With the high-density integration and lightweight of electronic components, polyimide-based graphite film has attracted extensive attention due to its excellent thermal conductivity. In this study, 4,4,-diaminodiphenyl ether and trimthalic acid dianhydride were used as monomers for copolymerization, and calcium phosphate was used as a chemical imidification reagent. The effect of chemical imitization reagent addition on the properties of polyimide (PI) film was studied. The results show that the microscopic morphology of the PI film prepared by chemical imidization method is smoother, denser and orderly, with higher graphitization degree, larger grain size and smaller lattice defects. When the calcium phosphate addition is 0.1%, the tensile strength of PI film reaches 98.42 MPa and the thermal conductivity of graphite film can reach 1 623.9 W·m-1·K-1. In the process of simulating heat dissipation testing, the surface temperature of graphite film can be rapidly cooled from 60 ℃ to 24 ℃ in just 60 seconds, which has great potential for application in modern integrated advanced electronic components and high-end electronic products and other thermal management fields.
The liquid water generated during the operation of proton exchange membrane fuel cells (PEMFCs) is unable to be discharged on time, resulting in the blockage of pores and subsequently affecting the operational efficiency of the battery. Therefore, carbon paper for gas diffusion layer requires a drainage functionality. In this paper, carbon paper for gas diffusion layer was hydrophobized with polytetrafluoroethylene (PTFE) as a hydrophobic agent, with five different PTFE solutions of varying mass concentrations (5wt%, 10wt%, 15wt%, 20wt%, 25wt%). The structure and performance of the carbon paper were systematically characterized by SEM, porosity, through-plane (TP) permeability, contact angle, mechanical properties, and TP resistivity. The carbon paper was then assembled into single cells for performance testing. The results show that when the PTFE concentration increases from 5wt% to 25wt%, the TP permeability of the carbon paper decreases dramatically from 197.62 mL·mm/(cm2·h·Pa) to 102.07 mL·mm/(cm2·h·Pa), and the permeability performance of the carbon paper treated with 25wt% PTFE is decreased by 53.4% compared with the untreated carbon paper. With the increase of PTFE concentration, the contact angle of the carbon paper increases from 125° to 152°, and its hydrophobicity is significantly improved. The effect of PTFE concentration on the mechanical properties of the carbon paper is negligible, with only slight decreases in tensile strength and slight enhancements in bending resistance observed as the PTFE concentration increases. Under the same pressure (1 MPa), the TP resistivity of carbon paper becomes larger with the increase of PTFE concentration. And when the PTFE concentration is increased from 5wt% to 25wt%, the TP resistivity of carbon paper increases from 9.02 mΩ·cm2 to 15.8 mΩ·cm2, an increase of 75.15%. Notably, at a PTFE concentration of 10wt%, the single cell exhibits optimal performance, with a contact angle of 133°, the TP permeability of 181.80 mL·mm/(cm2·h·Pa), and the TP resistivity of 10.07 mΩ·cm2 under 1 MPa.
To improve the permeation separation performance of nanofiltration membranes, TA-MoS2 nanosheets prepared by liquid-phase ultrasonic exfoliation were introduced into the active layer of polyamide (PA) formed by polyethyleneimine (PEI) and homotrimethylene tricarbonyl chloride (TMC) as the aqueous-phase and organic-phase monomers by interfacial polymerization (IP) reaction, to fabricate positively charged TA-MoS2 composite nanofiltration membrane, and the surface morphology, structure, surface properties and permeation separation performance were studied. The results showed that the surface of the modified membrane showed a peak-like raised structure, increased roughness, enhanced hydrophilicity, and improved anti-pollution performance. Under the operating pressure of 0.4 MPa, the pure water flux was 91.5 L/m2·h·MPa, which was 2.13 times as that of the PA membrane, MgCl2 retention rate was 92.78%, and the performance remained stable during the 24 h continuous operation. It provides ideas for the preparation of composite nanofiltration membrane with high permeate flux.
