One promising application of polyurethane is artificial skin for medical training simulators, such as those used for suturing and injection practice. However, many medical simulators are disposable because they cannot self-repair wounds or needle holes. Incorporating self-healing capability into artificial skin would enable repeated use. In this study, two types of self-healing polyurethanes were synthesized to self-heal at room temperature via a hydrogen-bonding mechanism using isophorone diisocyanate (IPDI): IP-PU-1, which is covalently cross-linked, and IP-PU-2, in which part of the triol in the soft segment was replaced with a diol. ATR-FT-IR measurements and evaluations of mechanical and self-healing properties showed that IP-PU-1 exhibited better self-healing performance and a greater abundance of hydrogen bonded carbonyl groups (C=O) than IP-PU-2. Subsequently, injection type simulators (hereafter "injection models") were developed using both polyurethane based artificial skins, and leak tests were performed to evaluate healing performance. The pressure resistance of punctured and healed samples exceeded typical human blood pressure, indicating adequate reusability. Considering reusability, IP-PU-1 demonstrated better performance than IP-PU-2. Although IPDI based polyurethanes are known to exhibit excellent self-healing properties, their application to medical simulators has not yet been explored. By evaluating reusability from the perspective of molecular structure and incorporating self-healing functionality into the polymer design, this study demonstrates the feasibility of reusable medical simulators. This approach enables a new class of reusable training simulators and may further extend to broader softmaterial applications, including robotic skin.
Nylon is a petroleum-derived synthetic polyamide that exhibits excellent strength, flexibility, and durability; however, it is highly resistant to both chemical and biological degradation, which leads to its longterm persistence in the environment and imposes a significant environmental burden. Although nylon is widely used as a fiber in clothing and various other applications, it is frequently blended with other types of fibers. Practical and widely applicable technologies for selectively separating such composite materials have not yet been established. Because recycling is not feasible in their mixed state, these materials have conventionally been disposed of as waste. Therefore, the development of effective separation technologies is essential to enable the recycling of nylon-containing products. In this study, we targeted composite textiles composed of nylon blended with polyester, wool, or cotton and aimed to establish a process for the separation and depolymerization of nylon. First, high-molecular-weight nylon was selectively extracted from the composites using nylon-specific solvents, namely formic acid and 2,2,2-trifluoroethanol (TFE). The isolated nylon was then subjected to a biological monomer recycling (BMR) process that combines chemical conversion into water-soluble oligomers via hydrochloric acid treatment with subsequent enzymatic monomerization using a previously developed series of nylon-hydrolyzing enzymes (Nyl series). Each step was successfully achieved, enabling efficient conversion of nylon into its monomeric products. This method was applicable to all three types of composite textiles examined. Furthermore, to reduce the number of processing steps, we investigated direct heating of the composite materials in hydrochloric acid without prior separation. Although this approach was applicable only to polyester-nylon composites, it enabled single-step selective separation and conversion of nylon into water-soluble oligomers. This study provides a process-oriented framework for designing selective and efficient chemo-enzymatic recycling routes for nylon-containing composite materials.
This study reports a cost-effective and scalable strategy for fabricating silver-coated copper (Ag/Cu) powders intended for conductive-textile applications. By optimising pre-treatment, mechanical polishing and electroless silver-plating parameters, the Ag/Cu powders achieved a remarkably low resistivity of 1.8 x 10 Om and excellent adhesion to a range of textile substrates. The formulated conductive ink, based on Ag/Cu powders and a flexible resin binder, performed reliably on both natural and synthetic fibres. Wash testing (AATCC 135) showed that the sheet resistance rose from 2.0 Q sq 1to 3.2 Q sq 1 -about a 60 % increase-after 30 domestic cycles, yet remained well below the 5 Q sq 1limit typically required for textile sensors, confirming durable conductivity under laundering. These results highlight Ag/Cu-based fibre composites as a practical, lower-cost alternative to silver-only inks for flexible and wearable electronic systems.
While conventional linear semiconducting polymers generally possess terminal groups that lead to spatial and dynamical heterogeneity inappropriate in charge transporting process, it is considered that cyclic oligomers have several advantages as charge transporters due to the well-defined molecular structure without end groups and homogeneous electron distribution in frontier orbitals. Here, we prepared 4-octyltriphenylamine (OTPA)-based cyclic oligomeric mixture (m-COTPA) consisting of 5, 6, and 7-mers and a linear polymeric analogue (POTPA) via a one-pot reaction. Optical analyses revealed that POTPA exhibited slightly red-shifted absorption maximum, broader absorption profile and smaller Stokes shift compared with m-COTPA. Space-charge-limited current measurements demonstrated that m-COTPA exhibited superior hole mobility compared to POTPA. A perovskite solar cell utilizing m-COTPA as hole transporting layer achieved a power conversion efficiency of 10.60%, significantly outperforming POTPA-based device (7.67%). Cyclic oligomers are promising candidates for developing high-performance organic semiconducting materials even without time-consuming isolation into each oligomer.
