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With an inherent lowest density and distinct solubility with enhanced mechanical behavior reason, the magnesium alloy composite is extensively used in the auto and aero sectors. The processing of magnesium alloy found micro‐cracks and voids between the oxidation spot, which fails properties. Through the sulfur hexafluoride (SF6) atmosphere, the AZ91D alloy hybrid nanocomposites are synthesized with 10 wt% alumina (Al2O3) and 0, 3, 6, and 9 wt% of silicon carbide (SiC) nanoparticles via a liquid state process with 400 rpm stir speed followed by vacuum die casting. The effect of SiC actions on physical behavior, microstructural formation, and mechanical properties of AZ91D/10 wt%Al2O3, AZ91D/10 wt%Al2O3/3 wt% SiC, AZ91D/10 wt% Al2O3/6 wt% SiC, and AZ91D/10 wt% Al2O3/9 wt% SiC composites are studied and its results compared with cast AZ91D alloy. Due to the actions of SiC in AZ91D/10 wt%Al2O3, the composite density conforms to the rule of mixture, and the void and micro‐cracks are limited (less than 1%) by the impact of the casting process, as evidenced in the microstructural illustration. An effect of 10 wt% Al2O3 and 9 wt% SiC contents in AZ91D facilitates maximum tensile strength of 181 MPa, improved elongation percentage of 2.2%, optimum hardness of 85HV, and superior impact toughness of 21.8 J/mm2, which is higher than the all other compositions. [ABSTRACT FROM AUTHOR]

The scope of the work is to develop in-organic–organic hybrid epoxy nanocomposites using a combination of DGEBA (CY 230) epoxy resin and areca fibre (Af) mixture in the ratio of 70:30, respectively. The mixture was reinforced with varying weight percentages (1 and 2 wt%) of surface-modified nanozinc oxide (M-nZnO) and cured with triethylene-tetra-amine (HY951) at room temperature. 3-aminopropyltriethoxysilane was used as a coupling agent to introduce amine groups on the surface of ZnO and its structure was confirmed by FT-IR. The thermal stability and mechanical properties of in-organic–organic hybrid epoxy nanocomposites having different weight percentages of M-nZnO are investigated by thermogravimetric analysis. Their surface morphology of in-organic–organic hybrid epoxy nanocomposites was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The introduction of M-nZnO improved the mechanical and thermal properties of the in-organic–organic hybrid epoxy nanocomposites. The mechanical characteristics and thermal stability analyses yielded the best results with a 2 wt% addition of M-nZnO nanoparticles. The study's findings clearly suggest that 2 wt% M-nZnO with Af/DGEBA epoxy resin can be used in a wide range of high-performance applications. Interestingly, the Af/DGEBA/M-nZnO epoxy nanocomposites displayed an excellent antibacterial action against high concentrations of Gram-negative bacteria like Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

The present study investigates the reciprocating wear behaviour of as-cast AZ91/Al2O3 nanocomposites. The amount of Al2O3 nanoparticles (particle size: < 50 nm) varied at 1.5 and 2 wt.%, and its effect on the wear behaviour of nanocomposites was examined using analysis of variance (ANOVA). The influence of wear parameters such as load, sliding speed, and time was also investigated. The reciprocating wear of nanocomposites was investigated on various counter discs, including as-cast, homogenized, non-homogenized, and SiC paper. All tests were performed at room temperature with a constant sliding distance of 20 mm. According to the findings, introducing nanoparticles enhanced wear resistance, and the main effect plots revealed a linear relationship between wear rate and time. According to the ANOVA, disc type, time, and composition are the most influential parameters on wear rate. Wear mechanisms and features of debris of worn specimens were investigated using SEM equipped with EDS analysis. Worn-out specimens under homogenized and non-homogenized counter disc conditions were extensively oxidized and found to be adhesive. Deep grooves, ploughs, and oxidized detritus were detrimental to specimens worn beneath an abrasive counter disc. [ABSTRACT FROM AUTHOR]