Fe/Ce-ZnO composite photocatalysts were synthesized using zinc acetate, ferric nitrate, and cerium nitrate through hydrothermal methods with varying levels of cerium doping. Their ability to degrade Rhodamine B (RhB) under ultraviolet light was assessed, and their properties were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and Mott-Schottky (M-S) techniques. The photocatalytic effects at different calcination temperatures were evaluated, and a mechanism for RhB photodegradation was proposed based on free radical trapping and electron spin resonance tests. The Fe0.02-Ce0.1ZnO samples exhibited a degradation rate of 95.5% after four cycles, with only a 3.6% decrease in efficiency.
Conductive silver paste is mainly composed of silver powder, resin, solvent, and additives. According to the properties of the solvent, it can be divided into water-based and oil-based conductive silver paste. The former has high potential for application in the field of flexible electronic technology due to its green and environmentally friendly characteristics. This article uses the controlled variable method to compare experiments and finds that the solvent ratio and type not only improve the conductivity of silver paste, but also affect its drying rate and sintering temperature. Among them, glycerol can significantly improve the conductivity of silver paste, and ethanol can improve the natural drying rate of silver paste. The final determined ratio of conductive silver paste is silver powder:resin:solvent of 125:55:53, and the ratio of water-based solvent is ethanol:propylene glycol of 161:339. This silver paste has high conductivity (ρ=2.25×10-5 Ω·cm), adhesion (5 B), excellent comprehensiveness, and green environmental protection characteristics, and can also achieve RFID applications.
Ti-Mn based AB2 Laves phase alloy has the advantages of acceptable hydrogen storage capacity (about 2wt%) at room temperature, good hydrogen absorption/desorption kinetics, good cycling performance, easy activation and low cost. The results show that TiMn2 has the best hydrogen storage performance for homogeneous single phase. However, there are also some problems, such as weak cycle stability, large slope of hydrogen absorption and dehydrogenation platform, and serious hysteresis of hydrogen absorption and desorption. From many research and practical application requirements, element substitution is still the main method to improve the hydrogen storage properties of alloys. Among them, the addition of V can increase the position of hydrogen gap and effectively reduce the platform pressure without reducing the hydrogen storage capacity. Therefore, based on the phase structure of Ti-V-Mn-based hydrogen storage alloy, this paper describes the changes of C14 Laves phase and body-centered cubic (BCC) phase and the correlation between them, and systematically summarizes the effects of element addition or substitution, preparation process and heat treatment process on the hydrogen storage properties of Ti-V-Mn based alloy.
High-entropy materials have great application prospects in the field of high-performance energy storage materials due to the synergistic effect between its multiple components, and thus showing excellent mechanical properties, high temperature stability and chemical stability. In recent years, the application of high entropy materials in the anode of alkali metal secondary batteries has received wide attention. High-entropy oxides, high-entropy prussian blue and high-entropy alloys show not only excellent electrochemical activity but also good cycling stability when they are used as anode materials for lithium-ion, sodium-ion, potassium-ion and lithium-sulfur batteries. Based on this, this paper reviews the research progress in recent years on the application of high entropy cathode materials in alkali metal secondary batteries, analyzes the performances of these materials, and looks forward to the future development trend and potential application prospects of these materials in this field.
In recent years, high entropy oxides, which are composed of five or more metallic elements in equimolar or near-equimolar highly dispersed and disordered structures, have received extensive attention. The high entropy oxides including rock salt, spinel, perovskite and fluorite, have good application prospects in the fields of energy storage, catalysis, absorption and heat insulation. In this paper, the recent advances in the preparation method of high entropy oxides including solid phase reaction, spray pyrolysis, co-precipitation, hydrothermal synthesis, sol-gel, solution combustion synthesis and laser method are reviewed, and their advantages and disadvantages are compared in detail. On this basis, various modification strategies of high entropy oxides are summarized. The problems in the synthesis of high entropy oxides are presented, and the future development trend of high entropy oxides is prospected.
