Advanced Composites and Hybrid Materials最新文献

Optical fiber sensors are widely utilized for their precision, stability, adjustable functionality, and minimal signal degradation. They excel in detecting diverse parameters, even in challenging situations where conventional sensors may falter. This study aims to create a novel optical fiber sensor capable of concurrently detecting both temperature and ultraviolet (UV) radiation. The sensor was fabricated using digital light processing 3D printing technique. The photocurable resin for 3D printing the optical fiber sensor was prepared by incorporating thermochromic powder and UV-sensitive powders into a polyethylene glycol diacrylate and hydroxyethyl methacrylate polymer blend for multi-material printing. The optical fibers were printed in two distinct orientations: horizontal and vertical. The optical characterization of these sensors was carried out by measuring transmission and reflection using customized measurement setups. The vertically oriented fibers exhibit more reflectivity, whereas the horizontally oriented fibers demonstrate higher transmission, owing to the layering phenomenon. The vertically oriented multi-material optical fibers exhibit significant variation in the transmission spectra, making them ideal for dual sensing. A notable change in the transmission percentage at 600 nm was observed at temperatures of 25℃, 35℃, and 45℃, reducing from 12.13 to 9.5%, 17.31 to 15.6%, and 19.62 to 17.98% upon exposure to UV radiation, respectively. The presence of UV radiation and temperature fluctuations can be easily distinguished by analyzing the change in spectra. The proposed optical fiber sensors provide a promising sensing platform for dual sensing applications where continuous monitoring of UV and temperature detection is required.

Lost circulation is a prevalent and intricate phenomenon in the domain of oil and gas drilling, which has resulted in significant economic losses for the global oil industry. Common gel lost circulation materials have been observed to exhibit deficiencies in temperature resistance and gel strength. In this study, a lignin-based plugging hydrogel (Lig-plugel) was prepared for lost circulation plugging using a simple method. The hydrogel employed the self-cross-linking mechanism of lignin in a high-temperature environment, which reduced the quantity of cross-linker, achieved the objective of regulating gelation time, and enhanced its mechanical properties. The maximum compressive strain of Lig-plugel synthesized at 200 °C with a 25 wt% cross-linker amount reached 76.83%, and the compressive strength and compressive toughness reached 1.85 MPa and 276.13 kJ/m³, respectively. Furthermore, Lig-plugel exhibits excellent heat resistance. It demonstrates minimal mass loss during thermal decomposition in high-temperature environments below 220 °C, which is sufficient for high-temperature applications. Additionally, the simulated plugging experiments indicate that Lig-plugel has an effective plugging effect and is adaptable. This study presents an environmentally friendly and sustainable solution to the lost circulation problem and has a broad application prospect in the field of oil and gas drilling.

Supercapacitors, as a novel type of energy storage device, have garnered significant attention due to their outstanding charging and discharging rates, high power density, and safe operation. Electrode materials, crucial components of supercapacitor devices, directly influence the electrochemical performance. Hollow carbon spheres (HCSs) have emerged as noteworthy candidates in energy storage and conversion, particularly in high-performance supercapacitors, owing to their well-defined morphology, uniform size (100 μm to 3 nm), low density, and extensive surface area (300–2221 m² g⁻¹). Substantial advancements have been achieved in developing advanced supercapacitor electrode materials incorporating hollow carbon sphere structures. This paper provides a comprehensive overview and discussion of the preparation of hollow spheres with controllable structure and morphology. Additionally, it explores various methods employed in recent years to enhance HCS, encompassing variations in doping elements and adjustments in content and composite types. The primary objective of this paper is to elucidate the application of HCS as electrode materials in supercapacitors and to serve as a reference for further research on HCS-based materials.

