Reference Technology For New Achievements In Research On Increasing Heat Storage And Washable Textile Fabrics

The thermal storage and washability of polyester fabrics treated with tungsten bronze nanorods (TBNRs) were analyzed to determine the optimal concentration of photothermal effect. TBNRs with an average length of 34.0 ± 2.5 nm and a diameter of 2.3 ± 0.4 nm generate near infrared regions of TBNRs that can generate heat by effectively absorbing light through thermal decomposition of ammonium metatungstate (AMT) in oleamine (OA). The effects of TBNR concentration and silane coupling agent on the photothermal effect and washability of PET fabrics were evaluated by using a solar simulator. As a result, the photothermal effect was enhanced with the increase of TBNRs concentration, and showed the maximum photothermal effect at 5 wt%. In addition, the washing resistance is further improved by adding 0.5 wt% silane coupling agent. In general, post-processing effectively increased the photothermal effect, while the physical properties and color of polyester did not change significantly.

Introduction: Due to the recent spread of Covid-19, consumers began to spend more time in the natural environment while keeping a safe distance from each other. With the increase of outdoor activities, the demand for outdoor sports clothes also increases (Han, 2021). In addition, the rapid changes in climate and environment have fundamentally changed the way people dress (Bae, 2011), which has led to more interest in the thermal insulation of textiles. Therefore, fibers and fabrics with light weight, heat insulation and heat storage properties have been developed (Koo et al., 2007). The recently used thermal insulation method is to add various ceramics (Choe et al., 2006), but the thermal insulation ability of these fabrics in extreme environments is limited. Therefore, this study aims to improve the thermal insulation performance of polyester fabrics by treating fabrics with nano particles with photothermal properties (photothermal effect) in the outdoor environment.

Photothermal materials, including conductive, semiconductor and magnetic materials, such as tungsten bronze and graphene oxide, absorb energy and convert it into heat when irradiated by long wavelength near-infrared (NIR, 780-3000 nm) waves. The energy level of these materials is lower than that of ultraviolet or visible light; Therefore, they can absorb long wavelength near-infrared waves that are harmless to human body (Jeon et al., 2019). Tungsten trioxide (WO 3) is not suitable for NIR absorption; However, since alkali metal ions (M=Li+, Na+, K+, Cs+) are combined into the crystal structure of WO 3, a part of W 6+in the crystal is reduced to W 5+to form conduction bands. Subbands are created in the plasma region, forming local surface plasmon resonance (LSPR) and subband transitions. These enable the reduced WO 3 and MxWO 3 materials to strongly absorb NIR and release heat. (Park, 2020). Therefore, tungsten bronze nanoparticles doped with alkali metals such as tungsten trioxide have selective light absorption in the near-infrared region. This led to the synthesis of new compounds and various forms, including nanorods, nanowires and nanosheets (Lee et al., 2014). All people. (2019) studied ethylene propylene diene monomer (EPDM) nanocomposites by synthesizing tungsten bronze nanorods and nanoparticles coated with alkyl chains, and confirmed that the mechanical and photothermal properties were enhanced. Therefore, the research using nanoparticles is mainly carried out by mixing polymer materials, but this process involves the yarn or fabric stage rather than the textile manufacturing stage. Therefore, it is necessary to study a finishing method for fashion sensitive materials that need multi-step process. Therefore, a post-treatment process was developed to attach inorganic nanoparticles to the fiber surface.

Silane coupling agents contain inorganic reaction sites and can combine with most inorganic substrates (including glass, metal and silica), especially when the structure of the substrate contains elements such as silicon, aluminum and most heavy metals. If the coupling agent is condensed at the interface, a multi molecular structure of cross-linked siloxane will be generated on the surface of the inorganic material. When the silane coupling agent is connected to the surface of the inorganic material, the surface shows the surface chemistry or surface reaction characteristics of the organic groups connected to the silane coupling agent. The treated surface shows the surface energy of the above organic groups, which can be a reactive surface, determined by the reactivity of the organic functional groups in the silane coupling agent (Kutz, 2011). Therefore, coupling agents act as mediators, connecting organic and inorganic materials that are difficult to associate naturally (Song et al., 2011).

）A study was carried out to treat the fiber surface with silane coupling agent during the formation of the composite. The results showed that the interfacial shear strength and mechanical properties of the composite were improved. Buseher (2019) studied the thermal and mechanical properties of polystyrene composites using 3 - (trimethoxysilyl) propyl methacrylate (TMSPMA) as silane coupling agent, and proved that the composites treated with coupling agent have higher thermal stability. Therefore, silane coupling agent can realize the bonding of difficult bonding materials. In this study, TMSPMA was used to treat tungsten bronze nanorods (TBNRs) on the surface of polyester fabrics, and the physical properties of the resulting materials were evaluated.