Foams made from conventional materials have demonstrated high performance, stability, etc. in the global context of limited petrochemical resources and energy scarcity. These materials are not renewable, which will result in resource waste and add to the environmental load, and they have significant pollution and petrochemical resource origins. The fact that biomass fiber materials are renewable, eco-friendly, non-polluting, and green, which has made them quite popular. This study examines the development of research on fiber-based foams in the last several years, with an emphasis on the fiber pretreatment, foaming procedure, foaming formulations, and possible uses. It also anticipates the future, when cellulose-based foams will be promoted, produced in vast quantities, and designed with optimal efficiency.
With the continuous progress of protection technology and the continuous enhancement of human protection awareness, advanced human protection materials have received extensive attention. Traditional protective materials and equipment can no longer meet people's protection needs due to problems such as bulky wear and poor cushioning performance, and it is urgent to research and develop new lightweight, flexible, intelligent and human protective materials with excellent protective performance and comfortable wearing performance. As a new type of functional material, shear thickening material (STM) has shown broad application prospects and development potential in the field of human protection due to its unique flexibility and impact response. This article focuses on the research status of STM in recent years. Shear thickening mechanism and influencing factors of STM are summarized. Research progress in the field of human protection at home and abroad are reviewed. Preliminary prospects for future research and development of STM are finally provided.
Dielectric layer based on ceramic is very important for energy storage capacitors. Composite ceramics are one of the important ways to modify dielectrics. The tungsten bronze structured Ba5LaTi3Ta7O30 (BLTT) doped perovskite (Bi0.5Na0.5)TiO3 (BNT) ceramics were proposed, and further modified by the Sm2O3 dopants. The phase transition of tye BNT ceramics from ferroelectric to relaxor ferroelectric at room temperature was achieved by introducing BLTT and Sm2O3. Lattice distortion was induced when the Sm dissolved in the lattice of BNT-BLTT. The growth of rod grains was promoted, and the growth of spherical grain was inhibited. The temperature dependent dielectric spectra illustrated that the composite ceramics were relaxation ferroelectric, improving the energy storage density and efficiency. High recoverable energy storage density (1.6 J/cm3) and energy storage efficiency (74%) were obtained at 1.2wt% Sm2O3 content and 160 kV/cm. High practical discharge energy density of (1.56 J/cm3) and power density of (63.4 MW/cm3) could also be achieved at 1.2wt% Sm2O3 content and 150 kV/cm. Therefore, the composite ceramics constructed by perovskite and tungsten bronze phases have great potential in energy storage capacitors.
A gypsum modified solid waste based adhesive powder was prepared using calcium carbide slag and saltpeter as raw materials, and gypsum as a doping material. The effect of gypsum doping amount on the lattice structure, micro morphology, mechanical properties, and failure mode of solid waste based adhesive powder were explored. The results showed that the addition of an appropriate amount of gypsum effectively delayed the setting time of the adhesive powder and reduced its flowability, as well as significantly promoted the hydration reaction of the adhesive powder, accelerated the consumption of cement clinker, reduced the number of pores in the adhesive powder, and improved the compactness. With the increase of gypsum doping, the chemical binding water content, compressive strength, and splitting tensile strength of the adhesive powder first increase and then decrease. At 28 d of age, when the gypsum doping amount was 5wt%, the chemical bonding water content, compressive strength, and splitting tensile strength of the adhesive powder reached their maximum values of 9.3%, 3.06 MPa and 2.82 MPa, respectively, and their maximum stress and strain reached 205.3 N and 3.9 mm, respectively. This sample had the highest structural integrity, the least number of cracks and surface detachment phenomena, and the best mechanical properties in the failure experiment. Overall, the optimal doping amount of gypsum was 5wt%.