This study presents the preparation and comprehensive characterization of nanoparticles and a nanocomposite synthesized through the mediation of green tea extract. Zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles, as well as a TiO2-ZnO nanocomposite, were synthesized using green tea extract as a reducing and stabilizing agent. Characterization techniques including Scanning Electron Microscopy (SEM), Elemental Dispersive X Ray analysis (EDX), Fourier Infra-Red Spectroscopy (FT-IR) were employed to confirm the shape, elemental and chemical composition of the synthesized materials. The synthesized ZnO nanoparticles exhibited uniform spherical morphology, while the TiO2 nanoparticles displayed a fine, rounded rhombic shape. The TiO2-ZnO nanocomposite exhibited a combination of rhomboid and spherical particles, demonstrating its complex and heterogeneous structure. The study highlights the potential of green tea-mediated synthesis for producing nanoparticles and nanocomposites with diverse morphological features, offering opportunities for various applications in nanotechnology and materials science. [ABSTRACT FROM AUTHOR]

This study examines the piezoresistive behavior of MWCNT/polymer composites fabricated by the digital light processing (DLP) technique. A photocurable nanocomposite resin feedstock possessing low viscosity with excellent printability and high conductivity was developed for DLP 3D printing of bulk and cellular geometries. By optimizing the resin composition and synthesis route, electrical percolation was achieved at an ultra-low MWCNT loading of 0.01 phr (parts per hundred resin), providing a conductivity of 3.5 × 10−5 S m−1, which is significantly higher than the values reported in the extant works for similar nanocomposites. Reducing the MWCNT content also enhanced the piezoresistivity of the nanocomposite due to longer inter-MWCNT distances in the percolating conductive network. Under quasi-static tensile loading, the nanocomposite with 0.01 phr MWCNT loading showed gauge factors of 2.40 and 4.78, corresponding to the elastic and inelastic regime, respectively. Quasi-static cyclic tensile tests with constant strain amplitudes (within elastic regime) revealed that the response of the nanocomposite was affected by viscoelastic deformation, which caused significant changes in the material's strain sensing performance between consecutive load cycles. Finally, the developed resin was used to realize a self-sensing gyroid lattice structure, and its strain and damage sensing capabilities were demonstrated. [ABSTRACT FROM AUTHOR]

This research focused to synthesize the material by the tungsten inert gas (TIG) welding process with support of appropriate flux coating material. Therefore the required amount of flux coating material was utilized to enhance the mechanical properties of the specified localized welded regions. Hence, this study concentrated to select the nano-SiO2 flux particles that were employed for TIG process. This activated TIG welding composes the flux-coated welding on the base metal of AA5083-H111, as this material was highly reactive with SiO2 by the presence of magnesium precipitates and well synthesized after the welding. The post- and preheat treatment process was achieved before and after welding. The selection of activated TIG process parameters composed of strengthened weld specimens along with constant parameters like electrode tip angle and flow rate, respectively. Initially, the process parameters were designed by the statistical analysis of Box Behnken method with support of regression formulation to determine the optimal solution. The maximum tensile strength was attained at the welding process parameters of welding speed (100 mm/min), voltage (13 V), and current (125 amps). The higher hardness was achieved at the process parameters of welding speed (80 mm/min), voltage (12 V), and current (125 amps), respectively. Finally, the neural network approach was utilized to verify the predicted responses of tensile and microhardness properties. The interaction plots, mean plots, and 3D scatter plots were influenced to enhance the process parameters. In this research, mechanical properties were enhanced by the flux-coated SiO2 and the analytical method also advances the optimal parameters. [ABSTRACT FROM AUTHOR]

