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Green extraction of the active lignans from Schisandra chinensis has received considerable attention due to their promising applications in the biomedical field. In this study, microwave‐assisted deep eutectic solvent method was used to simultaneously extract five lignans: Schizandrol A, Schizandrol B, Schisantherin A, Schisandrin A and Schizandrin B. The extraction parameters were optimized according to the calculated comprehensive score obtained from the analytic hierarchy process combined with the entropy weight method. The optimal extraction conditions were that the molar ratio of choline chloride and glycolic acid is 4:1, water content is 30% (V/V), solid–liquid ratio is 1:20 (Wg:VmL), extraction time is 20 min, and extraction temperature is 70°C, under which the extraction rate of the five lignans were 10.89, 8.616, 4.019, 4.893, and 5.318 mg/g. These results confirmed that our extraction method is efficient and feasible for green extraction of lignans from S. chinensis. [ABSTRACT FROM AUTHOR]

Ramie composites have been widely used in automobiles, daily necessities, aerospace, ships, cruise lines, etc., but their flame retardant properties are relatively poor, which is difficult to meet the flame retardant performance requirements of composites for rail transit. In order to improve the properties of ramie reinforced composites, flame retardant treatment is necessary. In this paper, phosphorus flame retardant phytic acid (PA) was used to modify ramie fabric, and then the composites were prepared. The flame retardancy and mechanical properties of ramie reinforced composites were investigated. It was found that the flame retardancy of ramie composites was improved after flame retardant modification with phytic acid, but the mechanical properties were decreased. In order to improve the mechanical properties of PA ramie composites, two kinds of layered PA ramie/glass fiber hybrid composites were prepared by replacing part of ramie with glass fiber. The results show that the addition of glass fiber can improve the mechanical properties and flame retardancy of composites. [ABSTRACT FROM AUTHOR]

In this study, proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites were synthesized by the hydrothermal method. The prepared Fe3O4 nanocomposites were characterized by Fourier transform infrared spectrometer (FTIR), X-ray powder diffractometer (XRD), physical property measurement system (PPMS), particle size analyzer, scanning electron microscope (SEM), and transmission electron microscope (TEM). FTIR results indicated that the obtained products were coated with proanthocyanidins. The SEM and TEM results, as well as particle size distribution analysis, revealed that the obtained products were spherical particles with average diameter of 3 2 8. 6 2 ± 2 6. 7 5 nm. XRD and PPMS characterization confirmed that the Fe3O4 nanoparticles have a cubic spinel structure with magnetic properties. The performance of the Fe3O4 nanocomposites for removing organic dyes in an aqueous solution was investigated. The synthesized products were found to be effective on removing various organic dyes, such as Methylene blue (MB), neutral red (NR) and Rhodamine B (RhB), indicating their considerable potential as efficient dyes adsorbents for wastewater treatment. Proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites were synthesized by the hydrothermal method. The obtained Fe3O4 nanocomposites can efficiently remove the organic dyes in an aqueous solution. Proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites had the potential to be developed as efficient dyes adsorbents for wastewater treatment. [ABSTRACT FROM AUTHOR]

The serious damage caused to 3D braided carbon fiber (CF)/epoxy (EP) composites in high-energy irradiation environments is a pressing research topic that has not yet been reported. This study analyzed the γ-irradiation multi-scale damage of the matrix, interfaces, and near-interface regions in 3D braided CF/EP composites with three different braiding angles (18°, 28°, 38°) at atomic, microscopic, and macroscopic scales. The molecular structure and atomic charge information alterations of epoxy matrix were characterized using soft X-ray absorption spectroscopy (sXAS). When the irradiation dose reached 1000 KGy, the compressive strength of composites decreased by 20.88 %, 18.07 %, and 16.60 %, respectively, with an increase in the braiding angle. Micro-CT observation, along with statistical computing, confirmed that irradiation causes interface damage and increases the defect volume of 3D braided composites. Nanoindentation was used to compare the modulus of carbon fiber, interface, near-interface regions and matrix in irradiated composites and the function of CF/resin interface as an irradiation defect capture site in the irradiation resistance of resin-matrix composites has been newly established. In addition, the mechanism behind the effect of braiding angle on macroscopic properties was also analyzed. [Display omitted] • The braided structures exhibited varying responses to irradiation, with 3D-38° showing the highest performance retention. • Soft X-ray absorption spectrometry was developed to characterize the valence changes of oxygen and carbon in irradiated resin. • Interface as an irradiation defect capture site consumes most of the energy and reduces the damage of resin near the interface. [ABSTRACT FROM AUTHOR]

Green synthesis of Ag nanoparticles (AgNPs) by using the plant extract is a very important strategy to gain efficient antimicrobial agents with strong antimicrobial activity and low toxicity. In this study, jujube seed extract (JSE) is utilized to green synthesis of AgNPs by both hydrothermal process and solution‐based approaches. UV–vis absorption spectroscopy and infrared spectroscopy (FTIR) spectra confirm that jujube seed extract functionalized Ag nanoparticles are formed by both approaches and jujube seed extract covered on the surface of Ag nanoparticles. Transmission electron microscopy (TEM) images indicate that the JSE‐AgNPs are spherical with the average diameter of 17.7 and 14.2 nm for the hydrothermal process and solution‐based approaches, respectively. X‐ray diffraction (XRD) results indicate that the JSE‐AgNPs prepared by both approaches have face‐centered cubic crystal structure. The antimicrobial activity test reveals that minimum inhibitory concentrations (MIC) of JSE‐AgNPs by the solution‐based method are 62.5, 125, and 62.5 µg mL−1 against Escherichia coli, Staphylococcus aureus, and Candida albicans, respectively. These results imply that the JSE‐AgNPs have potential to be developed as efficient antimicrobial agents. [ABSTRACT FROM AUTHOR]