Nanodomains are non-periodic distorted areas in thermoelastic martensitic transformation materials, profoundly affecting the phase transformation behaviors of the materials. However, their influence on the mechanical behaviors remains unclear. This study focused on different compositions of nanodomain-containing NiTiNb alloy wires prepared by vacuum induction melting, forging, cold deformation, and annealing. The microstructure was characterized using transmission electron microscopy (TEM), the transformation behaviors were investigated by probing electrical resistance at various temperatures(ER), and the mechanical behaviors were characterized using a universal tensile testing machine at different temperatures. The results show that the martensitic transformation and mechanical behaviors of NiTiNb alloys are both closely related to the difference between Ni and Ti+Nb content (atomic percentage). Tuning the content difference leads to nanodomained structure over a wide temperature range. Moreover, when T<Mσs, the larger the content difference, the smaller the dσ/dT, and the alloy exhibits high strength over a wider temperature range. When T>Mσs, large difference in Nb and Ti+Nb content corresponds to simultaneously improved the strength and plasticity.
Amorphous hydrogen storage materials have excellent hydrogen absorption and release capabilities. Their microstructures are closely related to the corresponding crystalline phases, but it is not possible to describe this relationship at the atomic scale. In this paper, the cluster plus linked atom model is introduced and extended, and a dual-cluster model is proposed, namely C1 {[principal cluster]1 (glue atoms) 1 or 3} + C2 {[principal cluster]2 (glue atoms) 1 or 3}, in which C1 and C2 conform to the lever law and explain the structural heritability of amorphous materials and their corresponding alloy phases at the cluster scale. Each alloy phase can construct multiple clusters, and the cluster that best reflects the alloy phase structure should be selected as the main cluster. Firstly, the first nearest neighbor coordination polyhedron with the highest density is selected as the principal cluster according to the relative atomic number density method, then the ratio of the alloy phases on both sides of the deep eutectic composition is calculated according to the lever law and the dual-cluster formula is constructed, and finally the single cluster combination with the closest composition to the experimental value and the valence electron number conforming to the law of 8n is selected as the dual-cluster formula of the hydrogen storage material. The model is used to analyze the hydrogen storage materials in the Mg-Ni system, and the results are in good agreement with the experimental results. The correlation between the deep eutectic composition and the eutectic phase is revealed, which provides a feasible method for the composition design of bulk metal glass.
Janus β-Te2S has been predicted to be a novel two-dimensional material with potential applications in the optoelectronic field. This study employs first-principles calculations based on density functional theory to systematically investigate the effects of single vacancies, double vacancies, and Stone-Wales (SW) defects on the electronic structure and optical properties of monolayer Janus β-Te2S. The results indicate that the formation energies of various defect types in β-Te2S range from 0.45 to 1.12 eV, which are generally lower than the corresponding defect formation energies in other similarly structured two-dimensional materials. This suggests that β-Te2S is more prone to forming defect structures under experimental conditions. After defect formation, β-Te2S exhibits varying degrees of structural distortion, with localized energy levels appearing in its band structure that are related to the defect types. The isolation of these localized energy levels is further influenced by the defect concentration. Notably, β-Te2S with a type of SW defects transitions from an indirect bandgap semiconductor to a direct bandgap semiconductor without introducing localized energy levels. Additionally, defect structures significantly impact the optical absorption properties of β-Te2S. Defects reduce the peak values of optical absorption in the ultraviolet (UV) region to varying extents, and certain defect types induce new absorption peaks in the extreme UV and visible light regions. This research provides theoretical support for the experimental preparation of β-Te2S and offers references for designing optoelectronic devices through defect engineering.