Effective radiative cooling is crucial for reducing undesirable energy consumption caused by thermoregulation technology. However, conventional passive coolers still suffer from challenges such as vulnerability to harsh service conditions and suboptimal radiative cooling performance without guidance from optical design. Metacoating based on photonic structure design and all-inorganic components can overcome these drawbacks. In this paper, we fabricate a metacoating for radiative cooling, incorporating zirconia submicrospheres (ZS) within a potassium silicate binder. ZS with optimal diameters of about 500 nm were synthesized to efficiently scatter sunlight. The metacoating has a solar absorption (α_s) of only 0.04 in the 0.25–2.5 µm range, and an infrared emittance (ε) of 0.91 in the 2.5–16.7 µm range. The low solar absorption is attributed to the high backscattering efficiency of ZS and their high-volume fraction, as confirmed by Mie scattering theory and Monte Carlo ray-tracing simulations, while the high emittance is driven by vibrational absorption from chemical bonds in ZS and potassium silicate. After proton and electron irradiation, the metacoating retains α_s below 0.083 and ε above 0.910, indicating excellent irradiation resistance. Our findings highlight that metacoating utilizing ZS with a large bandgap and suitable diameters holds significant potential for advancing space radiative cooling technologies.

Molybdenum disulfide (MoS₂) after the few-layer (FL) processing draws attention to its attractive characteristics, such as broadening interlayer spacing, increasing active sites, and promoting purity of the metallic phase. Notwithstanding, the poor stability and easy aggregation of FL-MoS₂ limit its potential for development in the field of electrochemistry. Herein, a nanocomposite between FL-MoS₂ and reduced graphene oxide (rGO) is successfully constructed via the one-pot hydrothermal method. Furthermore, the FL-MoS₂@rGO composite with a stable structure is obtained by regulating the amount of rGO. The excellent supercapacitor capacitances of FL-MoS₂ after building heterostructure composites with rGO are displayed, owing to the synergistic effects occurring in heterostructure. The optimal sample of FL-MoS₂@rGO-2 possesses a specific capacitance of 346.1 F g⁻¹ at 1 A g⁻¹ and a rate ability of 57.2%. Moreover, the capacitance of FL-MoS₂@rGO-2 remains 99.1% after 10,000 cyclic charges and discharges. More importantly, the theoretical calculations confirm the source of extra specific capacitance and raise conductivity in FL-MoS₂@rGO. Also, a FL-MoS₂@rGO-2//AC flexible asymmetric supercapacitor device is successfully fabricated, which presents the superior energy density and power density of 84.31 µWh cm⁻² at 700 µW cm⁻², and 51.42 µWh cm⁻² at 3500 µW cm⁻². This work verifies the potential of the heterostructure composite constructed by FL-MoS₂ in energy storage of electrochemical application.

Given the inevitable generation of electromagnetic radiation within electronic devices, accompanied by heat, and the detrimental effects of such radiation on the performance of precision instruments, the development of materials that integrate microwave absorption with thermal energy storage has become imperative. In this study, a novel polyimide/polypyrrole carbon nanotube (PI/PPy-CNTs) porous structure was fabricated using a template method, freeze-drying, and carbonization processes. Subsequently, polyethylene glycol (PEG) was encapsulated within this structure via vacuum impregnation to produce PI/PPy-CNTs@PEG phase change composites (PCPCCs). Multi-interface heterostructures are designed at the micro level to improve dielectric loss and thus enhance electromagnetic wave absorption (EWA) performance, and dense networks are constructed at the macro scale to improve thermal conductivity. The resulting sample exhibited a thermal conductivity of 0.72 W/(m·K), a photothermal conversion efficiency of 92.9%, an enthalpy value of 148.2 J/g, and a minimum reflection loss of − 42 dB. Compared to pure PEG, the thermal conductivity of the composite increased by a factor of 2.3. In conclusion, these multifunctional PCPCCs show significant potential for applications requiring integrated thermal management and advanced EWA performance.

The increased frequency of fire incidents around the globe has resulted in significant loss of life and property, underscoring the urgent need for advanced fire mitigation strategies. Current approaches largely focus on traditional passive flame retardants and fire alarm sensors. However, flame-retardant additives pose a limited functionality during the intensified fire propagation. Besides, the commercial alarm sensors are generally effective only after significant fire propagation has occurred. Thus, integrating early self-alarm capabilities with flame-retardant properties directly into materials emerges as a highly promising solution. This approach offers rapid-fire detection within a response time of less than 16 s and maintains a stable, effective alarm even under extreme temperatures or during active fires. This review summarizes recent research on smart retardant materials for fire alarm systems (SRM-FASs), which synergistically combine flame retardancy with real-time fire detection to enhance both early warning and sustained resistance. The working mechanism, preparation techniques, and characterization methods of SRM-FASs are discussed. Developing sensitive and reliable SRM-FASs depends on two key aspects: the use of conductive network and flame-retardant materials. The conductive network materials include graphene-based and inorganic-based options, while the flame-retardant aspects specifically refers to biomass materials. Key challenges associated with SRM-FASs are highlighted, and future perspectives and opportunities are proposed. This work aims to provide readers with a comprehensive understanding of SRM-FASs and guide the development of cutting-edge SRM-FASs in the future.

