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Binary composites WO3/g-C3N4 in porous morphology: Facile construction, characterization, and reinforced visible light photocatalytic activity
摘要： Various WO3/g-C3N4 binary composites were constructed by a facile one-step calcination procedure and then systematically analyzed for chemophysical properties. Interestingly, these resultant composites showed porous morphology in combination with some tubular structures, where both components were closely contacted to generate heterojunction structures. Accordingly, these composites possessed reinforced visible-light absorption capability and enlarged specific surface areas in texture. These microstructural, morphological, and electronic merits ensured the strengthened photocatalytic performance toward degradation of rhodamine B (RhB) and methylene blue (MB) under visible light irradiation. In addition, on base of reactive species entrapping experiments and analytical results, a probable photocatalysis mechanism was speculated as a “Z-scheme” manner instead of conventional Type II path.
关键词： WO3,Photocatalytic degradation,Mechanism,Porous morphology,Binary composites,g-C3N4
更新于2025-11-14 17:04:02
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Reversible Self-Healing for Preserving Optical Transparency and Repairing Mechanical Damage in Composites
摘要： This research concentrates on the healing of optical properties, roughness, contact angle hysteresis, and shallow scratches in polymer/nanoparticle composites. A series of ternary composite blends [epoxy/halloysite nanotubes (HNTs)/cellulose acetate butyrate (CAB)] with various CAB concentrations were fabricated and subjected to a series of mechanical damages. The optimized concentration of nanoparticle is 1.0 vol% and for CAB concentration of 3.0 vol% based on the mechanical reinforcement and wear-resistance. Nanoscale scratching, micro-level falling-sand test, and macro-level Taber Abrasions were utilized to damage the surfaces. The induced damage (roughness and surface scratch up to hundreds of nanometers in depth) healed upon heating. At any temperatures above the softening transition of the semi-interpenetrating network structure of the polymer composites, CAB migrates into the micro-cracks, and the essential mechanical parameters (modulus, strength, strain-to-failure) are recovered; in our particular epoxy/HNTs/CAB system, optical transparency is also recovered efficiently. CAB also moves to the macroscopic air/specimen interface and favorably modifies the surface properties, reducing the roll-off angles of water droplets from ~90o to ~20o. Through an appropriate choice of CAB additives with different molecular weight, the healing temperature can be tailored.
关键词： mechanical,multi-functional,transparent,composites,self-healing
更新于2025-10-22 19:40:53
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Fast-curing halogen-free flame-retardant epoxy resins and their application in glass fiber-reinforced composites
摘要： A series of novel fast-curing halogen-free flame-retardant epoxy resins were formulated and used to prepare glass fiber-reinforced composites. Dynamic mechanical analysis showed that the optimized epoxy system could be completely cured in 0.5 h at 150°C and had a glass transition temperature (Tg) of above 130°C. The optimized epoxy system was also used as matrix resin to make glass fiber prepregs and composite panels. The flame-retardant properties of the glass fiber-reinforced composites were investigated, including the limiting oxygen index (LOI) and flaming, smoke and toxicity properties. The glass fiber-reinforced composite had good flame retardancy with a UL-94 V-1 rating and high LOI of ≥36%. More significantly, the composite based on the flame-retardant epoxy resin showed lower smoke density compared with those based on phenolic resins. Finally, the glass fiber prepregs were used to fabricate honeycomb sandwich composites. The peel strength of the epoxy-based composites was almost twice that of the composites based on phenolic resin.
关键词： prepregs,fast cure,glass fiber-reinforced composites,halogen-free flame retardancy,epoxy resins
更新于2025-09-23 15:23:52
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A Numerical Study of Densification Behavior of Silicon Carbide Matrix Composites in Isothermal Chemical Vapor Infiltration
摘要： We studied the characteristics of two-scale pore structure of preform in the deposition process and the mass transfer of reactant gas in dual-scale pores, and observed the physiochemical phenomenon associated with the reaction. Thereby, we established mathematical models on two scales, respectively, preform and reactor. These models were used for the numerical simulation of the process of ceramic matrix composites densified by isothermal chemical vapor infiltration (ICVI). The models were used to carry out a systematic study on the influence of process conditions and the preform structure on the densification behaviors. The most important findings of our study are that the processing time could be reduced by about 50% without compromising the quality of the material, if the processing temperature is 950-1 000 ℃ for the first 70 hours and then raised to 1 100 ℃.