Herein, we report an enhanced sunlight-driven photocatalytic, supercapacitor and antibacterial applications based on graphene oxide (GO) and magnetite -graphene oxide (Fe 3 O 4 -GO) nanocomposites. The materials were synthesized by the facile chemical precipitation method and examined in detail by various techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–Visible (UV–Vis.) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and vibrating sample magnetometer (VSM). The effective production of GO and Fe 3 O 4 -GO nanocomposite was validated by XRD, while UV–Vis. measurements demonstrated a smaller bandgap for the nanocomposites. The uniform distribution of Fe 3 O 4 nanoparticles over GO nanosheets were observed through FESEM and TEM studies. The prepared materials were further utilized as sun-light driven photocatalyst for the degradation of methylene blue (MB) dye, working electrode for the supercapacitor application and efficient biomaterial to examine the antibacterial characteristics against Gram-positive (S. aureus) and Gram-negative (E. Coli) bacterial strains. As an efficient photocatalyst, the Fe 3 O 4 -GO nanocomposites exhibited a rapid degradation (91% in 30 min) for methylene blue dye under direct sunlight irradiation. The synthesized nanocomposite exhibited a maximum specific capacitance of 775 Fg-1 at a current density of 1 Ag-1 and exceptional chemical stability as an electrode material. Antibacterial activities of the synthesized materials were also exhibited against Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial strains. [ABSTRACT FROM AUTHOR]

Using the Taguchi Grey response surface approach, this study investigates the effect of novel ultrasonic-aided stir casting conditions on the production of AA6061/zirconia nanocomposites. A Taguchi L16 orthogonal array was utilized to conduct the researches, which included ultrasonic power (1.75-2.5 kW), time (5-20 min), temperature (750-900°C), which can cause premature solidification, stir pressure (100-250 MPa), and reinforcement weight percentage (wt% of reinforcement). Ultrasonic-aided stir casting technique has five adjustable parameters (2-5). The ultimate tensile strength, elongation percentage, hardness, and size of the grain material were some of the metrics used to evaluate the process performance. It was decided to employ the response surface approach to model and optimize the numerous replies into one grey relational analysis. AA6061/zirconia nanocomposites were studied using statistical methods such as 3D surface plots and variance analysis. 2.2537 kW, 16.28 min ultrasonic duration, weight % of reinforcement of 1.9, stirring temperature of 700.73°C, and stirring pressure of 142.63 MPa were found to be the best parameter values. [ABSTRACT FROM AUTHOR]

To generate hybrid high functionality epoxy nanocomposites, different weight percentages of amine-functionalized mullite fiber (F-MF) were mixed with tetraglycidyl (TGBAPB) epoxy resin. 3-Aminopropyltriethoxysilane (APTES) was used as a coupling agent to create an amine-functionalized mullite fiber F-MF. The TGBAPB epoxy resin was reinforced with various weight percentages (1, 1.5, and 2 wt%), of F-MF nanocomposite combinations and cured with 4,4′-diamino diphenylmethane (DDM). The molecular structure of F-MF was determined using Fourier transform infrared (FT-IR). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) investigated the morphology of hybrid epoxy nanocomposites. Furthermore, we identified a covalent link between the F-MF epoxy and TGBAPB epoxy matrix, which resulted in a considerable improvement in thermal, thermo-mechanical, mechanical, dielectric, and water absorption behavior in TGBAPB hybrid epoxy nanocomposites. Hence, we recommend the possible use of hybrid epoxy nanocomposites for advanced engineering applications that require both toughness and stiffness, which are essential for automotive, electronics and advanced aerospace applications for improved performance and longevity than the materials that are currently in use. [ABSTRACT FROM AUTHOR]

The (F-SBA-15) dispersed aliphatic chain containing polybenzoxazine nanocomposite coating materials having better corrosion resistance property has been developed. The new aliphatic chain containing polybenzoxazines is synthesized from n-octylamine, bisphenol-A and paraformaldehyde involving mannich condensation reaction. The structure of polymer and monomer was examined with the help of proton magnetic resonance1NMR spectroscopy and Fourier transform IR spectroscopy. The polybenzoxazine composites were prepared n-octylamine, bisphenol-A and paraformaldehyde and using varying percentages (1, 5, 10 wt%) of GPTMS functionalized mesoporous silica (F-SBA-15) through in situ polymerization process. The polybenzoxazine nanocomposites were characterized using X-ray powder diffraction and scanning electron microscopy. In addition Surface treated (F-SBA-15) dispersed polybenzoxazine nanocomposites has been prepared and studied for their N2 adsorption/desorption, water contact angle, dielectric behavior and anticorrosive properties. The polymer nanocomposites subjected to the highest water contact angle noted at 115° was attained for 10 wt% (F-SBA-15). The value of dielectric constant for neat, 1, 5, 10 wt% (F-SBA-15) incorporated polymer nanocomposites was noted as 4.7, 3.8, 2.9, and 2.1, respectively. The corrosion resistant capacity of BZ/(F-SBA-15), on mild steel specimens, was noticeably higher than that of conventional polybenzoxazine due to the hydrophobic aliphatic chain segments and porous structure of (F-SBA-15). [ABSTRACT FROM AUTHOR]

