nanocomposite

摘要： This study reports the successful synthesis of supported TiO2_Palygorskite nanocomposites by a one-pot dry mechanochemical route. Indeed, the elaboration procedure involved an in-situ reaction between accessories carbonates present in raw fibrous palygorskite clay and titanyl sulfate (TiOSO4) precursor under variable grinding conditions, essentially ball/solid matter mass ratio and rotation velocity. This yielded after air annealing at 600%C for 1 h to the immobilization of anatase TiO2 nanoparticles (≈8 nm of average size) as evidenced by XRD and TEM analyses. Once the conditions of elaboration were optimized, the photocatalytic properties were evaluated under 3 conditions: artificial UV radiation, artificial solar radiation (UV + visible range) and under dynamic solar illumination taking into account the discontinuities of the solar resource. The results allowed the estimation and comparison of the catalyst’s capabilities and showed its ability to work under natural irradiation. The so developed supported photocatalysts TiO2/Palygorskite exhibited a good activity towards the removal of Orange G (OG) dye from aqueous media under artificial UV and natural solar radiations.

摘要： A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants.The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology.Due to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is improved.At the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased.The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum.The main burning gaseous products are N2,CO_(2),CO,H2O,CH4,etc.After the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning condition.The progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants.This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

摘要： The concern with environmental preservation is a very current and relevant topic. Regarding polymers, the search for potentially ecofriendly matters has been the subject of scientific research. In this context, this work aimed to study the effect of adding nanocellulose (nCE) with 1, 3, and 5 wt.% on poly(butylene adipate-co-butylene terephthalate) (PBAT). Thermal, structural, relaxometric, and rheological assessments were carried out. Quantitative evaluation of PBAT copolymer by high field NMR revealed 56.4 and 43.6 m.% of the butylene adipate and butylene terephthalate segments, respectively. WAXD measurement on the deconvoluted diffraction patterns identified that nCE was a mixing of Cellulose I and Cellulose II polymorph structures. At any composition, nanocellulose interfered with the PBAT crystallisation process. Also, a series of new PBAT crystallographic planes appeared as a function of nanocellulose content. PBAT hydrogen molecular relaxation varied randomly with nanocellulose content and had a strong effect on the hydrogen relaxation. PBAT cold crystallisation and melting temperatures (Tcc and Tm) were almost unchangeable. Although Tcc did not change during polymer solidification from PBAT molten state, the sample’s degree of crystallinity varied with composition through the transcrystallization phenomenon. Nanocomposite thermal stability decreased possibly owing to the catalytic action of sulfonated amorphous cellulose chains. For the sample with 3 wt.% of nanocellulose, the highest values of complex viscosity and storage modulus were achieved.

摘要： Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen sublattice.Here we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in LSMO.Combined structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in NiO.Using the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport properties.The use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies.

摘要： Next-generation packaging materials are expected to have higher thermal conductivity,because the heat accumulated in high-performance electronic equipment should be removed to increase the service life of the equipment.At the same time,the dielectric loss of the material needs to be reduced to lessen signal delay and attenuation,especially for the applications under high frequency.In this work,we introduce nano-silicon carbide(SiC)and carbon nanotubes(CNTs)into the polystyrene(PS)and poly(methyl methacrylate)(PMMA)blends system.The design of two-way migration at the interface of CNTs and SiC nanoparticles is realized through the masterbatch method and processing technology control.As a result,the thermal conductivity is successfully increased up to 75%.Meanwhile,compared to the CNTs single-phase migration system,it effectively reduces the dielectric loss of the nanocomposite and optimizes the electrical insulation.This work has significant practical application value in the design of electronic device substrates and packaging materials,and provides an innovative methodology for the mesostructure design of multiphase nanocomposites.

摘要： The interest in CO_(2)conversion to value-added chemicals and fuels has increased in recent years as part of strategic eff orts to mitigate and use the excessive CO_(2)concentration in the atmosphere.Much attention has been given to developing two-dimensional catalytic materials with high-effi ciency CO_(2)adsorption capability and conversion yield.While several candidates are being investigated,MXenes stand out as one of the most promising catalysts and co-catalysts for CO_(2)reduction,given their excellent surface functionalities,unique layered structures,high surface areas,rich active sites,and high chemical sta-bility.This review aims to highlight research progress and recent developments in the application of MXene-based catalysts for CO_(2)conversion to value-added chemicals,paying special attention to photoreduction and electroreduction.Furthermore,the underlying photocatalytic and electrocatalytic CO_(2)conversion mechanisms are discussed.Finally,we provide an outlook for future research in this fi eld,including photoelectrocatalysis and photothermal CO_(2)reduction.