Three-dimensional braided composite materials have been widely applied to engineering structure manufacturing. It is of a great importance to characterize the impact damage of the three-dimensional braided composite under various temperatures for optimizing the engineering structure. Here we conducted transverse impact deformation and damage of three-dimensional braided composite beams with different braiding angles at room and elevated temperatures. A split Hopkinson pressure bar with a heating device combined with high-speed camera was employed to test multiple transverse impact behaviors and to record the impact deformation developments. The results indicated that failure load, initial modulus, and energy absorption decreased with the increase of temperature, whereas the deformation increased slightly with elevated temperatures. We found that the impact brittle damages occurred earlier and the local adiabatic temperature raised higher when the temperature is lower than the glass transition temperature (Tg) of epoxy resin. While above the Tg, the impact ductile damages occurred later and the local temperature raised lower. The thermal stress distribution along the braiding yarn leads to cracks propagation in yarn direction. Part of the impact energy absorptions converted into thermal energy. In addition, the beam with larger braiding angle has high damage tolerance and crack propagation resistance. [ABSTRACT FROM AUTHOR]

Fracture behaviors of three-dimensional braided composites could be designed from braided preform structures. Here, we compare the fracture behaviors of three-dimensional four direction (3D4d) and five directional (3D5d) braided composites under impact loading. A drop weight impact tester combined with a high-speed photography system was employed to characterize the progressive damages and fracture behaviors, which include crack growth and crack mouth opening displacement. The two-dimensional digital image correlation method was utilized for evaluating deformation contours and strain field. A finite element analyses model was established to reveal impact damage evolution, crack growth, stress distribution, and energy absorption at microstructure level. We found that axial yarns had great effect on the crack propagation paths. The stress at the notch bottom caused yarn breakage and then resulted in a sharply growing crack. The axial yarns in the 3D5d braided composites impede the progress of cracks under transverse impact. The 3D5d braided composites have smaller crack mouth opening displacement than that of the 3D4d composites. The braided preform is the main energy absorption component. With the same volume fraction, axial yarns exhibit the highest energy absorption. Due to the existence of axial yarns, the resistance to the fracture and crack growth of the 3D5d braided composites is better than the 3D4d braided composites. [ABSTRACT FROM AUTHOR]

Magnetic anisotropy is an important character for magnetic materials. In this work, magnetic anisotropy of (110)-oriented ferrimagnetic NiCo2O4 (NCO) thin films deposited epitaxially on MgAl2O4 substrates by pulsed laser deposition is studied and compared with (001)-oriented NCO films. While the (001)-oriented films show a perpendicular magnetic anisotropy with the out-of-plane [001] direction as the magnetic easy axis, a jump in magnetic hysteresis loop is observed for the (110)-oriented films with a field applied vertically along the out-of-plane [110] direction. This jump in hysteresis loop is associated with a spin reorientation transition, depending on the applied field and temperature. Magnetic force microscopy reveals that this spin reorientation develops as domains nucleate, grow, and coalesce. This spin reorientation transition is discussed in terms of the competition between different magnetic anisotropy in an external field. [ABSTRACT FROM AUTHOR]

Abstract The understanding of dynamic damage and failure of thermo-oxidative aged 3D carbon fiber/epoxy braided composite is critical to its durability design. Here we aim at a fine description of damage and failure of aged composites under impact compression by means of experiment and finite element analysis (FEA). The composites and epoxy resins were aged in air at 110 °C, 130 °C and 150 °C for prescribed time, respectively. The failure processes were recorded with high-speed camera. We found that with the increase of ageing temperature, the interface damage becomes more serious and the epoxy resins tend to a rubbery behavior. For the composites aged at lower temperature (110 °C), the impact resistance degradation is mainly attributed to the degradation of epoxy resin. While interface degradation is found to be the dominant degradation mechanism when the composites aged at higher temperature (130 °C, 150 °C). FEA results showed that in the process of impact, the plastic deformation induced temperature and thermal stress of the aged composites decrease compared with the unaged composite. For the unaged composites and the composites aged at lower temperature, the damage of reins is the main factor that affects the energy absorption of fiber tows. The interface damage plays a more important role in the energy absorption of fiber tows when the composites aged at higher temperature. [ABSTRACT FROM AUTHOR]

Impact fracture behaviors of three-dimensional braided composites are critical to designing the braided composite parts. Here we report the impact fracture behaviors of three-dimensional braided composite U-notch beam tested on a modified split Hopkinson pressure bar. Crack mouth opening displacement, deformation process, and crack evolutions were recorded with high-speed photography camera. The digital image correlation method was used to calculate deformation contours of the braided composite. A microstructure model of the three-dimensional braided composite U-notch beam was established for analyzing damage evolution and fracture mechanisms. The histories of deformation, the load, and the crack mouth opening displacement were obtained from the impact fracture test and finite element analysis. It was found that the impact fracture resistance and morphologies were influenced by the braided structure and braided yarn orientations. The crack generated at the notch tip and then propagated along the braided angle direction rather than the perpendicular direction that often occurred for isotropic materials, such as the epoxy resin solid. The combinations of different braided angle and yarns are recommended for high impact fracture behavior design. [ABSTRACT FROM AUTHOR]

Thermal stress and thermomechanical coupling behaviors are essential to design 3D braided composite materials under impact loading. Here we report the thermal/mechanical coupling properties of 3D carbon fiber/epoxy matrix braided composite under impact compressions. The compressive behaviors of the 3D braided composites with different braiding angles have been tested. A high-speed camera system was used to capture the compressive deformation and damage developments. Two material models described as “with thermal parameter (WT) model” and “without thermal parameter (NT) model” were established to calculate thermal stress induced from impact compression. Both the two models give reasonable predictions. The plastic deformation energy of the composite is found to increase with braiding angle, resulting in higher temperature and greater thermal stress. The difference between the stress curves obtained from two models increases with the increase in braiding angle. Although the effect of thermal stress on the stress-strain curve obtained from two models is not obvious for the composite with smaller braided angle, the stress level of the resin and fiber tows of the WT model is higher than that of the NT model. The resin of the WT model has damages earlier and more serious. Likewise, the interface damage is also more serious. [ABSTRACT FROM AUTHOR]