The sturdy demands in orthopaedics are not yet fulfilled, in both bone replacement and joint substitution and also in other repairs of bone defects. Metals are used for bone repair and replacement for a long period of time instead of biomaterial. Most of the countries are still now practising bone replacement with metals like titanium and stainless steel only due to the lag of technology advancement. A lot of research and development paves the way to composite biomaterial, as it is evolving in the domain of treatment of orthopaedics. There was massive research undergoing in the biomaterial field recently, and various methods of fabrication have been tested and implemented. Nanocomposites provide a higher surface-to-volume ratio, surface chemistry and nanoscale reinforcement, flexible production techniques, good corrosion and erosion resistance, and cheaper costs. The nanocomposite biomaterials were intended for biomedical purposes. Because of the intricacy of biological structures (tissue or organ) and additive manufacturing techniques for tissue engineering, scaffolding has wide scope for instant remedies in bone implant. The design restrictions and physical attributes of fast prototyping structures are then evaluated in terms of input factors like design elements, material choices, and additive manufacturing processing parameters. As a result of this survey, the needs and application importance of additively manufactured implants for the regeneration of various biomaterial types as well as the attempts undertaken to mitigate their medical impairment are suggested. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding has potential importance due to rapid growth in electronic technology. In recent days, carbon nanomaterials and conducting polymer nanocomposites grab much attention for EMI shielding applications. Nanocomposites of polyaniline (PANI) and single-walled carbon nanotubes (SWCNTs) were synthesized by ultrasonically induced in situ polymerization technique. The content of the SWCNT filler is varied as 1, 2, 3, 4 and 5 wt%. Fourier transform infrared spectroscopy was used to quantitatively analyse the functional groups of nanocomposites. Raman spectra revealed good compatibility between PANI and SWCNTs phases. The surface morphology of nanocomposites was analysed by field emission scanning electron microscope. The microwave absorption ability of the nanocomposites was estimated by determining shielding effectiveness in the range of 8.2–12.4 GHz (X-band). The total shielding effectiveness was found to increase with increase of SWCNT phase in PANI matrix and the maximum value of − 32.80 dB at 11 GHz with 99.999% absorption was obtained for 3 wt% of SWCNT sample. Dynamic mechanical properties were studied as a function of temperature. The complex permittivity and electrical conductivity of PANI-SWCNT nanocomposites are also studied. The complex permittivity (ɛ′ and ɛ″) and AC conductivity were found to be higher in PANI-SWCNTs nanocomposites as compared to the PANI. The increasing behaviour has been attributed to the good interaction between SWCNTs and PANI molecular chains. The present results reveal that the current sample materials are suitable for shielding the devices from EMI in X-band frequency region. [ABSTRACT FROM AUTHOR]