摘要： Waste is the main problem for the environment.Handling waste for various useful applications has a benefit for the future.This work has been studied for handling pineapple peel waste to make composite film bacterial cellulose nanocomposite membrane(BCNM)with addition graphite nanoplatelet(GNP).The concentration of GNP in the membrane influence the membrane properties.The bacterial cellulose(BC)pellicle was synthesized by using media from pineapple peel waste extract.BC pellicle is cleaned with water and NaOH solution to be free from impactors.BCNM is synthesized through the mechanical disintegration stage.The results of disintegration using high pressure homogenizer at 150 bar and five cycles.BCNM/GNP is synthesized with varying addition of GNP of 2.5,5.0,10 and 100 wt%of dry bacterial nanocellulose(BNC).The BC and GNP solution were dried in an oven for 14 h at 80°C.BCNM morphology was observed using SEM.GNP is dispersed and distributed in the BC matrix as reinforcement.FTIR analysis shows many peaks of BNC less pronounced with increasing of GNP.The higher concentration of GNP,the rougher of BCNM.The optimum tensile strength of BCNM was achieved after addition GNP of 2.5 wt%.

摘要： Polylactide(PLA)/poly(butylene adipate-co-terephthalate)(PBAT)blend nanocomposites including 3 wt%of cel-lulose nanocrystals(CNCs)were prepared by melt compounding method in a twin-screw extruder and an inter-nal mixer.Blend nanocomposites were formulated by diluting three different masterbatches prepared by solution casting method that contained 7 wt%of CNC.These masterbatches were:(m1)PLA/PBAT/CNC masterbatch;(m2)PLA/CNC masterbatch;and(m3)PBAT/CNC masterbatch.These were to explore how different prepara-tion methods affect the dispersion and localization of CNC and hence the properties of PLA/PBAT/CNC blend nanocomposites.Scanning electron microscopy(SEM)was used to study the structural changes of the blends.Rheological properties of PLA/PBAT blends and PLA/PBAT/CNC blend nanocomposites were also investigated.In the samples prepared by internal mixer,the rheological behavior of blend nanocomposite prepared through premixing of CNC particles with PLA showed a transition from liquid-like to a gel-like behavior.According to the rheological results and differential scanning calorimetry(DSC)analysis,it was found that the CNC overall enhanced the viscoelastic properties of blends and improved the PLA crystallization,respectively.Dynamic mechanical analysis(DMA)illustrated that the incorporation of CNC also enhanced the elastic modulus of PLA/PBAT blends specifically above the glass transition temperature of PLA.The expected improvements in mechanical properties did not occur due to the possible existence of residual solvent in the blends.

摘要： Nanocomposite hydrogels are the combination of known components that are a hydrogel and nanometre-sized fillers,typically leading to improved mechanical properties or new functionalities.With simplicity of design and ease of synthesis,recent advances have highlighted that this family of hydrogels holds the significant promise of application in diverse biomedical and engineering fields.The elaborate design and investigation as well as suitable application of nanocomposite hydrogels require the synergy of mechanics,materials science,engineering,and biology.Despite similarities in design and fabrication,the data of mechanical properties for nanocomposite hydrogels scatter in a large space.It is worthwhile comparing various nanocomposite hydrogels for similarities and differences in mechanical properties to aid in designing novel hydrogels with extreme properties,and guide practical applications.This review aims to fill,in the literature,the missing gap of addressing mechanical measurement methods and comparison of mechanical properties in this ever-evolving broad area of research.Finally,the challenges and future research opportunities are highlighted.

摘要： Magnesium oxide was found to have high-phosphate-affinity as an effective component to enhance the phosphate removal ability of common adsorbent materials.However,the currently prepared MgO-based hybrid adsorbents by conventional methods still suffer from the limited low loading of MgO and inferior removal performances,much far away from practical application.In this study,an ingenious carbon coated MgO nanocomposite is designed by directly burning magnesium in CO_(2),a well-known textbook reaction.X-ray diffraction analysis,scanning electron microscope and aberration-corrected high-resolution transmission electron microscope demonstrate the sample is well prepared.Consequently,the high content of nanosized MgO combined with defect-rich carbon layer brings unprecedented phosphate removal capacity of 1135.0 mg/g,removal rate of 99% and benign compatibility with coexisting anions and solution pH.Furthermore,the removal mechanism is also investigated in detail by characterizing the sample before and after adsorption.