The growth of unique two-dimensional nanosheets on hollow and porous metal sulfides has received significant attention in adsorption and catalysis applications. Herein, we report a facile strategy to grow ultrathin nanosheets (NSs) on Cu 7 S 4 nanotubes (NTs) via a two-step process (Cu 7 S 4 -NS-T). First, the obtained Cu nanowires (NWs) are oxidized in a hydrogen peroxide solution to form Cu@CuO composite nanowires decorated with ultrathin CuO NSs. Then, Cu 7 S 4 -NS-T composed of Cu 7 S 4 NTs and Cu 7 S 4 NSs is obtained from Cu@CuO NWs via a sulfurization process with the Kirkendall effect, in which anion-exchange reaction between Cu@CuO and S2‐− anions resulted in the formation of hollow structure. Due to fuse porous nanotubes and ultrathin nanosheets with abundant exposed copper centers, the obtained Cu 7 S 4 -NS-T shows extraordinary adsorption ability for the removal of anionic dyes, such as Congo red (CR) with a maximum adsorption capacity of 1166.07 mg/g, much superior to that of commercial activated carbon. Adsorption equilibrium and kinetic studies indicate that chemisorption is the main control process for the enrichment of the anionic dyes. The Cu 7 S 4 -NS-T can be used as a novel effective adsorbent for rapidly and efficiently removing dyes contaminants in water. [Display omitted] • Cu 7 S 4 -NS-T and Cu@CuO NWs were obtained from pure Cu NWs after their oxidation and sulfurization process, respectively. • Formation of hierarchical structures composed of hollow Cu 7 S 4 NWs decorated with Cu 7 S 4 NSs • The Cu 7 S 4 -NS-T presents excellent adsorption for anionic dye, compared to activated carbon materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • DOX&ICG@H-ZIF-8@CaCO 3 -PEG NPs very high drug loading due to hollow structure. • π-π stacking effect of ICG and DOX increases drug stability. • The system has shown synergistic effects of pH sensitivity, photothermal, and calcium overload synergistic effects in vitro. In this study, we synthesized DOX-loaded H-ZIF-8@CaCO 3 -PEG nanocarrier, which combined with calcium overload and photothermal therapy (PTT) for synergistic therapy. The nanocarrier comprised a PEG modified calcium carbonate (CaCO 3) shell and a hollow imidazolate zeolite skeleton (H-ZIF-8) core, in which the chemotherapy drug doxorubicin hydrochloride (DOX) and photosensitizer indocyanine green (ICG) were simultaneously co-loaded. In vitro cellular experiments revealed that the lethality of DOX&ICG@H-ZIF-8@CaCO 3 -PEG against tumor cells was significantly higher than that of the single chemotherapy owing to the combination with chemotherapy and photothermal therapy as well as calcium overloading. This drug-loaded nanocarrier exhibits notable characteristics such as exceptional stability, elevated drug loading capacity and efficient release of the loaded drug, which provides a promising perspective for efficient synergistic therapy. [ABSTRACT FROM AUTHOR]

We proposed a thermo-mechanical coupled model to better understand the coupling effects of thermo-oxidative aging and braiding structure on the high-speed impact responses of 3D braided carbon fiber reinforced epoxy composite. The impact responses of the aged and unaged braided composites with different braiding structures were experimentally and numerically investigated. We found that both thermo-oxidative aging and braiding structure have a significant influence on the impact responses of braided composites, and they also affect each other. Stress, adiabatic temperature rise, thermal strain and thermal stress of composites will decrease after aging, while increase with the increase of braiding angle. Increasing the braiding angle of the braided composite can effectively reduce the effect of thermo-oxidative aging on the impact responses. When the braiding angle is 42, the mechanical properties and damage of the composites are almost unaffected by thermo-oxidative aging, but the thermal stress in the impact process decreases significantly after aging. • The coupling effects of braiding structure and thermo-oxidative aging on the high-speed impact responses were experimentally and numerically investigated. • Stress, adiabatic temperature rise, thermal strain and thermal stress of composites will decrease after aging, while increase with the increase of braiding angle. • Increasing the braiding angle of the braided composite can effectively reduce the effect of thermo-oxidative aging on the impact responses. [ABSTRACT FROM AUTHOR]

A composite material with improved characteristics can be produced by combining metal‐organic frameworks (MOFs) with polymer fibers. In contrast to commonly used powdered MOFs, polymer fibers can offer flexible support for MOFs, and some of the fibers can even work in concert with MOFs. The molecular transport channels are significantly enlarged when polymer fibers are employed as the base material for composites rather than conventional polymer films and mixed matrix films. This makes it simpler for the molecules to bind to the active site, speeding up the reaction. First, a brief analysis of the binding of MOFs to fibers is provided, followed by a systematic summary of the MOF forming process, including the synthesis and modification of MOFs, which lays the foundation for the subsequent summary of the synthesis methods of MOFs–fiber composites. In this article, three strategies are presented for attaching MOFs to polymer fibers: cospinning MOFs with fibers, depositing MOFs on fiber surfaces, and in situ growing MOFs on fiber surfaces. Different binding techniques make MOFs–fiber composites promising for many applications. Finally, the improvement of MOFs–fiber composites and their possible application scope are discussed. [ABSTRACT FROM AUTHOR]