Within the scope of the study, the thermal conductivity (TC) and thermal diffusivity (TD) of hexagonal boron nitride (h-BN) and reduced graphene (r-GO)-based epoxy nanocomposites were investigated and compared. In addition, the dielectric properties and electrical conductivity of the two were also investigated. The heat transport phenomenon of h-BN/epoxy and r-GO/epoxy nanocomposites were investigated using the transient plane source (HOT DISK) technique at room temperature. The h-BN/epoxy nanocomposites exhibited a higher thermal transport than the r-GO/epoxy nanocomposites. A high TC of ~ 2.6 W/mK and a high TD of ~ 9 mm2/s were observed at a h-BN loading of 2 vol% in the nanocomposite. The TC and TD values were ~ 33% and ~ 119% higher than r-GO/epoxy nanocomposite. The relative dielectric permittivity (ε r) and loss (δ) was observed to be higher for r-GO/epoxy nanocomposite when compared to h-BN/epoxy nanocomposites. High relative dielectric permittivity of ~ 7.5 and loss of ~ 0.07 was obtained at a r-GO loading of ~ 2.2 vol% in the nanocomposite. Further, both nanocomposites retained a high electrical resistance. The study indicates h-BN/epoxy nanocomposite to hold significant potential for heat management in electronic applications. [ABSTRACT FROM AUTHOR]

In this study, an attempt was made on the AA2024 alloy based hybrid nanocomposites reinforced with different weight percentage of SiC and B4C particles to investigate their physical and machinability characteristics including surface morphology. The Material Removal Rate (MRR), Surface Roughness (SR) of the nanocomposites machined by various machining processes namely Abrasive Water Jet (AWJ) machining, Wire Electrical Discharge (WED) machining and Computer Numerical Controlled (CNC) turning processes were studied comparatively. The machined surface formed by the each machining process is examined and its surface quality was discussed for each hybrid nanocomposite. Results show that the hardness is increased to 101.6 BHN from 179.4 BHN, when 2 wt.% of B4C and SiC particles is added to AA2024 matrix. Observed from the results that the addition of 2 wt.% of B4C and SiC particles produces the highest porosity of 3.36% for nanocomposite samples. The experimental results revealed that the addition of particulates in to the matrix reduces the MRR and increases SR. MRR results showed that hybrid nanocomposites machined by AWJ technique has minimum MRR of 0.0221 mm3/min. The surface roughness of the nanocomposites machined with AWJ process was 3.2 µm and increased to 6.81 µm for the AA2024-B4C-SiC hybrid nanocomposites machined with CNC process. [ABSTRACT FROM AUTHOR]

We report the first of its kind synthesis of CeO2/La2O3 nanocomposites that are with integrated mesoporous TiO2 monoliths, with well-defined structural and surface properties, to act as visible-light responsive photocatalysts. The structural features of the photocatalyst materials are defined using HR-TEM, p-XRD, FE-SEM, SAED, EDAX, XPS, PLS, TGA, IR, UV–Vis–DRS and BET/BJH analyses. The stoichiometric infusion of CeO2/La2O3 nanocomposites with the monolithic TiO2 network reduces the bandgap energy from 3.26 to 2.52 eV, thus promoting excellent visible-light photocatalysis. To evaluate the photocatalytic efficiency of the proposed photoactive materials, two antimicrobial drugs namely, moxifloxacin and ciprofloxacin are selected as target pollutants. It is observed that the uniform and continuous porous monolithic network ensures easy transport of pollutant molecules to the photoactive sites, thereby felicitating their faster dissipation. The influence of various physico-chemical parameters has been studied by photolysis and photocatalysis procedures, and the extent of drug degradation is quantitatively analysed by using a robust HPLC-DAD method. The photocatalysis results reveal that the monolithic photocatalyst can serve efficiently for environmental remediation applications, with excellent reusability character. [ABSTRACT FROM AUTHOR]

In the present study, a lightweight and flexible polyvinylidene fluoride (PVDF)/zinc oxide (ZnO) nanocomposite was prepared using a low‐temperature phase‐inversion process. The synergetic effect of low‐temperature, phase‐inversion, and the integration of ZnO nanoparticles primes on enhancing the electroactive polar β‐phase in the nanocomposite. The transformation of the electroactive phase and its quantification were carried out using Fourier‐transform infrared spectroscopy and wide‐angle X‐ray diffraction. The PVDF/ZnO piezoelectric polymer nanocomposite was utilized for energy harvesting application that showed a better electromechanical response of ca. 69 V (peak to peak) at ~1.6 N, 250 μW/cm2 surface power density and 0.25 mA/cm2 surface current density. The fabricated piezoelectric polymer nanocomposite is a possible candidate for superior energy scavenging applications for capturing human kinematics. [ABSTRACT FROM AUTHOR]

