In this study, we analyzed prefilter media and compared an original nonwoven filter and the media after postprocessing. Low melt fibers (LMFs) and polyphenylene sulfide fibers possessing chemical- and heat-resistant properties were used to develop the prefilter media. We analyzed the physical properties of the filter media and its performance, such as initial fractional efficiency, dust-retaining capacity, and arrestance. In particular, we investigated the effect of the post-drying process on the performance of the filter. Although there was no significant improvement in the filter performance, it is expected that bonding using LMFs or resin will enhance the physical properties of the filters to a greater extent than needle-punching processing where the fibers are mechanically bonded. The physical properties of the filter subjected to the post-drying process, such as tensile load and tear strength, were higher than those of the dough. Although filter media subjected to the post-drying process are less efficient, they are more durable and can be used for a long time. It is expected that including a post-drying process can reduce the energy consumption of the entire filtration system.

Strong acids, such as hydrochloric acid and sulfuric acid, are colorless and are not easily detected when leaked. Halochromic dyes can be used for detecting strong acids because they show different colors when exposed to acid liquids. In this study, methyl orange was used as a pH-indicating dye in detecting acid liquids. Nylon 66 woven fabric was dyed with methyl orange, and the dyeing properties were determined, along with the pH-sensing property, colorfastness, and fixing agent effect. Methyl orange in an aqueous solution showed maximum absorption at 464 nm with orange color at a pH of 5-10, whereas the maximum absorption changed to 507 nm showing red color at a pH of 2. Nylon 66 dyed with methyl orange exhibited a good color yield (K/S), and the dyeing property was influenced by the pH and dye concentration. When the dyed sample was immersed in a solution with a pH range of 3.5-4.0, its original orange color was maintained. Then, the color turned to reddish-orange when immersed in a solution of 2.0-3.0 pH and red in a pH 1.5 solution. The acid-sensing property was retained after fixing agent treatment. The wash and water fastness of the dyed fabrics varied from poor to very poor, and the fastness of the staining was improved to a moderate level by fixing agent treatment. The lightfastness indicators before and after the application of fixing agent treatment were moderate and good, respectively.

The aim of this study is to develop shock-absorbing materials for the knee area of wetsuits using fused deposition modeling (FDM) 3D printing technology. Four types of samples were prepared with 3D printing spacer fabrics using thermoplastic polyurethane filaments. The samples were named 3DSPF-2.5, 3DSPF-5.0, 3DSPF-7.5, and 3DSPF-10.0, corresponding to sample thicknesses of 2.5, 5.0, 7.5, and 10.0 mm, respectively. Tests were performed on the samples following DIN recommended guidelines to determine the tensile, ball rebound, and abrasion properties. The results of the tensile test showed that the initial modulus and load increased with sample thickness owing to the increase in the leg area and density of the spacer layer. However, 3DSPF-7.5 had the highest elongation among the samples. In addition, the samples in the cross direction (CD) exhibited improved tensile properties compared to those in the machine direction. From the results of the ball rebound test, the resilience of the samples increased according to the following sequence: 3DSPF-2.5 < 3DSPF-5.0 < 3DSPF-7.5 < 3DSPF-10.0. In the case of abrasion resistance, mass loss followed the order of 3DSPF-10.0 < 3DSPF-7.5 < 3DSPF-5.0 < 3DSPF-2.5. Therefore, it was demonstrated that 3DSPF-10.0 in CD possessed excellent strength, resilience, and abrasion-resistance properties. However, considering the ease of movement after wearing the wetsuit, 3DSPF-7.5 in CD, which exhibited the highest elongation, was confirmed to be the most suitable material for producing 3D printed spacer fabric structures for shock absorption in the knee area.

Because nonwoven fabrics can significantly attenuate acoustic energy through their high porosity and small fiber diameter, they have been widely used as sound-absorbing materials in various industries. Along with microfiber nonwoven fabrics, novel nanofiber nonwoven fabrics possess excellent sound absorption properties owing to their fineness. In this study, the sound absorption characteristics of composite materials composed of microwebs and nanowebs were carefully investigated using a stacking structure and the number of layers.