Highlights • Multiscale geometrical model of 3D braided composite was established. • Thermal behavior and surface crack of epoxy resin after ageing were characterized. • Impact fracture behaviors were compared after different ageing time. • Ageing mechanisms were analyzed at multiscale geometrical levels. Abstract Fracture behaviors of thermo-oxidative aged 3D braided composites are significantly affected by interfacial weakening and matrix degradation. Here we report the impact fracture behaviors of three-dimensional four direction (3D4d) and five directional (3D5d) braided composites under thermo-oxidative conditions. Specimens were exposed at hot air (180°C) for 2, 4, 8 and 16 days, respectively. The oxidation-induced crack widths in aged specimen surface were observed and analyzed. The impact fracture behaviors and damage evolutions of braided specimens were recorded with high-speed camera. Based on the test results, we established a multi-scale finite element analyses (FEA) model to reveal interface failure, stress distribution and energy absorption of virgin and aged specimens at microstructure level. The impact fracture behaviors of both different braided composites continuously decreased with increasing ageing time. The matrix degradation and interfacial weakening are main degradation mechanisms. In addition, the FEA results show that the impact fracture properties significantly depend on the braided structures. The braided preform is the main energy absorption component and the axial yarns contribute the highest energy absorption capacity. With the insertion of axial yarns, the 3D5d braided composites exhibit a better fracture resistance after thermo-oxidative ageing. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract When serving as a lightweight structural member in many areas, the dynamic mechanical behavior of fiber-reinforced polymeric matrix composites, especially under different strain rates, means a lot to the optimization of structure design as to high-speed impact. Under different loading rates and directions, we experimentally and numerically investigated the strain rate effect on the impact compressive behavior of 3-D angle-interlock woven composites (3-D AWCs) composed of carbon fiber and epoxy resin. Based on the factual geometrical architecture of 3-D AWC, the meso-scale model, which considers the interfacial damage between the reinforcements and matrix, was established to visually characterize the deformation history and damage morphologies of 3-D AWCs during impact compression process. Further, we performed high strain rate compressive tests on the split Hopkinson pressure bar (SHPB) apparatus integrated with a high-speed photography system for capturing images of progressive damage process to validate the proposed mesoscopic model. The stress-strain curves of various strain rates show strain rate effect varies depending on loading direction. The rate sensitivity on the compressive failure strength exists at weft direction and through-thickness direction except for warp direction. Moreover, both from images and finite element model results, the localized adiabatic shear band induced by intense plastic strain, initiates mainly from epoxy resin matrix and propagates along the interface at all three loading directions. [ABSTRACT FROM AUTHOR]

To improve the spray fire extinguishing performance of magnesium-hydroxide gel dry-water powder, this paper studied the preparation speed, material mass ratio, fluidity, bulk density, pressure resistance, and fire extinguishing performances of modified dry-water powders. A pure-water dry-water powder was modified by applying an effective extinguishing component, magnesium hydroxide, and a coagulant, Gellan gum. The preparation process parameters of the pure-water dry-water powder system were optimized. The results showed that the optimal process parameters for the preparation of dry-water powder were a rotation speed of 4000 rpm, an SiO 2 :H 2 O ratio of 9:100, and a stirring time of 3 min. The resting angle of magnesium-hydroxide gel dry-water powder was below 28°, with good fluidity. The bulk density of the dry-water powder was lower than that of the BC-class dry powder extinguishing agent, and the bulk density of the magnesium-hydroxide gel dry-water powder was 0.467 g·mL−1. With the increase in pressure, the damage rate of the dry-water powder increased. The addition of magnesium hydroxide and Gellan gum significantly improved the pressure resistance of the dry-water powder. At a pressure of 1.4 MPa, the magnesium-hydroxide gel dry-water powder was only 11% damaged. The performance of the magnesium-hydroxide gel dry-water powder was improved by 37.21% compared with the average cooling rate of the BC-class dry powder extinguishing agent used as a control fire extinguishing group. The dry-water powders produced by modifying the dry-water powders with magnesium hydroxide and Gellan gum could withstand higher driving pressures, and they had improved powder diffusion, reduced powder charge volume, and increased fire extinguishing properties compared with those of the other dry-water powders. [Display omitted] • Modifying dry-water powder allows it to obtain new and improved properties. • A new gel dry-water powder was produced using magnesium hydroxide and Gellan gum. • Spraying and extinguishing tests were conducted on the new dry-water powder. • The new gel dry-water powder was 37.21% more efficient than BC-class dry powder. [ABSTRACT FROM AUTHOR]

• Modified metal-organic framwork are applied to improve the radiation resistance of epoxy resins and investigate the anti irradiation mechanism of metal-organic framework. • UIO-66-OH nanoparticles can effectively improve the tensile modulus and thermal stability of epoxy resin. • 88.7% reduction in free radical concentration of UIO-66-OH / EP composite compared to epoxy resin. Understanding the degradation mechanism of epoxy resin under irradiation and enhancing the radiation resistance of epoxy resin are of great significance for its application in aerospace and nuclear industries. In this study, we investigated the radiation resistance of epoxy reinforced by UIO-66-OH metal-organic framework. Outstanding radiation resistance was achieved by using UIO-66-OH nanoparticles as radical scavengers to retard epoxy degradation. The introduction of UIO-66-OH reduces the content of free radicals generated after irradiation by 88.17%. UIO-66-OH also improves the mechanical and thermal properties of epoxy before and after irradiation. The scavenging radicals mechanism of hydrogen atom transfer of UIO-66-OH is more dominant than that of graphene oxide and carbon nanotubes. The radiation resistance of UIO-66-OH nanoparticles is related to hydroxyl functionalization and porous structure. This work provides a new idea and method for improving the stability of epoxy resin under gamma ray radiation. [ABSTRACT FROM AUTHOR]

Nonuniform Li+ flux and lithiophilic sites cause uneven lithium deposition, which impedes the application of lithium metal batteries. Herein, a reduced graphene oxide (rGO)/Ti3C2Tx lattice with periodic printed holes is fabricated by 3D printing. Mesoporous structures formed by regularly assembled nanosheets provide abundant lithiophilic sites. The Li+ flux is regulated by the periodic printed holes prepared by 3D printing. The deposition of lithium is homogenized by the synergistic effect of uniform Li+ flux and abundant lithiophilic sites. The resultant 3D‐printed Li anode has excellent cycling stability up to 3000 h and a high average Coulombic efficiency of 98% after a long lifespan of ≈1000 h. Our work highlights the effect of the correlation between macroscopic and microscopic pores formed by 3D printing on inhibiting lithium dendrites, providing a novel pathway for highly 3D‐printed stable lithium metal anode. [ABSTRACT FROM AUTHOR]

Textile technology offers a plethora of design and production alternatives for composite reinforcements. In this study, highly aligned continuous hemp tape was produced based on hemp sliver and used to prepare unidirectional composites with optimized mechanical properties. The fiber content, preform areal density, and fiber orientation were considered to investigate the mechanical properties of the composite. The areal density of the hemp tape felt was contingent on the hemp sliver drafting multiple. Both composite tensile and flexural strength reached the maximum of 166.85 MPa and 207.68 MPa at drafting multiple i=2 and 30% fiber content, which were comparable with those reported for hemp fiber composites. The hemp tape was favorable for more complex shapes for applications. The superior mechanical properties and discrimination between the composites enhanced with two typical orthogonal reinforcement diversified the application potential in the field of automotive, furniture and architectural panels. • Hemp tape with highly aligned fibers was produced by self-designed equipment. • Low tape areal density aids fiber alignment accompanied with delamination risk. • Hemp tape-based composite properties are not proportional to fiber orientation. [ABSTRACT FROM AUTHOR]