With the development of science and technology, gallium is widely used in semiconductor, magnetic materials, medical devices and other fields. However, the content of gallium in nature is very low, and there are no independent mineral deposits that can directly extract gallium. Therefore, seeking new and effective methods to extract and recover gallium has gradually become the focus of attention. To solve the above problems, in this work, the sulfonic acid group in 2-aminoethanesulfonic acid (SEA) can form a coordination effect with Ga (Ⅲ), and glycidyl methacrylate (GMA) is grafted to D314 resin by radical polymerization using D314 macroporous anion exchange resin as the carrier to obtain D314-G-PGMA. Secondly, a new adsorption material, SEAD314, was prepared by using the ring-opening reaction between SEA energy and PGMA. The effect of modification conditions on the adsorption capacity and the adsorption properties of SEAD314 on Ga (Ⅲ) were investigated by infrared characterization of its structure. The results showed that SEAD314 exhibited excellent adsorption properties for Ga (Ⅲ), and the optimum modification conditions were obtained at SEA dosage of 2 g, modification temperature of 60 ℃ and reaction time of 8 h. Under the condition of 25 ℃ and pH of 2, the adsorption equilibrium was reached for 22 h, and the equilibrium adsorption capacity of Ga (Ⅲ) was 288.81 mg/g. The adsorption process was consistent with Lagergren's quasi-first-order model, and the isothermal fitting curve showed that the adsorption process of the material belonged to Langmuir monolayer adsorption. In addition, the adsorption material has good repeatability.
The Pr/TiO2 and Gd/TiO2 photocatalysts were prepared by rare earth ion doping modification of nano-TiO2 using Pr(NO3)3·6H2O and Gd(NO3)3·6H2O. The MB solution was used to simulate the photocatalytic degradation of the printing and dyeing wastewater. The impact of rare earth-doped modified TiO2 on the photocatalytic activity and the optimal doping amount were investigated. The results show that the light absorption of Pr/TiO2 and Gd/TiO2 exhibited a red shift after doping with Pr and Gd, and the Eg decreased to about 3.0 eV, which was about 7% lower than that of unmodified TiO2, and the photocatalytic activities were effectively improved. In the photocatalytic degradation experiment, the best degradation effect of printing and dyeing wastewater was achieved when the Pr and Gd doping amounts were 1.0% and 1.5%, respectively. The equilibrium degradation rates of Pr/TiO2 and Gd/TiO2 photocatalysts were 1.45 times and 1.64 times higher than those of the pristine TiO2 under ultraviolet light, respectively. Meanwhile, under visible light, these rates were 1.67 times and 1.73 times higher than those of the pristine TiO2. These results indicate that the photocatalytic activities of rare earth Pr and Gd ions doped nano-TiO2 were significantly improved.
Hydrogen evolution reaction is a critical step in water electrolysis for sustainable hydrogen production, but its widespread application is limited by the high cost and scarcity of precious metal catalysts. To address this, nanoporous high-entropy oxides were synthesized via chemical dealloying, offering a high surface area and abundant active sites. Mo doping can effectively promote the synergistic effect between transition metal atoms and significantly improve the charge transfer efficiency. Density functional theory simulations further reveal the optimization of the electronic structure on the catalyst surface and its enhancement of active sites. Electrochemical tests demonstrated low overpotential (138 mV) at -50 mA/cm2 and excellent durability, highlighting the potential of high-entropy oxide as cost-effective, high-performance electrocatalysts for HER in alkaline media.
Compared with crystalline silicon cells, organic photovoltaics (OPV) have been widely concerned for their advantages such as soft color, translucency and low-cost large-area manufacturing. Zinc oxide (ZnO) has become one of the key materials of OPVs electron transport layer due to its advantages in electron transport, environmental friendliness and low temperature solution processing. However, ZnO nanoparticles usually have a large number of surface defects which affect their carrier transport performance. Therefore, the electrical properties of ZnO need to be further improved. In this paper, the effect of boron doped ZnO as electron transport layer (B-ZnO) on the photoelectric properties of OPVs was studied by mixing boric acid and zinc oxide solution with different concentrations and adjusting and optimizing the mixing ratio. When the doping ratio is 8%, the maximum energy conversion efficiency of B-Zno-based OPVs under a standard sunlight has reached 8.76%, which is 8.2% higher than that of ZnO-based devices (8.10%). This is because boric acid doping makes the ZnO electron transport layer obtain better surface morphology and better electrical properties, reduce the interfacial defect state density and increase the built-in potential of the device, and thus improve the performance of the device. This study has provided a new idea and method for the convenient application of ZnO element doping in high efficiency OPVs.
