During the production process of commercial carbon fiber reinforced polymers (CFRPs), a silane coupling agent is added to the carbon fiber at the sizing step as a binder to enhance the product’s physical properties. While improving strength, the silane coupling agent results in a silane residue on recovered carbon fibers (rCF) after recycling, which is a disadvantage when using recovered carbon fibers in the manufacture of new materials. In this study, the rCF is recovered from waste carbon fiber reinforced polymers (CFRPs) from the bicycle industry by a microwave pyrolysis method, applying a short reaction time and in an air atmosphere. Moreover, the rCF are investigated for their surface morphologies and the elements present on the surface. The silicon element content changes with pyrolysis temperature were 0.4, 0.9, and 0.2%, respectively, at 450, 550, and 650 °C. Additionally, at 950 °C, silicon content can be reduced to 0.1 ± 0.05%. The uniformity of microwave pyrolysis recycle treatment was compared with traditional furnace techniques used for bulk waste treatment by applying the same temperature regime. This work provides evidence that microwave pyrolysis can be used as an alternative method for the production of rCFs for reuse applications.
Disposing of carbon fiber-reinforced polymers (CFRPs) has become a pressing issue due to their increasing application across various industries. Previous work has focused on removing silane coupling agent residues on recovered carbon fibers via microwave pyrolysis, making them suitable for use in new materials. However, the mechanical performance and structural characteristics of these fibers have not been fully reported. This study investigates the time–temperature curves of CFRPs treated through microwave pyrolysis and analyzes the mechanical and structural properties of silane-controllable recovered carbon fibers. Additionally, emissions—including carbon monoxide, carbon dioxide, and particulate aerosols—were measured using handheld monitors and thermal desorption–gas chromatography/mass spectrometry to determine the composition of fugitive gases around the microwave pyrolysis system. The pyrolysis process at 950 °C, with an additional 1 h holding time, reduced the crystallite size from 0.297 Å to 0.222 Å, significantly enhancing tensile strength (3804 ± 713 MPa) and tensile modulus (200 ± 13 GPa). This study contributes to more sustainable CFRP waste treatment and highlights the potential for reusing high-quality carbon fibers in new applications, enhancing both environmental and worker safety.
Lithium-manganese oxide batteries are known for their long-term storage capabilities, characterized by low impedance and high discharge capacity. This study aims to enhance these properties by optimizing key battery components. XRD analysis of MnO2 (MD) powder, heat-treated at 400 °C for 5 hours, revealed improved discharge capacity. In addition, hot-pressed polypropylene nonwoven separators with electrolyte absorption exceeding 67 mg successfully reduced after-discharge impedance with minimal capacity loss (0.96%–1.26%). Last, the use of electrolyte additives led to a significant reduction in impedance for commercial electrolytes X and Y, contributing to overall battery performance improvement.
The conventional production of waterborne polyurethane (WPU) typically relies on organic solvents to regulate viscosity; additionally, traditional ionic WPU systems still utilize volatile neutralizers, raising environmental and health concerns. To overcome these limitations and reduce dependence on petrochemical resources, this study presents a solvent-free approach for WPU synthesis using isophorone diisocyanate (IPDI), polytetrahydrofuran (PTMG), and the nonionic PEG derivative YmerTM A-130. In addition, castor oil (CO), a renewable and hydroxyl-rich bio-based material, was incorporated as a partial substitute for PTMG to improve both sustainability and material performance. The effects of varying substitution ratios of castor oil on the physical properties of the resulting dispersions, dried films, and coatings were initially investigated. The results indicate that increasing the castor oil content from 0 wt% to 11.8 wt% led to an enhancement in tensile strength, rising from 1.45 MPa to 2.40 MPa. Concurrently, the temperature at 5% weight loss (Td5%) shifted upward from 263.84 °C to 285.36 °C, indicating a favorable trend in thermal stability. Furthermore, the preliminary solvent resistance, surface wetting characteristics, and environmental durability of the prepared coatings were evaluated and discussed.