The silanized graphene oxide (KH-GO) with different mass fractions was dispersed in epoxy resin by a solution blending method and resin transfer molding process. The nano indentation method was used to test the micromechanical properties of GO/epoxy composites with different mass fractions, and the effect of GO on the hardness of epoxy matrix composites was quantitatively determined, and the influence of adding KH-GO on the thermal mechanical and bending properties of epoxy resin was discussed by dynamic thermal mechanical and universal strength machine tests. The experimental results show that the thermal and mechanical properties of composites are improved with the increase of the amount of KH-GO. Especially, when the content of KH-GO was 0.3%, the bending strength (125.4 MPa), hardness (281.0 MPa), and glass transition temperature (99.6°C) of composites reached the highest. It was proved that the composites showed its excellent performance and the silane coupling agent was successfully grafted to the graphene oxide by covalent bond, which effectively improved the interface compatibility of the reinforcing body and the matrix and was related to good dispersibility in the epoxy resin. This method is simple and effective, providing a certain reference value for the enhancement of the mechanical properties of the next generation of nanocomposites. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) membranes with doorman characteristic, tunable nanochannel microenvironment and high interfacial adhesion were fabricated. Herein, polyethyleneimine (PEI) molecules were selected for bridging, reducing and intercalating the GO nanosheets in GO-PEI membranes. Moreover, the optimal amount of PEI molecules facilitated the expansion and alignment of the transfer channels with the spacing of 0.93 nm to 1.52 nm. In particular, the GO nanosheets undertook deoxidations twice under the action of a strong alkaline NaOH solution and PEI molecules, which led to more structural defects and certain wrinkles for providing extra water transfer channels. On this basis, PEI molecules exhibited doorman characteristics at different pH values. As the state-of-the-art technology, the nano-scratch tests showed that the interfacial adhesion of the GO-PEI membrane (18.62 μN) bridged by PEI was nearly 9 times stronger than that of the pure GO membrane (2.15 μN). [ABSTRACT FROM AUTHOR]

[Display omitted] Core-shell structure has been receiving extensive attention to enhance the electromagnetic wave (EMW) absorption performance due to its unique interface effect. In this paper, a micro-flower like ZnCo@C@1T-2H-MoS 2 was prepared through MOF self-template method. The introduction 1T-2H-MoS 2 shell helps optimize impedance matching of the CoZn@C particles to improve the EMW absorption ability. The minimal reflection loss (RL min) value of ZnCo@C@1T-2H-MoS 2 is −35.83 dB with a thickness of 5.0 mm at 5.83 GHz and the effective absorption (RL < -10 dB) bandwidth up to 4.56 GHz at 2.0 mm thickness. Meanwhile, the overall effective absorption bandwidth (OEAB) can reach up to 13.44 GHz from 4.56 to 18.0 GHz. Moreover, ultrafast photothermal performances are also achieved, which can guarantee the normal functioning of ZnCo@C@1T-2H-MoS 2 materials in cold conditions. The excellent EMW absorption and photothermal performance are attributed to the unique structure designed with the core of magnetic ZnCo@C rhombic dodecahedral and the shell of dielectric micro-flower like 1T-2H-MoS 2 optimize impedance matching. [ABSTRACT FROM AUTHOR]

• A virtual fiber model for multilayer biaxial weft knitted (MBWK) fabric is built for simulating the in-plane shear performance. • The shear angle distribution due to unique MBWK structure is revealed. • The interaction between the deformation of stitch and the rearrangement of axial yarn is evaluated in depth. The multilayer biaxial weft knitted (MBWK) fabrics and their composites have been widely applied in fields of complex structural products due to their flexible curved deformability. The existence of stitch in MBWK complicates the deformation behavior under the in-plane shear loading. However, it has not been well explored and understood. In this study, a numerical micro-scale virtual fiber modeling was built to investigate the in-plane shear performance of MBWK by considering the micro geometric features and fiber property that are difficult to be characterized solely by experiment. The strain conditions of the stitch that determine the fabric shear behavior are discussed. The deformation behavior leads to local deformation and morphological locking of the stitch. In the early stage of the shearing, the deformability of stitch provides enough space to accommodate the rearrangement of axial yarns. In the shear locking stage, the restriction of stitch and compression within axial yarns at high shear angles restricts the axial yarns from movement in the loading direction. When the theoretical shear angle is 20°, the shear angle located in different shear regions varies. The maximum shear angle near the loading area is 19.1°, while the minimum shear angle near the fixed area is approximately 17°. The results illustrate the deformation mechanism of MBWK under in-plane shearing and provide an excellent guidance for the design of large deformation fabrics, especially for curved surfaces, thus realize the effective utilization of fabrics in engineering applications. [ABSTRACT FROM AUTHOR]