The textile industry's quality control has traditionally relied on manual visual inspection, a laborintensive process prone to human error. This process constitutes a typical "vigilance task," where sustained attention over long periods often leads to a decline in detection performance, known as the vigilance decrement, due to high cognitive load. To address these human-centric challenges, this paper proposes a Human-in-the-Loop (HITL) automated fabric inspection system designed not to replace, but to augment the capabilities of skilled inspectors. The system was implemented as a "brownfield" retrofit, upgrading an existing inspection machine with a low-cost, non-invasive hardware and software package. At its core, a RealTime Models for object Detection (RTMDet) model is utilized to perform the primary, high-load vigilance task of defect scanning. This allows the human operator to focus on the higher-value task of verifying and classifying potential defects identified by the AI. A case study conducted in a real-world jeans manufacturing factory demonstrated that this HITL approach enhanced inspection task efficiency by approximately 2.5 times compared to traditional manual inspection, significantly reducing operator cognitive load and enabling parallel tasking. This study provides a practical blueprint for SMEs in the textile industry to implement effective, human-centric AI solutions within existing operational constraints.
The generation of fiber fragments (FF) from textiles through friction under daily-life has recently attracted attention due to their contribution to microplastic pollution. In this study, a long-term worn lab coat was examined using SEM to characterize location-specific frictional degradation. Distinct features were observed: fiber fracture and subdivision at corners and folds, surface degradation under surface-to-surface loading, and fiber twisting under multidirectional stresses. To reproduce these features, artificial rubbing tests were conducted using the Gakushin-type rubbing tester and Martindale tester. The Gakushin-type rubbing tester demonstrated the potential to reproduce characteristic degradation features in SEM images by adjusting the counterface and plastic bars. By contrast, the Martindale tester showed relatively low selectivity and versatility in degradation conditions, limiting the range of reproducible targets. These results suggest that frictional reproduction using the Gakushin-type rubbing tester provides a practical approach for evaluating FF generation and may contribute to the development of textile products with reduced environmental impact.
Understanding fiber-fiber interactions in materials using cellulose nanofibril (CNF) is essential for advancing bio-based material design. This study investigates the relationship between fiber network density and crosslinking points to estimate inter-fiber interactions in CNF sheets. The sheets were prepared from CNFs obtained from bacterial cellulose pellicle and bamboo pulp dispersions, subjected to various drying and solvent exchange conditions. Atomic force microscopy (AFM) images were processed and analyzed using SOAX software to quantify crosslinking points. Tensile tests were conducted to evaluate mechanical properties, and interaction energy per crosslinking point was calculated. The results showed that solvent exchange with ethanol increased the apparent number of crosslinking points but reduced the calculated interaction energy, suggesting weaker inter-fiber bonding. The estimated interaction energies ranged from values comparable to moderate hydrogen bonds to those dipole-dipole interactions, depending on the preparation methods. This approach provides a simple and effective method to estimate fiber-fiber interaction energy from network density and mechanical data, offering valuable insights for CNF-based material development.
Effect of water and organic solvents on dynamic viscoelasticity of cellulose triacetate fiber (CTA(f)) was studied comparing with that of regenerated cellulose fibers such as rayon, cupra and lyocell. The peak of the mechanical loss tangent (tan (sic): ratio of the storage modulus to loss modulus of viscoelastic materials) was observed during drying process of wet CTA(f) indicating that glass transition temperature of 193 degrees C in dry state decreased to room temperature in wet state. The same phenomenon has been observed for regenerated cellulose fibers; however, the height of the tan (sic) peak (tan (sic)(max).) for CTA(f) was lower than those of regenerated cellulose fibers. Tan (sic)(max) qualitatively indicates the size of the moving unit suggesting smaller size of the moving unit affected by water for CTA(f) than those of regenerated cellulose fibers despite quite low crystallnity of CTA(f). Organic solvents including both polar and nonpolar solvents induced glass transition for CTA(f). n-alkane with relatively large molecular weight, n-nonane and n-decane, also caused glass transition at room temperature for CTA(f) not for regenerated cellulose fibers.