摘要： Iron oxides are usually preloaded within nanoporous supports of large particle size to improvetheir feasibility for practical environmental remediation including arsenic and heavy metals removal, andeffect of co-ions on the performance of the resulting composites has been well investigated. However, noattempt has been made to investigate their adsorption behavior of heavy metals in the presence ofcounter-ions, such as sulfate. In this study, two hybrid sorbents (denoted as HFO-PS-and HFO-PS0respectively) were prepared by loading hydrous ferric oxide (HFO) nanoparticles onto different porouspolystyrene hosts, PS-, negatively charged with sulfonic acid groups, and PS0, covalently bonded neutralchloromethyl groups. Experimental results showed clear differences between HFO-PS-and HFO-PS0in theirCu uptake capabilities in the presence of sulfate. The amount of Cu adsorbed on HFO-PS0was markedlypromoted by introducing sulfate, being consistent with bulky HFO particles. As for HFO-PS-, withmonovalent cation as background (Na), it exhibited an apparent decrease in Cu adsorption as a result of thecompeting effect of Na cations and the solution complexation between Cu and sulfate ions. Contrarily, theadsorbed Cu was increased by introducing sulfate in the divalent cation background (Ca), because sulfateions were allowed to access to the loaded HFO nanoparticles due to the screening of the sulfonic acid groupscaused by Ca ions. XPS spectroscopy further demonstrated that the formation of Cu-SO4ternary complexesaccounted for the enhanced Cu sorption both on bulky HFO and hybrid HFO sorbents in the presence ofsulfate. These results indicated that effect of sulfate ligand on metal adsorption to hybrid iron oxides waslargely dependent on the surface properties of the host materials, as well as the loaded HFO.

摘要： Iron oxides are usually preloaded within nanoporous supports of large particle size to improvetheir feasibility for practical environmental remediation including arsenic and heavy metals removal, andeffect of co-ions on the performance of the resulting composites has been well investigated. However, noattempt has been made to investigate their adsorption behavior of heavy metals in the presence ofcounter-ions, such as sulfate. In this study, two hybrid sorbents (denoted as HFO-PS-and HFO-PS0respectively) were prepared by loading hydrous ferric oxide (HFO) nanoparticles onto different porouspolystyrene hosts, PS-, negatively charged with sulfonic acid groups, and PS0, covalently bonded neutralchloromethyl groups. Experimental results showed clear differences between HFO-PS-and HFO-PS0in theirCu uptake capabilities in the presence of sulfate. The amount of Cu adsorbed on HFO-PS0was markedlypromoted by introducing sulfate, being consistent with bulky HFO particles. As for HFO-PS-, withmonovalent cation as background (Na), it exhibited an apparent decrease in Cu adsorption as a result of thecompeting effect of Na cations and the solution complexation between Cu and sulfate ions. Contrarily, theadsorbed Cu was increased by introducing sulfate in the divalent cation background (Ca), because sulfateions were allowed to access to the loaded HFO nanoparticles due to the screening of the sulfonic acid groupscaused by Ca ions. XPS spectroscopy further demonstrated that the formation of Cu-SO4ternary complexesaccounted for the enhanced Cu sorption both on bulky HFO and hybrid HFO sorbents in the presence ofsulfate. These results indicated that effect of sulfate ligand on metal adsorption to hybrid iron oxides waslargely dependent on the surface properties of the host materials, as well as the loaded HFO.