Water pollution has caused serious water shortage, and this trend becomes increasingly serious in the world. Therefore, how to efficiently access water resources is crucial for human beings. Considering the easy blockage problem of traditional fog-harvesting mesh, we used the fog catcher brushes structure to avoid the problem effectively. Besides, most of the modified coatings on fog-harvesting materials contain fluorosilane, which is expensive, harmful and unstable for a long time using. In addition to the general properties of dimethyl silicone oil, hydrogen methyl silicone oil can participate in a variety of chemical reactions and have a good film-forming performance due to its molecular structure containing active Si–H keys compared to the similar studies about the oil-infused coating. Besides, the low contact angle hysteresis of the droplet can benefit for the droplet sliding off the surface, which further improve the fog-harvesting efficiency. In this paper, mechanical cutting method, water bath method, and spray coating method were successfully combined to construct slippery "fog catcher brushes" with alumina micro-needle structured surfaces from micro control to macro design. Furthermore, the effect of wettability, pattern shape and pattern size on fog-harvesting performance were investigated. Experiment results indicated that slippery surface benefited for the fog deposition and transportation compared with the superhydrophilic and plain surface. When the fog droplets passed through the sample with 10-teeth arc-shaped pattern, it would fully contact the surface, and only a small amount of fog droplets escaped from the surface. With the adjacent droplets coalescing, the droplets slided off along both sides of the pattern, then the contact surface decreased gradually from the top to the bottom, so droplets could transport rapidly. Analysis demonstrated that the slippery arc-shaped fog catcher brushes with 10-teeth had a good effect on the capturing and transporting of fog droplets, which offered a way to rationally construct materials with enhanced fog-harvesting performance from micro control to macro design. In this study, bioinspired from the cactus-inspired special geometry structure and nephenthes-inspired slippery surface, the fog catcher brushes have been prepared by the cut method and water bath method. Integrating the macro pattern design with the micro structure control, the fog-harvesting materials with different parameters were fabricated. Results of the fog harvesting performance indicated that the arc shape sample with 10-teeth showed the best fog-harvesting performance after wettability modification. [Display omitted] • Bio-inspired from the cactus special geometry and nephenthes slippery surface. • The fabrication is a simple method combined with the cutting and water bathing process. • PMHS coating has a stable contact angle hysteresis and environment friendly property. • The slippery arc shape sample with small size shows the best fog-harvesting efficiency. [ABSTRACT FROM AUTHOR]

Building reinforcement projects are designed to meet the requirements of modern sustainable development. However, the weak bonding performance of continuous glass fiber textiles to mortar presents a challenge in the manufacturing of GTRM composites, hindering their development and application. In this study, the gradient composite design technique was used to modify the interface transition zone between continuous glass fiber textile and mortar by introducing epoxy resin. This successfully resolved the issue of poor bonding between the continuous glass fiber textile and mortar interface, and promoted effective stress transfer between the two materials. The GTRM composites with an interfacial gradient structure exhibit excellent mechanical properties, including a tensile strength of 8 MPa and an interfacial shear force exceeding 27 KN. In addition, digital image correlation (DIC) was utilized to investigate the growth and development of cracks in GTRM composites, and the failure mechanism of tensile and interfacial shear tests was analyzed. Finally, the externally bonded GTRM composites were subjected to a three-point bending test, which demonstrated a significant improvement in the flexural strength and crack resistance of concrete beams. [ABSTRACT FROM AUTHOR]

For decades, single fiber reinforced composites exhibited defects of low damage tolerance resulting from brittle failure mode, which limits their further application. Therefore, hybrid composites are emerging as a new research hotspot. In this work, three-dimensional five-direction hybrid braided composites composed of different configurations of carbon and aramid yarn was manufactured. The short beam shear experiments and full-size mesoscale numerical simulation based on real braided structure computed by computed tomography (CT) image were established to investigate the hybrid effect and progressive damage process of composite. Studies have shown that neat carbon composites display the characteristics of brittle fracture, and hybrid composites demonstrate a remarkably toughening effect. The KaCb (CaKb) sample displays a 102.0% (58.7%) greater failure displacement than neat carbon composite under transverse (longitudinal) loading. Through the increasing bending deformation, the damage mode transforms to a ductile failure. The stress localization in the loaded area is retarded, and the synergistic load-bearing capacity of axial and braiding yarn is improved. This work reveals the synergistic bearing mechanism and progressive damage process of multicomponent composites with complex textile structures, which provides a theoretical basis for designing more types of hybrid composite. [ABSTRACT FROM AUTHOR]

The steel fiber textile overcomes mostly the shortcomings of traditional reinforcement materials. However, the poor corrosion resistance severely limits service life. In this study, based on the mechanism of stress corrosion and electrochemical corrosion, the epoxy resin anti-corrosion coating was designed and prepared. First, the von Mises stress distribution of lamellar and spherical fillers in epoxy resin was studied by finite element simulation, which confirmed that the stress distribution of spherical SiO 2 filler was more uniform when it was stressed. In addition, to optimize the dispersion of spherical SiO 2 in epoxy resin, the spherical polyaniline@SiO 2 (PANI@SiO 2) composites with core-shell structure were produced with in situ polymerization method. Ultrasonic C scanning results showed that the addition of PANI@SiO 2 nano-filler can effectively reduce the defects in epoxy resin. Compared with bare steel fiber, the composites coating of 2 wt% PANI@SiO 2 /epoxy showed the most excellent resistance to stress corrosion and electrochemical corrosion. The capacitance diameter is two orders of magnitude higher, which has good stability in simulated concrete pore solution. This is due to the fact that the addition of PANI@SiO 2 nanomaterials improves the physical shielding properties of epoxy, creating a labyrinth effect, and that PANI can produce passivation on the metal surface. • The finite element results showed that the spherical filler could improve the stress corrosion resistance of the epoxy composite coating. • Spherical PANI@SiO 2 composites with core-shell structure were successfully prepared, and the coating rate of PANI reached 21.04 %. • The addition of PANI@SiO 2 nanofillers could effectively reduce the defects in the epoxy resin. • The impedance spectrum of the 2 wt% PANI@SiO 2 /EP anticorrosive coating was 6 × 105 Ω/cm2 and showed good stability. [ABSTRACT FROM AUTHOR]

• Stress-strain curves and crack development of TRM composites under tension exhibit four stages. • The fiber bundle configurations of reinforced textiles are the main factors affecting the tensile failure mechanism of TRM composites. • Factors influencing the interfacial bonding response in double-lap shear tests are explored. The purpose of this paper is to study tensile properties and interfacial bonding properties of textile reinforced mortar composites (TRM) widely used for externally strengthening damaged buildings. Based on the digital image correlation (DIC) method and finite element (FE) simulation, the tensile and interfacial shear test results of steel fiber textile and carbon fiber textile reinforced mortar composites were analyzed. First, DIC was used to detect the crack onset and propagation of the specimen during the tensile process. The concept of gradient interface was introduced to improve the bonding performance. The effects of the hydration degree of mortar, and reinforcing textile type on interfacial bonding properties were then evaluated through double-lap shear testing. Last, the stress distribution and load transfer during textile pull-out from the mortar were analyzed based on FE simulation with the bond-slip law extracted from the double-lap shear experiment. [ABSTRACT FROM AUTHOR]