There is a significant interest in the analysis of biphasic temperature pattern for natural family planning (NFP). In this paper, we report an IoT enabled Basal Body Temperature (BBT) monitoring system—designed and developed using a NiMn2O4 nanocomposite powder based thermistor. BBT is the lowest body temperature attained at rest and normally ranges from 308.70 to 310.65 K. The pelletized active material NiMn2O4 was placed in a thermally conductive Teflon tube with Aluminum (Al) metal contacts on either side as electrical contacts to the active material. Resistance of the Al/NiMn2O4/Al composite structure is inversely proportional to temperature changes. A resistance change of 953000 ± 500 to 591000 ± 450 Ω was observed for a change of basal body temperature from 304.65 to 313.15 K with a correlation coefficient (R²) of 0.9628. Real time monitoring of BBT was facilitated by Node MCU and Thing Speak IoT platform for predicting the ovulation pattern in women. [ABSTRACT FROM AUTHOR]

In the present study, we report a simple fabrication method for poly(vinylidene fluoride) PVDF/MWCNT flexible nanocomposite films with a boosted electroactive phase that enhanced the dielectric and piezoelectric properties. The PVDF films were prepared by using the phase inversion method for which water was a non-solvent. Initially, neat PVDF films were prepared in a temperature-controlled non-solvent with varying temperatures from 5 °C to 40 °C respectively. Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and differential scanning calorimetry (DSC) were carried out to confirm the electroactive phase and percentage crystallinity of the film. The electroactive β-phase of PVDF exhibited an enhancement with a decrease in temperature. At 5 °C, PVDF showed a β-fraction of ca. ∼54.4%, with a percentage crystallinity of ca. ∼57.4%. With the systematic addition of Multi-walled carbon nanotubes (MWCNTs), it was observed that the β-fraction and the crystallinity of PVDF were enhanced. A dramatic improvement in the electroactive phase was observed upon the addition of 0.25 wt% MWCNTs, with a β-phase content of PVDF of ca. ∼93.8% and crystallinity of ca. ∼61.8%. The augmented polar phase changed the dielectric and piezoelectric properties of the PVDF nanocomposites. [ABSTRACT FROM AUTHOR]

Abstract In the present study, a nanocomposite cathode comprising Fe rich La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) based pervoskite semiconductor oxide and Sm-Gd co-doped ceria rich Ce 0.8 Sm 0.1 Gd 0.1 O 1.90 (CSGO) in the ratio of 1:1 has been successfully synthesized by a simple glycine nitrate auto combustion method. The structural properties of the two phase nanocomposite were evaluated by X-ray diffraction and Raman spectroscopy. A detailed electrical properties of co-doped LSCF-CSGO nanocomposites have been studied with a comparison of LSCF added with 10 mol% and 20 mol% Gd singly doped ceria (LSCF-GDC10 and LSCF-GDC20) nanocomposites as a function of temperature in the range of 673–1073 K at air atmosphere by AC impedance spectroscopy. The total electrical conductivity of the co-doped LSCF-CSGO nanocomposites has been found to be 0.043 S cm−1 at 973 K which is higher than that of the LSCF composite containing singly doped compositions. The Sm co-doping in GDC phase has effectively helped to reduce the undesired electronic conduction produced in the doped ceria as the electron concentration of LSCF-CSGO was found to be − 2.62 × 1015 cm−3 which was lower than the electron concentration of LSCF containing singly doped nanocomposite (LSCF-GDC20, − 2 ×1016 cm−3) estimated by Hall-Effect measurement. The activation energy of LSCF-CSGO nanocomposite has been found to be 0.05 eV for the oxygen reduction reaction by temperature dependent Arrhenius equation. The improved electrical properties in terms of high ionic conductivity and low activation energy have been achieved through the incorporation of Sm into GDC10 electrolyte phase in LSCF nanocomposite. The combustion synthesis method has also effectively helped to produce microstructure containing large grain size (~ 6 µm) which is beneficial for enlarging triple phase boundary (TPB) area of cathodes utilized in solid oxide fuel cells (SOFC) operated at reduced/intermediate temperature (673–973 K). [ABSTRACT FROM AUTHOR]