With the demand for materials due to environmental changes, various materials with heat insulation and heating functions have been developed in various forms according to their applications (Lee&Song, 1994) There are many researches on photothermal materials; However, there is a lack of empirical research to analyze the changes in the physical properties of fibers after attaching photothermal materials to the fiber surface. In order to apply this technology to various materials and processes in the fabric stage, it is necessary to study the post finishing method of attaching functional materials to the outside of the fabric. In this study, tungsten bronze nanorods (a photothermal material) were attached to the polyester surface in different concentrations. In addition, TMSPMA is used in the polyester surface treatment process to improve the washing resistance of TBNR.

Method yu Material

Ammonium metatungstate hydrate (AMT), oleamine and 3 - (trimethoxysilyl) propyl methacrylate (TMSPMA) were purchased from Sigma – Aldrich. Sodium hydroxide (NaOH) is purchased from Samchun Chemical. Toluene and acetone were purchased from Dazhong Chemical. White 100% polyester fabric (microfiber) is purchased from Dou fabric.

Preparation of Tungsten Bronze Nanorods (TBNRs)

Add AMT (2.956 g), oleamine (160 mL) and NaOH (0.1584 g) to a three neck round bottom flask. After connecting the reflux condenser, thermometer and long needle to the flask, mix for 1 hour by injecting nitrogen to form nitrogen atmosphere in the flask. After 1 hour, heat the flask to 140 ° C, then gradually heat it to 250 ° C every 10 minutes. Heat the flask under stirring at 250 ° C for 8 hours, and keep the temperature below 250 ° C. After 8 hours, the reaction mixture was cooled to room temperature. Sediment was collected by centrifugation (8000 rpm, 3 times, 15 minutes each time). Treat with acetone to remove excess oleamine, and then dry at room temperature. When alkali metal ions (M=Li+, Na+, K+, Cs+) are used to reduce tungsten trioxide, the reduced WO 3 and M x WO 3 materials strongly absorb NIR and release heat (Park, 2020). Therefore, TBNRs are synthesized by thermal decomposition of AMT in OA.

Functional finishing with TBNR and silane

All microfiber PET samples have a size of 2 × 2 cm, weight 0.0271 g, thickness 0.12 mm, bath ratio set to 30:1. 1. 3, 5 and 10 wt% of fabric coating. 0.00813, 0.02439, 0.04065 and 0.0813 g TBNRs powder were respectively dissolved in toluene and stirred to prepare TBNRs. Replace the required dimension (2 × 2 cm) was immersed in the solution for about 1 hour. To coat the fabric with TBNR and silane, 0.04065 g TBNR powder and 0.00406 g silane were dissolved in 0.7684 g toluene, and then the required size (2 × 2 cm) of PET sheet in solution at 400 rpm for 1 hour. The concentrations of TBNRs and silane coupling agent were set at 5 and 0.5 wt% respectively. In the preliminary experiment, it was found that these two concentrations could produce the best photothermal effect. The coated fabric is dried at room temperature for one day, washed with distilled water at 40 ° C for 5 minutes, and conditioned at 21 ° C. The absorption rate of PET containing TBNRs was 3.32%, and that of PET containing TBNRs and silane was 4.06%.

Characterization: Use Gatan Microscopy Suite (Gatan Inc., Pleasanton, CA, USA) to analyze the TBNR size of images measured by FE-TEM (FEI Tecnai G2 F30 S-Twin). UV Vis absorption spectrum was obtained in the range of 300-2100 nm using UV Vis spectrometer (V-670, JASCO, Tokyo, Japan). In order to determine the influence of TBNR on the photothermal effect of polyester, the surface temperature changes after irradiation with a white light solar simulator (100 W, PEC-L01, Peccell Technologies Inc., Yokohama, Japan) were measured. L *, a *, b * and Δ The value of E is measured three times for each sample in the colorimeter (AMT507), and the elemental analysis of the sample is conducted by using a field emission scanning electron microscope with energy dispersive X- X-ray spectrometry (FE-SEM – EDX, JSM6701, JEOL, 1) In order to compare the tensile properties of the samples before and after finishing, according to the yarn stripping method (KS K 0520), the tensile strength tester is used to measure the tensile strength of the fabric in the warp direction. Through preparation, the size is 2.5 × 15 cm 2 rectangular polyester sample.

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Thermal storage and washability of tungsten bronze nanorods. pdf