Lithium-ion batteries (LIBs) have become a core technology for a wide range of energy-storage applications due to their high energy density and long cycle life. Within the electrode, the binder, which holds together the active materials, conductive additives, and current collector, plays a critical role in maintaining structural stability and ensuring stable electrochemical performance. However, conventional binders, such as poly (vinylidene fluoride) (PVDF) and water-based systems, are often unable to effectively accommodate the volume expansion or prevent interfacial degradation during repeated charge-discharge cycles. In this context, polyimide (PI) has emerged as a promising next-generation binder material owing to its excellent thermal and mechanical stability, as well as its tunable molecular structure enabled by diverse functional groups (e.g., -COOH, -NH2, -O-, -SO3H, -CF3). This review systematically examines PI binder synthesis strategies, structure-property relationships, and their applications in major electrode systems, including LFP, NCM, and Si-based anodes. In summary, polyimides are identified as high-performance multifunctional binders capable of stabilizing the electrode-electrolyte interface, enhancing ionic transport, and mitigating volume expansion. These structural design strategies provide important guidance for the development of next-generation high-energy-density LIBs.
Various wear particles generated on roads are dispersed by traffic, with repeated scattering caused by continuous vehicle movement. In contrast, road dust deposited on snowbanks remains immobilized, preventing further resuspension. In this study, road dust deposited on snow during winters and transferred from wet roads was collected to obtain samples transferred by single-step scattering. The tire wear particle (TWP) content was analyzed as a function of particle size. Rubber components were identified in samples smaller than 212 mu m : the styrene-butadiene rubber (SBR) content increased with decreasing particle size, whereas the natural rubber (NR) and butadiene rubber (BR) contents decreased. SBR was the predominant component in all samples, indicating that TWPs from passenger cars were more prevalent than those from buses or trucks. The TWP content ranged from 0.45% to 0.57%, which was lower than the values typically reported under dry road conditions.
This study investigates the chemical resistance of EPDM elastomer composites filled with silica of varying specific surface areas (SSA) when exposed to ammonia. The composites were immersed in 99.5% anhydrous liquid ammonia for 168 h, and changes in crosslinking density, volume, surface and fracture surface morphology, mechanical properties, and dynamic mechanical properties were evaluated before and after immersion. Exposure to ammonia resulted in an increase in crosslinking density, surface roughness, and glass transition temperature (Tg), along with decrease in volume and tan delta. The magnitude of these changes decreased with increasing silica SSA. Overall, EPDM composites containing higher-SSA silica exhibited improved stability in terms of crosslinking density, volume change, mechanical performance, surface characteristics, and dynamic mechanical behavior both before and after ammonia exposure. These findings demonstrate that silica SSA is a critical parameter in the design of EPDM-based seals and gaskets for use in 99.5% anhydrous liquid ammonia environments.
Rubber materials are extensively utilized in industrial applications because of their elasticity and ability to recover after deformation. However, vulcanized rubbers are prone to permanent deformation under thermal or mechanical stress due to variations in crosslink density. This study evaluated the recovery behavior of rubber-based composites blended with thermoplastic resins under circular deformation conditions. Six composite formulations were prepared by varying the plasticizer and vulcanization accelerator contents. The composites were processed via melt mixing and hot pressing, and rheometer measurements were performed to determine their crosslinking characteristics. Circular deformation tests were conducted at room temperature and at 80 degrees C to quantify their recovery performance after thermal aging. The 100% rubber vulcanizate exhibited the highest initial recovery (92.5%) and achieved full shape restoration within 8 h at room temperature. In contrast, thermoplastic-blended samples showed lower initial recoveries (78.7 similar to 86.2%) and delayed full recoveries up to 45 h. At 80 degrees C, all samples experienced residual strain, with the rubber-only sample recovering up to 93.7%, whereas blended samples ranged between 71.2% and 78.0% recovery. Notably, despite the reduced recovery performance, the thermoplastic blends exhibited enhanced mechanical strength and abrasion resistance. These results highlight the trade-off between thermal recovery and mechanical reinforcement when thermoplastics are incorporated. The insights gained from this study can be used to optimize the fabrication of thermoplastic-rubber composites for applications requiring tailored elastic and thermal-aging performance.
With t he global rise in plastic use, concerns over microplastics generated through weathering processes are intensifying. While many studies have examined the occurrence and impacts of microplastics, relatively few have systematically explored the weathering behavior of different plastic types. This review focuses on the mechanisms of weathering and associated property changes in representative plastics, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), with an emphasis on Raman and infrared (IR) spectroscopy. These nondestructive techniques enable the identification of chemical changes such as oxidation, carbonyl formation, and surface degradation. However, no standardized protocol currently exists for plastic-specific weathering assessments. Additionally, significant differences persist between artificially aged microplastics and those found in the environment, which are often associated with biofilms, organic matter, and pollutants. These discrepancies complicate the interpretation of environmental behavior and toxicity. Therefore, there is an urgent need for experimental models and analytical methods that better reflect real-world conditions and facilitate accurate cross-comparisons among plastic types. This review aims to support such efforts by summarizing current knowledge and identifying key gaps in microplastic weathering research.