Some special electronic equipment not only need to avoid the interference of external electromagnetic waves (EMWs), but also need to transmit effective signals. Therefore, the development of directional electromagnetic interference (EMI) shielding materials has a great prospect. The asymmetric structure, consisting of the porous magentic rGF (reduced graphene oxide and Fe 3 O 4) layer and the dense electrical conductivity rGM (reduced graphene oxide and MXene) layer, was constructed by dual-needle 3D printing technology. After encapsulation and curing with polydimethylsiloxane (PDMS), the rGF/rGM/PDMS composites were prepared. When the ratio of rGF and rGM layers is 6:4, the SE values of rGF-6/rGM-4/PDMS composites are 38.75 dB and 30.79 dB respectively when EMWs are incident on the rGF layer and rGM layer respectively, and the ΔSE of which is about 8 dB. The results showed that the asymmetric structure composed of porous magnetic layer and dense deeply electric conductive layer could generate a special process of "weak reflection-absorption-strong reflection-reabsorption" for incident EMW. At the same time, the simulation results of the waveguide method validated the experimental results, and further explained the directional EMI shielding mechanism of asymmetric structure. For the first time, this work designs an asymmetric structure based on the double needle 3D printing technology, which provides useful inspiration for the structural design and potential application of directional EMI shielding materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Traditional polyamide nanofiltration membranes often can't obtain ideal ion selectivity due to their wide pore size distribution. In this work, a β-cyclodextrin modified sodium hyaluronate (HA-CD) was introduced to achieve the dragging effect of piperazine by non-specific hydrogen bond interaction between HA-CD and substrate and piperazine, thus realizing the purpose of sustained release of piperazine. The MD simulation results demonstrated that the diffusion rate of piperazine was reduced by approximately two orders of magnitude due to the interaction effect. In addition to making the polyamide layer thinner and smoother, HA-CD also narrows the pore size distribution. The salt filtration test showed that the prepared membrane has excellent anion selectivity (α max :114) and permeability (10.66 L m−2 h−1 bar−1). Long-term filtration and nano-scratch test results demonstrated that the prepared membranes have good operational stability (the permeability only decreased about 30%) and mechanical strength (the interface bonding strength increased about 270%). By exploring the effect of the interaction between HA-CD and substrate and piperazine on the interfacial polymerization process, which proved the feasibility of realizing high permeability selectivity and stability of the membrane by constructing the functional bridge between substrates and aqueous monomers. [Display omitted] • Slowing down the diffusion rate of piperazine by dragging effect. • Narrow pore size distribution achieved by the ordered interfacial polymerization reaction. • Grazing-incidence small-angle X-ray scattering for characterization of membrane pore structure. • Polyamide nanofiltration membranes with ultra-high mono- and divalent ion selectivity. • The improved polyamide nanofiltration membrane with excellent stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Membranes based on cyclodextrins for water treatment. • The main design ideas of membranes based on cyclodextrins. • Selective separation of membranes based on cyclodextrins. • Mechanism of optimizing membrane performance by cyclodextrins. • The current application status of membranes based on cyclodextrins. Cyclodextrins (CDs) can achieve precise separation of molecules and ions at the same time as well as improve the permeability of the membranes due to their special cavity structure and amphipathic. This paper reviewed the application advantages and challenges of CD-based membranes in dye and salt separation, organic solvent nanofiltration, pollutants removal, etc in the past ten years, focusing on the design and fabrication methods of CD-based membranes and the improvement mechanisms of membrane performance. Understanding these mechanisms has important guiding significance for the design of CD-based membranes in the future. Finally, the future trend of CD-based membranes has been prospected. Although the properties of CDs for precise molecular recognition have achieved preliminary results, CDs did not significantly enhance the permeability of the membranes. Therefore, the directional arrangement of the CDs cavity and the cavity of CDs as the main mass transfer channel will greatly boost the selectivity and permeability of the membranes in future research. [ABSTRACT FROM AUTHOR]

The limitation of plant fiber length can be overcome by using staple spinning to achieve continuity on short fibers. Ramie fiber staple yarn reinforced unsaturated polyester composites (RSYCs) were fabricated with ramie fiber and unsaturated polyester matrix. The unique fiber packing density of staple yarn must be tackled first to reflect the structure of RSYCs. The relationship between fiber packing density of staple yarn and fiber volume fraction of composite was evaluated to investigate the effect of fiber packing density on properties and predict the tensile strength of RSYCs using the rule of mixture. A scanning electron microscope illustrated fiber packing density of staple yarn. When the twist factor was 380 with the optimal yarn count of 80 tex, the fiber packing density was 19.9% higher than that at 260. Compared with the minimum tensile strength of RSYCs at 120 tex, the maximum of RSYCs at 380 was 399.2 MPa, improved by 238.6%. Measured by dynamic mechanical analysis, the viscoelastic rigidity and damping property of RSYCs was the best at 380, with the storage modulus of 31.9 GPa at 40 °C and the tan delta of 0.1226 at 80.59 °C. Compared with the neat resin and ramie fiber, the onset temperature of weight loss of RSYCs tested by thermogravimetric was reduced. The increasing fiber packing density significantly reduced the resin permeability of RSYCs, according to the contact angle and ultrasonic nondestructive testing results. There is no doubt that the obtained fiber packing density possessed great potential for promoting the development of RSYCs. [Display omitted] • Fiber packing density adjusted by yarn count and twist factor. • Fiber packing density influenced the tensile properties of ramie fiber staple yarn reinforced composites. • Fiber packing density overruled fiber volume fraction to improve the rule of mixture. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOFs were grown on the polypropylene fibers by the in-situ growth method. • Nano-sized MOFs have been synthesized to enhance the capture of PM particles. • Under the sonication of 600W, 80% of the MOFs were still loaded on the fibers. Air pollution, especially solid particulate pollution, seriously endangers people's physical and mental health. As a result, the performance and stability of air filtration membranes are increasingly required. In this work, the nano-sized (sizes < 100 nm) polypropylene@zeolitic imidazolate framework-8 (PP@ZIF-8) membranes and polypropylene@copper(II) benzene-1,3,5-tricarboxylate (PP@Cu-BTC) membranes were designed in an in-situ growth method. These membranes can achieve efficient and stable filtration of PM2.5 particles in a practical environment. The PM1.0 quality factor and filtration efficiency of PP@Cu-BTC increased by 49.28% and 58.04%, respectively, compared to the PP membrane. In addition, more than 87% of metal–organic frameworks (MOFs) particles are still fixed on the fiber after ultrasonic treatment with ultrasonic power of 600 W for 30 min. Moreover, the membranes are recyclable and have excellent water resistance (>74.5% against PM1.0 after five washing cycles) and outstanding long-term storage performance (>94.9% against PM1.0 after storage for one month). This PP@MOFs membrane provides another idea for building stable and efficient air filtration membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The latest advances of polyurethane/graphene composites including their properties and challenges in the fields of thermal conduction and flame-retardance, antimicrobial, ultraviolet resistance, electromagnetic interference shielding, and oil–water separation are widely presented. • The preparation process, applications and prospects of the PU/graphene composites in high-performance synthetic leather are summarized in this review. • Functionalization of polyurethane and graphene nano-derivatives including covalent and noncovalent modifications of the composites are covered. • We put forward some novel speculations for the composites and their synthetic leather manufacture in advanced areas. In recent years, polyurethane/graphene composites (PUGs) have attracted considerable attention attribute to their wide applications ranging from industrial manufacturing to bioengineering. The addition of graphene-based derivatives to the PU matrix can improve the mechanical, thermal, and electromagnetic properties, etc., to meet the specific demands of quality, functionality, and novelty of polymer composites. There are different modification methods of graphene and structural designs of polyurethane matrix for the applications of PUGs in various areas. Among the major applications, PUGs possess remarkable features in the dipping and coating process of synthetic leather. However, limited comprehensive summaries of functional PUGs have been published in broad fields and synthetic leather. The review aims to provide an overview of the cutting-edge developments of PUGs in the properties of thermal conduction and flame-retardance, antimicrobial, ultraviolet resistance, electromagnetic interference shielding, and oil–water separation respectively, which path a way for researchers to apply these uniquely functional composites for high-performance and advanced applications. And the applications of the PUGs in high-physical synthetic leather and the current challenges and prospects of synthetic leather in advanced fields are briefly presented. [ABSTRACT FROM AUTHOR]