Tetrahedral barium titanate (BaTiO3) powders have extremely high dielectric constant values and are the basic materials to manufacture the dielectric layers with high capacity of the multilayer ceramic capacitors (MLCC). The barium titanate powders prepared by direct hydrothermal method have the advantages of low impurities, uniform particles, easy dispersion, good chemical uniformity, and good crystallinity. In this paper, the relationships between the reaction conditions (hydrothermal reaction temperature, reaction time, feeding ratio of barium titanium precursor, alkalinity of reaction system) and the properties of the barium titanate nano-powders were investigated in detail. The mechanism of the direct hydrothermal preparation of barium titanate powders was also discussed. The hydrothermal reaction process was optimized, and the ultrafine tetragonal BaTiO3 powders with the average particle size of 150 nm, axial ratio of c/a of 1.0106, and crystallinity of 10.6 were successfully prepared through the optimized conditions.
To investigate the effects of different annealing temperatures on the microstructure and mechanical properties of cobalt emitter, high-purity cobalt powder was smelted and hot-processed to prepare cobalt emitter for self-powered neutron detectors. The samples were characterized using electron backscatter diffraction (EBSD) technology. Experimental results showed that as the annealing temperature increased from 600 ℃ to 900 ℃, the grain size of the cobalt emitter increased from 2.69 μm to 19.79 μm. The FCC phase exhibited random grain orientations with no significant preferred orientation as the annealing temperature rose. With increasing temperature, the FCC phase proportion decreased from 29.7% to 5.4%, while the HCP phase showed random textures. Notably, the FCC phase retained a {110}〈111〉 texture within the 600-800 ℃ range. The geometrically necessary dislocation (GND) density of the cobalt emitters varied between (0.37-0.81)×1014 /m2 with increasing annealing temperature. Additionally, the tensile strength, yield strength, and hardness exhibited a decreasing trend, while the elongation improved from 3.2% to 8.7%.
Using poplar fiber and polylactic acid as raw materials, surface modification of poplar fiber was carried out in advance through silane coupling agent KH-550, and then the modified poplar fiber was mixed with polylactic acid through melt blending process to prepare wood fiber-polylactic acid composite material. The effect of KH-550 treatment time on the phase structure, microstructure, spectral properties, and water contact angle of poplar fibers was studied, and the influence of KH-550 treatment time on the microstructure, mechanical properties, and water resistance of wood fiber-polylactic acid composite materials was analyzed. The results showed that with the increase of KH-550 treatment time, the crystallinity of wood fibers was improved, a large number of protrusions appeared on the surface, the water contact angle gradually increased, and the wettability decreased. When the KH-550 treatment time was 9 h, the reaction between the silane coupling agent and the surface of the wood fiber gradually reached saturation, and the roughness of the wood fiber surface tended to stabilize. With the increased of KH-550 treatment time, the impact strength, static flexural strength, and elastic modulus of the wood fiber-polylactic acid composite material first increased and then decreased, while the water absorption rate and water absorption thickness expansion rate first rapidly increased and then gradually stabilized. When the processing time of KH-550 was 9 h, the impact strength, static flexural strength, and elastic modulus of the composite material reached their maximum values of 8.5, 31.5 MPa and 40.3 GPa, respectively. The water absorption rate and water absorption thickness expansion rate of the sample reached saturation at 75 h, with the lowest values of 12.7% and 6.9%, respectively, indicating the strongest water resistance.