In this study, the physical properties and skin-health functions of nonwoven cosmetics treated with microcapsules containing citrus-flavored horse oil (CFHO) were investigated to determine the effects of treatment conditions, such as microcapsule diameter and bath concentration. From the results, a large diameter was found to have less influence on the mechanical properties, as it contributed to the lower stiffness and smoothness of the treated nonwoven material. Even though both microcapsule concentration and diameter influenced the released quantity of CFHO, diameter had a more significant effect on CFHO release. The CFHO-contained microcapsules appeared to generate excellent antimicrobial activities in the treated nonwoven cosmetics when the concentrations exceeded 250%. In vivo test results showed that large microcapsule diameters increased the quantity of skin sebum. The findings of this study could be applied in the development of dermally functional nonwoven cosmetic products.

Electrochromism is a phenomenon in which the color of an electroactive material changes when a voltage is applied. Polyaromatic hydrocarbons (PAHs) are colorless in the neutral state owing to their broad bandgap; however, under the applied voltage, they exhibit various colors during oxidation or reduction owing to the molecular plasma resonance phenomena. Among PAH materials, picene is an intriguing material, which has not been employed as an electrochromic material because of its high stability with a bandgap of more than 3 eV. In this study, the electrochromic performance of a picene-containing ion gel consisting of poly(vinylidene-co-hexafluoropropylene) and imidazole-based ionic liquid (IL) was investigated. In an electrochromic device (ECD) fabricated on indium tin oxide (ITO) glass, the picene ECD was colorless in the neutral state; in the oxidation and reduction states, it showed reversible changes to yellow with an absorption peak at 520 nm. As the IL content increased, the bandgap decreased, and the switching behavior improved slightly. To further enhance the electrochromic performance, silver nanowires (AgNWs) were applied to the ITO electrodes. Compared with pristine ITO, the AgNW-based electrode exhibited significant improvement in optical contrast. Silver fabrics were used to produce highly flexible textile-based ECDs, which showed vivid and reversible electrochromic transitions under an applied voltage.

In this study, polyurethane-urea (PUU) co-polymers were synthesized using polyether-type polyol (PTMG) and isosorbide. A low-diameter carbon nanotube (TWCNT) nanocomposite was manufactured using the synthesized PUU as a matrix. The thermal, physical, and electrical properties of the manufactured PUU/TWCNT were studied. As the TWCNT content increased, the crystallization peak of the composite was shown to be constant, and the thermal decomposition temperature was confirmed to be lowered. The mechanical properties of the manufactured PUU films showed low tensile strength and elasticity as the TWCNT content increased. The electrical properties were determined by measuring the surface resistance of the manufactured film. The electrical conductivity of the composite was shown to decrease the surface resistance as the TWCNT content increased. Transmittance and transparency analysis also confirmed the manufacture of transparent films with transparent and haze-free optical properties. The analysis of film surfaces through scanning electron microscopy showed that the TWCNTs were evenly distributed within the polymer matrix.

Lithium-air (Li-air) batteries, which use oxygen as an active material for the positive electrode, have many advantages such as low weight, low pollution, and low cost compared with commercial batteries. In this study, post-treatments, such as acid and heat treatment, were conducted on carbon nanotube (CNT) films, which were fabricated via the direct spinning method, to change the surface properties of the CNT films. The post-treated CNT films were used as positive electrodes for Li-air batteries to investigate the effect of post-treatment on the performance of Li-air batteries. The raw CNT film showed a high capacity of 7000 mAh/g after 18 cycles. The acid-treated and heat-treated CNT films exhibited improved cycling performance compared with the raw CNT film. It is known that the performance of the Li-air battery is affected by the morphology and functional group of the CNT film electrode.