Abstract Herein, we report strain- and damage-sensing performance of biocompatible smart CNT/UHMWPE nanocomposites for the first time. CNT/UHMWPE nanocomposites are fabricated by solution mixing followed by compression molding. The surface morphology, microstructural properties, thermal decomposition and stability, glass transition temperature and thermal conductivity of the nanocomposites are characterized. The degree of crystallinity of CNT/UHMWPE nanocomposites is found to have a maximum value of 52% at 0.1 wt% CNT loading. The degree of crystallinity influences the mechanical properties of the CNT/UHMWPE nanocomposites. The electrical percolation threshold is achieved at 0.05 wt% of CNT and it follows a two dimensional conductive network according to percolation theory. The piezoresistive response of CNT/UHMWPE nanocomposites is demonstrated with a gauge factor of ~2.0 in linear elastic regime and that in the range of 3.8–96.0 in inelastic regimes for 0.05 wt% of CNT loading. A simple theoretical model is also developed to predict the resistivity evolution in both elastic and inelastic regimes. High sensitivity of CNT/UHMWPE nanocomposites coupled with linear piezoresistive response up to 100% strain demonstrates their potential for application in artificial implants as a self-sensing material. Graphical abstract Unlabelled Image Highlights • Self-sensing performance of CNT/UHMWPE nanocomposites is reported for the first time. • The electrical percolation threshold is achieved at 0.05 wt% of CNT loading. • CNT/UHMWPE nanocomposites exhibits a gauge factor of ~2.0 in linear elastic regime. • A simple theoretical model is developed to predict the resistivity evolution with stretch. • Strong piezoresistivity up to 100% strain demonstrates their candidacy for knee implants. [ABSTRACT FROM AUTHOR]

In this study, the unique characteristics of chitosan, reduced graphene oxide (rGO) and cerium oxide (CeO 2) based hybrid bionano-composites make a carrier for various drug delivery and antimicrobial applications. The recent literatures shown that addition of biopolymers to rGO and CeO 2 based nanocomposites exhibit excellent performance in design and development of biosensors, wound dressings, electrodes, microfluidic chips, drug delivery systems and energy storage applications. Chitosan (CS), reduced graphene oxide (rGO) mixed with cerium oxide (CeO 2) to form CS-rGO and CS-rGO-CeO 2 hybrid bionano-composites using precipitation method. The physiochemical characterization of casted nanocomposite sheet was done using FTIR, XRD, UV–Vis spectrum, SEM and TGA. The XRD results of CS-rGO-CeO 2 revealed that the nanoparticle was found to be crystalline structure. FTIR revealed that nitrogen functionalities of CS interacted with rGO-CeO 2 to form hybrid nanocomposites. The thermal gravimetric analysis (TGA) showed that the CS-rGO-CeO 2 has better thermal stability up to 550 °C. The SEM confirms the surface morphology of CS-rGO-CeO 2 has large surface area with smooth surface. Moreover, the antibacterial properties of nanocomposites exhibit excellent zone of inhibition against Staphylococcus aureus and Escherichia coli. The NIH3T3 cell line evaluations showed superior cell adhesion on hybrid nanocomposites. Hence bionano-composite based on CS, rGO and CeO 2 are potential biomaterials for drug delivery and antibacterial applications. [Display omitted] • CS-rGO-CeO 2 bionano-composite was prepared by simple, facile one-pot co-precipitation method. • CS-rGO-CeO 2 bionano-composite has better biocompatibility and superior antimicrobial efficacy against tested pathogens. • CS-rGO-CeO 2 bionano-composite exerted strong drug release and significant cytotoxicity against A549 cell lines. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE)-based conductive nanocomposites with reduced percolation and tunable piezoresistive behavior were prepared via solution mixing followed by compression molding using carbon nanotubes (CNT) and graphene nanoplatelets (GNP). The effect of varying wt% of GNP with fixed CNT content (0.1 wt%) on the mechanical, electrical, thermal and piezoresistive properties of UHMWPE nanocomposites was evaluated. The combination of CNT and GNP enhanced the dispersion in UHMWPE matrix and lowered the probability of CNT aggregation as GNP acted as a spacer to separate the entanglement of CNT with each other. This has allowed the formation of an effective conductive path between GNP and CNT in UHMWPE matrix. The thermal conductivity, degree of crystallinity and degradation temperature of the nanocomposites increased with increasing GNP content. The elastic modulus and yield strength of the nanocomposites were improved by 37% and 33%, respectively, for 0.1/0.3 wt% of CNT/GNP compared to neat UHMWPE. The electrical conductivity was measured using four-probe method, and the lowest electrical percolation threshold was achieved at 0.1/0.1 wt% of CNT/GNP forming a nearly two-dimensional conductive network (critical value, t = 1.20). Such improvements in mechanical and electrical properties are attributed to the synergistic effect of the two-dimensional GNP and one-dimensional CNT which limits aggregation of CNTs enabling a more efficient conductive network at low wt% of fillers. These hybrid nanocomposites exhibited strong piezoresistive response with sensitivity factor of 6.2, 15.93 and 557.44 in the linear elastic, inelastic I and inelastic II regimes, respectively, for 0.1/0.5 wt% of CNT/GNP. This study demonstrates the fabrication method and the self-sensing performance of CNT/GNP/UHMWPE nanocomposites with improved properties useful for orthopedic implants. [ABSTRACT FROM AUTHOR]