关键词： isothermal chemical vapor infiltration,fiber preform structure,densification behavior,ceramic matrix composites,process parameters
更新于2025-09-23 15:23:52
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Synthesis and characterization of composites ZnZr for the photocatalytic degradation of phenolic molecules. Addition effect of ZrO <sub/>2</sub> over hydrozincite Zn <sub/>5</sub> (OH) <sub/>6</sub> (CO <sub/>3</sub> ) <sub/>2</sub>
摘要： BACKGROUND: Composite materials ZrO2/Zn5(OH)6(CO3)2 were prepared in only one step by chemical coprecipitation and thermal hydrolysis of urea. ZrO2 was added at 5, 8 and 10 mol%. The samples were dried at 80°C and characterized by adsorption-desorption of N2 isotherms, XRD, SEM, techniques and DRS, UV-Vis, FTIR and XPS spectroscopies. The materials were assessed in the photodegradation of phenol and polychlorinated phenolic molecules under UV-light irradiation. The possible mechanism was discussed from studies that corroborated o discarded the formation of the species ?OH, ?O2- and h+. RESULTS: The addition of ZrO2 to Zn5(OH)6(CO3)2 resulted in a composite material with high photoactivity. Being the most efficient the sample with 8 mol% of ZrO2. The photodegradation enhancement was partly achieved by an increment in the specific surface area and principally due to localized states originated in the composite interphase which improve the charges transfer. It was found by XPS study that the ZrO2 addition increment the oxygen vacancies which enhance the organic molecule photodegradation via direct holes attack. CONCLUSION: The composite system ZnZr can be an excellent alternative for the persistent organic pollutants photodegradation due to the low cost, high stability and null toxicity of the support Zn5(OH)6(CO3)2.
关键词： ZrO2,hydrozincite,phenol-chlorophenols photodegradation,composites
更新于2025-09-23 15:23:52
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Improvement of nickel nanocomposite coatings by combining zinc-doped TiO2 nanoparticles
摘要： Pure nickel and compound of nickel coatings (Ni-TiO2 and Ni-Zn/TiO2) were coated on the steel material using Watts bath with the electrodeposition conditions. Effect of the nanoparticle type and current density on the coating structure, surface morphology of the coating, hardness of the coating, and the corrosion properties of the coatings are presented. Phase and elemental analysis of the coatings were carried out by XRD and EDS techniques, respectively. SEM was used to investigate the surface morphology of the coatings, and Vickers microhardness values were measured to determine the hardness variation of the coatings. NaCl solution (3.5 wt%) was used to evaluate the corrosion properties of the coatings by the potentiodynamic polarization tests. Corrosion current density of 2.890 μA/cm2 for pure nickel coating was improved to 0.379 μA/cm2 by the coating of Zn-doped TiO2 nanoparticles at the 7A/dm2 current density. Microhardness of the Zn-doped TiO2 coating was improved compared to the pure Ni coating.
关键词： Sol-gel processes,Metal matrix composites,Nanoparticles,Composite coatings
更新于2025-09-23 15:23:52
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Optimizing P25-rGO composites for pesticides degradation: Elucidation of photo-mechanism
摘要： The junction of graphene oxide with TiO2 particles can help develop more efficient photocatalysts capable to harvest radiation in a wider range of the electromagnetic spectrum for real photocatalytic applications. The synthesis procedure of TiO2 P25-rGO composites was optimized to photodegrade a selected mixture of pesticides classified by EU as priority pollutants (alachlor, diuron, atrazine and isoproturon). The influence of temperature and time of hydrothermal method, as well as the effect of graphene oxide (GO) percentage added in the synthesis, was studied to obtain the nanocomposite that showed the highest photoactivity. Long time and moderate temperature have offered the best interaction between TiO2 P25 and rGO. GO was quantitatively reduced to rGO during the hydrothermal treatment, but maintains a higher level of disorder. The optimal GO loading was found around 0.25 wt. %, which allowed the photocatalyst achieve high photocatalytic performance both in phenol and pesticides photodegradation. Finally, in order to try to elucidate the photocatalytic mechanism of the selected mixture of pesticides three scavengers were employed: methanol to scavenge hydroxyl radicals, formic acid for the photogenerated holes, and copper (II) nitrate to quench the electrons of the conduction band. In conclusion, all these pesticides were mostly photodegraded by the hydroxyl radicals (HO?) produced from the photo-induced holes (h+); given that the oxidant species generated from electrons or mediated by direct mechanism were not relevant.