Ti-6Al-4V is widely used in various fields of modern industry, but it is difficult to obtain an ultra-smooth surface of Ti-6Al-4V due to its poor machinability. In this article, ultraviolet-induced (UV-induced) nanoparticle colloid jet machining was utilized to carry out ultra-precision polishing of Ti-6Al-4V to improve the surface quality. The results of infrared differential spectroscopy before and after polishing show that new chemical bonds such as Ti-O-Ti (Al-O-Ti and V-O-Ti) appear on the Ti-6Al-4V workpiece surface, which indicates that the material of Ti-6Al-4V workpiece is removed through the chemical interaction between TiO2 nanoparticles and workpiece surface in the process of UV-induced nanoparticle colloid jet machining. The comparison of metallographic structure of Ti-6Al-4V before and after polishing shows that the chemical activity and material removal rate of the primary α phase in Ti-6Al-4V is higher than that of the remnant β phase in UV-induced nanoparticle colloid jet machining, which lead to the well-distributed nano-scale surface peaks and valleys at regular intervals on the polished Ti-6Al-4V workpiece surface. After polishing, the longitudinal residual stress on the surface of Ti-6Al-4V workpiece decreases from 75 MPa to 67 MPa and the transverse stress decreases from 13 MPa to 3 MPa. The surface roughness of Ti-6Al-4V workpiece is reduced from Sa 76.7 nm to Sa 2.87 nm by UV-induced nanoparticle colloid jet machining. [ABSTRACT FROM AUTHOR]

In this paper, ultraviolet (UV)-induced nanoparticle colloid jet machining is proposed to achieve ultrasmooth surface polishing by using the interaction between nanoparticles and the workpiece surface under the action of the ultraviolet field and the hydrodynamic pressure field. In the process of UV-induced nanoparticle colloid jet machining, the effects of photocatalysis on the interaction between nanoparticles and the workpiece surface need to be further studied in order to better understand the polishing process. This paper presents the interaction between TiO2 nanoparticles and a Si workpiece surface with and without ultraviolet irradiation. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were applied to investigate the differences in the interaction of TiO2 nanoparticles with Si workpieces. The SEM and XPS results indicate that the photocatalysis of UV light can promote the interaction between TiO2 nanoparticles and a Si surface by creating more interfacial reaction active centers between the TiO2 nanoparticles and the Si workpiece. The FT-IR and XPS spectra show that TiO2 nanoparticles are chemically bonded to the Si workpiece by oxygen-bridging atoms in Ti-O-Si bonds. Due to the effects of photocatalysis, UV-induced nanoparticle colloid jet machining has a higher polishing efficiency than nanoparticle colloid jet machining with the same polishing parameters. [ABSTRACT FROM AUTHOR]

Carbon-based (e.g. carbon fibers or carbon nanotube (CNT)) polymer composite materials, due to the high specific strength, and good chemical stability features, is a promising structural material for energy-efficient applications in aerospace and civil infrastructures. However, the difficulty of viscosity-related infusing and curing of polymer limits composite mechanical performance and manufacturing efficiency. Here we overcome these difficulties and report an electrothermal-triggered flooded thermoset curing to enable rapid and energy-efficient manufacturing of carbon/polymer composite. The underlying concept is based on the two-step localized in- situ infusion and curing in flooded polymer by Joule heating of carbon-based materials to facilitate the flow of polymer into the microstructure in low current, followed by curing of polymer resin in high current. The viscosity adjustment and defoaming process in the infusing process and the curing properties (degree of cure and strength) of the composites were used to prove the effectiveness of this curing strategy in composite fabrication. This electrothermal-triggered curing approach provides a rapid, energy-efficient, scalable, and volumetric composite manufacturing technique. Image 1 • An energy-efficient and scalable electrothermal-triggered thermoset curing approach. • The curing approach exhibits the ability to control the viscosity of the polymer. • Electrothermal preforms can facilitate the flow of polymer into the microstructure. • The preparation process of carbon fibers and CNTs composites was demonstrated. [ABSTRACT FROM AUTHOR]