The preparation of superhydrophobic concrete entailed the immersion of the concrete in a sodium laurate solution, which served as the superhydrophobic modifying solvent. Effects of sodium laurate solution concentration and immersion time on contact angle of concrete, stain resistance and stripping resistance was investigated, and the optimal concentration and immersion time of sodium laurate solution were identified. Scanning electron microscopy (SEM) was employed to analyze the hydration products and microstructure of the concrete surface, and Fourier infrared spectroscopy (FT-IR) was utilized to substantiate the chemical reaction between the sodium laurate solution and concrete. The findings indicate that as the sodium laurate solution concentration is 1.5% and the immersion time is 1 minute, the contact angle of the superhydrophobic concrete is 155.2° and the rolling angle is 8.4°. In comparison to conventional concrete, the concrete treated with a sodium laurate solution exhibits enhanced self-cleaning properties and stain resistance. Following 30 cycles of strong tape stripping, the contact angle of the concrete surface is reduced to 140.6°, demonstrating the maintenance of effective hydrophobic performance.
The modified polyurea was prepared by using diphenylmethane diisocyanate, polypropylene glycol, polyoxypropylene diamine, diethyltoluenediamine and 4, 4′-bis-sec-butylaminodiphenylmethane as main raw materials, and nano-microcrystalline cellulose modified by 3-glycidoxypropyl trimethoxysilane as reinforcing material. The polyurea was tested and characterized by Fourier transform infrared spectrometer, X-ray diffractometer, scanning electron microscope and impact tester. The results show that when the content of nano-microcrystalline cellulose in polyurea was 0.4%, the tensile strength of polyurea reached 85 MPa, the elongation at break was 43%, and the impact strength reached 40.3 kJ/m2. The polyurea reinforced by nano-microcrystalline cellulose showed good mechanical properties.
Ti3C2Tx material shows remarkable potential in electromagnetic wave energy dissipation with its excellent electrical conductivity. In order to construct Ti3C2Tx composites with high absorption properties, a Ti3C2Tx@CNTs/Ni-HS hollow sphere composite with a double-shell structure was prepared by electrostatic self-assembly method in this paper. The microscopic morphology, physical phase structure, electromagnetic properties and wave-absorbing properties of the composite were investigated by means of scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, laser Raman spectrometer and vector network analyzer. The results show that this structure cleverly constructs a confined dissipation cage, in which the outer CNTs/Ni structure restricts the electron transfer between spheres and effectively prevents the self-stacking phenomenon, and the closely contacted Ti3C2Tx inner structure forms a continuous conductive path, which significantly enhances the dissipation efficiency of electromagnetic wave energy. The Ti3C2Tx@CNTs/Ni-HS-600 hollow sphere composite material achieves a minimum reflection loss of -59.88 dB at a mass ratio of only 15 wt%, which is significantly better than similar materials. This excellent performance is attributed to the well-designed conductive paths in the confined dissipative cages, which ensures the lightweight of the material while achieving efficient electromagnetic wave absorption. This study not only provides new ideas for the design of high-performance electromagnetic wave absorbers, but also provides valuable references for research in related fields.
Exploring the diffusion behavior of regenerant in aged asphalt system at room temperature is helpful to the study of cold regeneration of asphalt mixture. The effects of waste edible oil on the penetration, functional groups, complex modulus and phase angle of aged asphalt under different diffusion time were studied from macro and micro scales by immersion method, Fourier transform infrared spectroscopy (FTIR) test and rotary rheometer test, and the test results were compared and analyzed. At the same time, based on the molecular dynamics theory, the molecular model of waste edible oil and aged asphalt was established, and the interface diffusion model was constructed. According to the diffusion coefficient, the diffusion behavior of the two in the system was revealed. The results show that waste edible oil can restore the basic technical performance of aged asphalt to a certain extent at room temperature, supplement the light components missing due to aging, and restore its rheological properties. In addition, molecular dynamics simulation shows that the movement speed of waste edible oil molecules is faster than that of aged asphalt molecules, indicating that waste edible oil can soften aged asphalt in a short time. Therefore, it can be seen that the efficiency of wetting and softening aging asphalt of waste edible oil at room temperature is good.