关键词： Scavengers,TiO2P25-reduced graphene oxide composites,Pesticides,Photo-mechanism
更新于2025-09-23 15:23:52
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Gamma irradiated poly (methyl methacrylate)-reduced graphene oxide composite thin films for multifunctional applications
摘要： Poly (methyl methacrylate) (PMMA)-Reduced Graphene Oxide (rGO) (PrGO) composite films were fabricated by solvent evaporation technique and exposed to gamma radiation at different dosages viz. 25 kGy, 50 kGy and 100 kGy. The XRD analysis revealed the phases of PMMA and rGO and further confirmed the semi-crystalline nature of PMMA. The irradiation also decreased the peak intensities of the functional groups of PMMA and rGO. At 50 kGy irradiation, lamellar structures were formed on the surface of the films (50 kGy) due to the thermal fluctuations whereas, at higher dosage (100 kGy), pores were formed. The surface roughness and contact angle were enhanced on 50 kGy sample. The drug impregnated PrGO50 and PrGO100 samples showed sustained and burst release of drug respectively and in addition exhibited a better zone of inhibition against E. coli bacteria. All the samples were hemocompatible in nature. Fibroblast proliferation was enhanced with no cytotoxic effect on 50 kGy samples. Hence, the gamma irradiated samples could be an excellent candidate for biosensing and biomedical applications.
关键词： Biomedical Applications,Polymer,Bioactive,Reduced-graphene oxide composites
更新于2025-09-23 15:23:52
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Transparent wood bearing a shielding effect to infrared heat and ultraviolet via incorporation of modified antimony-doped tin oxide nanoparticles
摘要： Optically transparent wood (TW) is an emerging candidate for applications in energy efficient buildings. In this study, anti-ultraviolet and infrared heat shielding TW was prepared based on the delignification of the wood's substrate. This was followed by infiltration of pre-polymerized methyl methacrylate (PMMA) with modified antimony-doped tin oxide (ATO) nanoparticles. The ATO addition enhanced the interfacial bonding among the compounds, which improved the fracture strength, leading to a high fracture strength of 96.4 MPa and modulus of 4.27 GPa with addition of 0.3% ATO. Furthermore, the obtained ATO/TW exhibited high transparency, excellent near infrared (NIR) heat shielding performance, and ultraviolet (UV) shielding properties according to the ultraviolet–visible spectrophotometer measurement, the infrared heat shielding simulation test, and the UV-shielding test. The TW treated with 0.3% ATO still maintained a very low thermal conductivity of around 0.2 W m?1 K?1. After addition of 0.7% ATO, the obtained TW had a quite low UV transmittance of ＜20%. The Aspergillus niger maintained high viability after UV irradiation treatment when shielded with TW treated with 0.7% ATO. The findings indicate that the multifunctional and durable ATO/TW has a potential to be used as energy-saving building material.
关键词： A. Nano composites,A. Wood,B. Ultraviolet shielding,B. Infrared heat shielding
更新于2025-09-23 15:23:52
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Study of the fabrication and organization properties of copper-based Ba<inf>1?x</inf>Sr<inf>x</inf>TiO<inf>3</inf> composites
摘要： Barium strontium titanate ceramic particles which have negative thermal expansion properties when it reaches reinforcement and copper which have high thermal conductivity are choosen as matrix of composites. Different content of strontium in barium strontium titanate ceramic particles reinforced copper matrix composites are prepared by Spark Plasma Sintering for electronic packaging applications. The methods of microstructure analysis are employed to observe the morphology of reinforcement and matrix in composites, and interfacial characteristics. Thermal expansion instrument and thermal conductivity equipment are used to test and analyze the thermal expansion and thermal conductive ability of the composites. And the conductivity of the composites is tested by intelligent resistance tester.
关键词： Thermal expansion ability,Barium strontium titanate,Copper matrix composites
更新于2025-09-23 15:22:29