole jej powierzchni wynosi około 20 % całkowitego pola powierzchni organizmu użytkownika. Skuteczność chłodzenia kamizelek oceniano posługując się stacjonarnym 16-to elementowym manekinem termicznym Diana, o kształcie i wymiarach dorosłej kobiety. Pomiary prowadzono w komorze klimatycznej w warunkach opisanych w normie PN ISO 15831, tj. przy temperaturze powietrza 20 ± 1 °C i wilgotności względnej 50 ± 3% oraz średniej prędkości przepływu powietrza: 0.4 ± 0.1 m/s. Kamizelka chłodząca umieszczona była na manekinie pod jednoczęściowym kombinezonem chroniącym przed środkami chemicznymi. Na podstawie wyników tych badań można powiedzieć, że najkorzystniejszą charakterystykę chłodzenia ma kamizelka z czynnikiem chłodzącym w postaci mieszaniny makrokapsułek z oktadekanem i makrokapsułek z heksadekanem.
EN
This paper reports a study on the thermoregulation properties of PCM nonwovens. Microencapsulated n-alkanes (n-octadecane and n-eicosane) dispersed in a polymer binder (acrylic-butadiene copolymer) were applied to needled and hydroentangled nonwovens by the pad-mangle or screen printing method. The surface morphology and cross section of PCM nonwovens were observed by means of scanning electron microscopy (SEM). The thermal storage/release properties of the nonwoven samples treated with microPCMs were analysed by DSC, and the thermal resistance of the nonwovens under steady state conditions was determined by means of a sweating guarded hotplate instrument. The transient thermal performance of the nonwoven samples containing microPCMs was examined using novel apparatus with a dynamic heat source. The temperature regulating factor (TRF), defined by Hittle, was determined for selected cycle times of heat flux changes (t), the results of which are shown in diagrams presenting the relation TRF = f(t). The results obtained show that the main factor determining the TRF value is the amount of latent heat in a unit area of nonwoven fabric. Thermoregulating properties of the printed nonwoven sample with microPCMs are identified as being dependent on the position of the microPCMs layer. This work shows the possibility of achieving a significant thermoregulation effect even with moderate amounts of microPCMs incorporated at a proper location in the nonwoven system.
PL
Mikrokapsułki PCM (oktadekan i eikosan), zdyspergowane w środku wiążącym (kopolimer butadienowo-akrylowy), były aplikowane na włókniny igłowane techniką napawania i techniką druku sitowego. Następnie, posługując się stanowiskiem pomiarowym umożliwiającym badanie właściwości termicznych tekstyliów w warunkach dynamicznych, wyznaczano współczynnik termoregulacji termicznej (TRF) przygotowanych próbek włóknin. Współczynnik TRF, zdefiniowany przez Hittle’a był wyznaczany dla dla 6 wybranych okresów (t) zmian strumienia ciepła. Wyniki tych pomiarów przedstawiono w postaci krzywych obrazujących zależność TRF = f(t). Stwierdzono, że zasadniczym czynnikiem determinującym wartość współczynnika TRF jest ilość utajonego ciepła przemiany fazowej, zakumulowana przez jednostkę powierzchni materiału tekstylnego. W przypadku włóknin drukowanych, wartość TRF w znacznym stopniu zależy od położenia warstwy PCM względem źródła ciepła. Umieszczenie warstwy PCM w bezpośrednim sąsiedztwie źródła ciepła powoduje pogorszenie właściwości termoregulacyjnych układu. Uzyskane rezultaty wskazują na możliwość uzyskania znacznego efektu termoregulacyjnego, nawet przy umiarkowanych ilościach mikrokapsułek umieszczonych w odpowiednim położeniu w strukturze włóknistej.
EN
This review summarizes the key topics in the field of self-cleaning textiles. Hydrophobic and hydrophilic surfaces of textiles are discussed and the various mechanisms of self-cleaning are described. The recent research on modification of cotton fabrics surfaces by photocatalytic TiO2-coatings were discussed. The biomimetic approach for fabrication of superhydrophobic fibers with self-cleaning ability is presented.
EN
In recent years, one dimensional (1D) nanostructured materials such as nanorods, nanowires, nanotubes, nanowhiskers or nanofibers have been intensively studied owing to their potential technological applications in many areas including mechanics, electronics, optics, photonics, optoelectronics, catalysis, sensing, filtration, biotechnology and biomedicine. A large number of synthesis and fabrication methods have been developed for generating 1D nanostructures from various materials. This paper gives an overview of the techniques currently used in laboratory research such as drawing, template syntesis, phase separation and self assembly.
EN
A review of articles concerning functional, textile materials, presented on ITC&DC 2006 in Dubrovnik.
EN
In order to determine the improvement in thermal comfort resulting from the PCM application in clothing protecting against foul weather, controlled wearing trials in a climatic chamber have been performed. Loose fitted jackets made of waterproof breathable fabric were selected as experimental garments. Three different nonwovens containing microPCMs were inserted in the test jackets. The set of identical jackets but without microPCMs were tested. Four young healthy men participated in wear trials as test subjects for each clothing system and each ambient temperature, at periodically changed physical actvity. The wearing trials were conducted at an ambient temperature 0°C and -10°C and relatve humidity 25%. During the test skin temperatures at four sites (chest, back, arm and hand) were recorded. Additional information were derived by measuring the body mass loss. Subjective ratings of the thermal and overall comfort sensations were obtained during the experiment. The test results demonstrate that nonwavens containing microPCMs improve the clothing microclimate, which can lead to a greater feeling of comfort. The improvement of microclimate is proved by smaller change of the chest skin temperatures and lower amount of moisture generated by the skin. The results of measurements are supported by subjective statements about comfort. The study reveals that the ability of nonwoven containing PCM to buffer the heat is influenced by the ambient temperature.
EN
Part IV presented using liposomes for wool dyeing in a cost-effective and environmentally sensitive way. The properties of cyclodextrins and their applications in the processes of the textile industry is described.
EN
Part I presents a basic overview of the microencapsulation science. The encapsulation techniques, structure of microcapsules and their and properties, the fixation of microcapsules to textiles are discussed. Some recent applications of microencapsulation technology in textile finishing are highlighted. Examples of each technology are described.
EN
The part II is concerned with the control release of active substances such as antimicrobials, fragrances and dispersive dyes.
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