In order to study the application of highly absorbent polymerss in soil remediation, this paper prepared Urea@PAA/RS/HA highly absorbent polymerss by aqueous solution polymerization using acrylic acid (AA) as the monomer, and pea straw powder (RS), humic acid (HA), and urea (Urea) as the main raw materials. The structure, morphology and thermal stability of the polymerss were tested using infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The effects of the synthesis conditions, such as acrylic acid, humic acid, urea, initiator, cross-linking agent dosage and degree of neutralization, on the liquid-absorbing capacity of the polymers were investigated, and the polymers prepared under the optimal synthesis conditions had a water-absorbing capacity of 473 g/g and a brine-absorbing performance of 62.7 g/g. The water-absorbing and swelling behavior of Urea@PAA/RS/HA in deionized water was analyzed by using the quasi second-order kinetic model. The absorptive properties of the polymers in soil filtrate and heavy metal ion solutions were investigated, as well as the effects of polymers type and dosage on soil physicochemical properties, water holding and water retention capacity.
The atmospheric pressure air plasma was used to treat the surface of ETFE to achieve surface modification of ETFE, and the adhesive properties of treated ETFE were investigated. The changes in the composition, structure, wettability, and bonding properties of ETFE before and after plasma treatment were analyzed using total reflectance infrared spectroscopy (ATR-FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), water contact angle (WCA), and mechanical property tests. The impact of different treatment time, power, and placement times on the wettability and adhesive properties of ETFE surfaces was investigated. The results show that the plasma treatment would etch the ETFE surface to form a rough structure, and the optimal treatment conditions were determined to be 650 W plasma treatment for 30 seconds. The adhesive strength of the ETFE and the epoxy resin increased from 0.22 MPa to 1.78 MPa. Furthermore, although the contact angle of the plasma-treated ETFE increased to 84° after 336 hours, the bond strength remained above 0.93 MPa, indicating that the plasma treatment could effectively improve the adhesive properties of ETFE over an extended period.
The effects of electrolyte concentration and pH value on the stability of weakly alkaline silica sol for precision casting were studied using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Zeta potential analyzer. The results showed that as the electrolyte concentration increased, the stability time of the silica sol significantly shortened, and the gelling speed accelerated. Kinetic analysis indicated that the coagulation ability of K+ was greater than that of Na+. Within the pH range of 6.0 to 9.0, the silica sol remained relatively stable due to sufficient electrostatic repulsion on the surface of the colloidal particles. However, when the pH value was below 4.0 or above 10.0, the changes in H+ concentration weakened the electrostatic repulsion between the colloidal particles, thereby reducing the stability of the silica sol. In conclusion, electrolyte concentration and pH value significantly affect the stability of silica sol, and the research findings provide important theoretical support for optimizing precision casting processes.
A novel polyepoxysuccinic acid derivative (PESA-Lcy-Sea) was prepared by modifying polyepoxysuccinic acid with L-cysteine and taurine in order to broaden its application range. The obtained PESA-Lcy-Sea and its quaternary complex are used as corrosion inhibitors for Q235 carbon steel (QCA) in seawater medium. The experimental results showed that when PESA-Lcy Sea, HAPP, Zn2+ and Na2WO4 are 650 mg/L, 10 mg/L, 4 mg/ L and 40 mg/L respectively, they had a good synergistic corrosion inhibition effect, and the corrosion inhibition efficiency reached 94.59%. The PESA-Lcy-Sea quaternary complex could inhibit both negative and anode reactions and reduced the corrosion current. EIS proves that the addition of quaternary complexes enhances the resistance of surface charge transfer of QCA. SEM, AFM, XPS and CA tests showed that the corrosion inhibitor inhibited the corrosion by forming a protective film on the surface of QCA and the PESA-Lcy-Sea quaternary complex had better corrosion inhibition effect. This study provided technical support for the development of natural seawater as corrosion inhibitor in cooling water.