Finding a way to increase the amount of recycled waste tyres is a current global challenge. Among others, the production of ground tyre rubber (GTR) and its application in a new rubber compound looks as a perspective way. However, the compatibility of GTR and rubber matrix is limited, leading to insufficient properties of the new material. To improve them, it is suitable to activate the GTR prior to mixing. In this paper, GTR obtained by water jet process was activated with microwave irradiation (i) in a household oven at 400 W and 800 W for 1 and 3 min, and (ii) in an industrial device at 500 W, 1000 W, 1500 W and 1750 W for 1, 3 and 5 min. A total of 7% (w/w) of the irradiated GTR was incorporated into a carbon black-filled rubber compound based on styrene-butadiene rubber (SBR), natural rubber (NR) and butadiene rubber (BR), with a formulation for off-road tyre treads. Most compounds containing microwave-treated GTR showed comparable or better properties than the reference with untreated GTR (tensile strength, 14.9 MPa; elongation at break, 437%; modulus at 300% elongation, 8.97 MPa; hardness, 65.6 Shore A). The industrial microwave device offered better results and the possibility of use of higher variation in conditions than the home microwave oven.

Bi₂WO₆/BiOCl nanocomposites with three-dimensional core–shell structure were synthesized by a two-step hydrothermal method. The compounds were characterized by XRD, SEM, TEM, HR-TEM, EDX, SAED, XPS, PL, UV–Vis DRS, photoelectrochemical, and photodegradation experiments. The result showed that the catalytic activity of Bi₂WO₆/BiOCl nanocomposites was significantly better than that of Bi₂WO₆ and BiOCl. The effect of the amount of Bi₂WO₆ on the properties of the composite was studied. The result showed that the Bi₂WO₆/BiOCl with three-dimensional core–shell structure had the highest photocatalytic degradation efficiency for TNT, and the degradation rate reached 90% after 180 min of visible light irradiation. In the degradation process of TNT, the reaction rate of 4.5 Bi₂WO₆/BiOCl is the highest, which is 0.20057 min⁻¹. After 4 cycles, the degradation rate of TNT by 4.5 Bi₂WO₆/BiOCl remained at 80%. The free radical trapping experiments showed that the holes and superoxide anions played a major role in the photocatalytic degradation of TNT wastewater by 4.5 Bi₂WO₆/BiOCl. Based on the results of free radical trapping experiment, Mott-Schottky test, and ultraviolet–visible diffuse reflection spectroscopy, the reaction mechanism of enhancing photocatalytic activity was proposed.

Passive daytime radiative cooling (PDRC) can scatter sunlight and radiate Earth’s heat into outer space through the atmospheric window to achieve cooling without additional energy consumption. The PDRC is considered a novel strategy that has the potential to address both energy shortages and global warming simultaneously. Despite significant progresses in the field of PDRC devices, there are still challenges from PDRC materials, manufacturing techniques, testing methods, and technical standards. Most of the reported results are far from practical applications. At present, there is still a lack of comprehensive review covering the material selection and structural design for efficient PDRC, multifunctional integration, and their related applications, which is the purpose of this review. In this review, we introduced the basic principles and design guidelines of PDRC aiming to maximize the cooling power. Then, the research progress of various PDRC devices based on material selection and structural design is highlighted, especially focusing on multifunctionality and related integrated technologies. Additionally, we summarized the development and potential applications of PDRC devices in energy-saving buildings, personal thermal management, electronic device cooling, energy harvesting, and water collection. Finally, existing challenges and future developments for PDRC devices are discussed and proposed.