摘要： Iron oxides are usually preloaded within nanoporous supports of large particle size to improvetheir feasibility for practical environmental remediation including arsenic and heavy metals removal, andeffect of co-ions on the performance of the resulting composites has been well investigated. However, noattempt has been made to investigate their adsorption behavior of heavy metals in the presence ofcounter-ions, such as sulfate. In this study, two hybrid sorbents (denoted as HFO-PS-and HFO-PS0respectively) were prepared by loading hydrous ferric oxide (HFO) nanoparticles onto different porouspolystyrene hosts, PS-, negatively charged with sulfonic acid groups, and PS0, covalently bonded neutralchloromethyl groups. Experimental results showed clear differences between HFO-PS-and HFO-PS0in theirCu uptake capabilities in the presence of sulfate. The amount of Cu adsorbed on HFO-PS0was markedlypromoted by introducing sulfate, being consistent with bulky HFO particles. As for HFO-PS-, withmonovalent cation as background (Na), it exhibited an apparent decrease in Cu adsorption as a result of thecompeting effect of Na cations and the solution complexation between Cu and sulfate ions. Contrarily, theadsorbed Cu was increased by introducing sulfate in the divalent cation background (Ca), because sulfateions were allowed to access to the loaded HFO nanoparticles due to the screening of the sulfonic acid groupscaused by Ca ions. XPS spectroscopy further demonstrated that the formation of Cu-SO4ternary complexesaccounted for the enhanced Cu sorption both on bulky HFO and hybrid HFO sorbents in the presence ofsulfate. These results indicated that effect of sulfate ligand on metal adsorption to hybrid iron oxides waslargely dependent on the surface properties of the host materials, as well as the loaded HFO.

摘要： Iron oxides are usually preloaded within nanoporous supports of large particle size to improvetheir feasibility for practical environmental remediation including arsenic and heavy metals removal, andeffect of co-ions on the performance of the resulting composites has been well investigated. However, noattempt has been made to investigate their adsorption behavior of heavy metals in the presence ofcounter-ions, such as sulfate. In this study, two hybrid sorbents (denoted as HFO-PS-and HFO-PS0respectively) were prepared by loading hydrous ferric oxide (HFO) nanoparticles onto different porouspolystyrene hosts, PS-, negatively charged with sulfonic acid groups, and PS0, covalently bonded neutralchloromethyl groups. Experimental results showed clear differences between HFO-PS-and HFO-PS0in theirCu uptake capabilities in the presence of sulfate. The amount of Cu adsorbed on HFO-PS0was markedlypromoted by introducing sulfate, being consistent with bulky HFO particles. As for HFO-PS-, withmonovalent cation as background (Na), it exhibited an apparent decrease in Cu adsorption as a result of thecompeting effect of Na cations and the solution complexation between Cu and sulfate ions. Contrarily, theadsorbed Cu was increased by introducing sulfate in the divalent cation background (Ca), because sulfateions were allowed to access to the loaded HFO nanoparticles due to the screening of the sulfonic acid groupscaused by Ca ions. XPS spectroscopy further demonstrated that the formation of Cu-SO4ternary complexesaccounted for the enhanced Cu sorption both on bulky HFO and hybrid HFO sorbents in the presence ofsulfate. These results indicated that effect of sulfate ligand on metal adsorption to hybrid iron oxides waslargely dependent on the surface properties of the host materials, as well as the loaded HFO.

摘要： Iron oxides are usually preloaded within nanoporous supports of large particle size to improvetheir feasibility for practical environmental remediation including arsenic and heavy metals removal, andeffect of co-ions on the performance of the resulting composites has been well investigated. However, noattempt has been made to investigate their adsorption behavior of heavy metals in the presence ofcounter-ions, such as sulfate. In this study, two hybrid sorbents (denoted as HFO-PS-and HFO-PS0respectively) were prepared by loading hydrous ferric oxide (HFO) nanoparticles onto different porouspolystyrene hosts, PS-, negatively charged with sulfonic acid groups, and PS0, covalently bonded neutralchloromethyl groups. Experimental results showed clear differences between HFO-PS-and HFO-PS0in theirCu uptake capabilities in the presence of sulfate. The amount of Cu adsorbed on HFO-PS0was markedlypromoted by introducing sulfate, being consistent with bulky HFO particles. As for HFO-PS-, withmonovalent cation as background (Na), it exhibited an apparent decrease in Cu adsorption as a result of thecompeting effect of Na cations and the solution complexation between Cu and sulfate ions. Contrarily, theadsorbed Cu was increased by introducing sulfate in the divalent cation background (Ca), because sulfateions were allowed to access to the loaded HFO nanoparticles due to the screening of the sulfonic acid groupscaused by Ca ions. XPS spectroscopy further demonstrated that the formation of Cu-SO4ternary complexesaccounted for the enhanced Cu sorption both on bulky HFO and hybrid HFO sorbents in the presence ofsulfate. These results indicated that effect of sulfate ligand on metal adsorption to hybrid iron oxides waslargely dependent on the surface properties of the host materials, as well as the loaded HFO.