This study investigated the role of poly-ethylene glycol (PEG) in the microwave synthesis of ZnO (ZPMx) nanorods. The molecular weight of PEG was found to strongly influence the aspect ratio of the synthesized material. The as-prepared ZPMx nanorods were post-grafted onto the surface of GO sheets using 3-amino propyl trimethoxy silane (APTMS) as a cross-linking agent to obtain ZPMx-Si@GO hybrid nanocomposites. Microscopic observations showed that ZPMx nanorods with different aspect ratios were evenly distributed on the surface of the GO sheets. It also showed enhanced thermal and chemical properties. The dependence of the antibacterial behavior on the aspect ratio of the ZPMx nanorods and GO was also investigated. An antibacterial assay was carried out using both the Gram-positive bacteria Staphylococcus aureus ( S. aureus ) and Gram-negative bacteria Escherichia coli ( E. coli ), and Klebsiella pneumonia ( K. pneumonia ). The results showed that the ZPMx-Si@GO hybrid nanocomposite had an excellent antibacterial property toward the test bacteria compared to pure ZPMx and GO. The synergistic effect of ZPMx and GO resulted in a superior antibacterial activity in ZPMx-Si@GO. Interestingly, the hybrid nanocomposite with a higher ZPMx aspect ratio (ZPM6000-Si@GO) showed excellent inhibition zones with diameters of ∼3.7, 3.1, and 2.4 cm corresponding to S. aureus , E. coli , and K. pneumonia , respectively. An optical density measurement, as well as the morphological changes in the bacteria, again confirmed the excellent bacterial growth inhibition of ZPM6000-Si@GO. The studies indicated that the ZPMx-Si@GO hybrid nanocomposite is a promising candidate for use in real waste-water disinfection. [ABSTRACT FROM AUTHOR]

In this study, mineral-substituted hydroxyapatite (M-HA (5, 10, and 15 wt%)) reinforced poly(raffinose-citric acid)–polyethylene glycol–poly(raffinose-citric acid) (PRC–PEG–PRC) was synthesized employing a microwave irradiation technique. The ability of the fabricated nanocomposite for bone development was studied in vitro using human osteosarcoma HOS MG63 cells and in vivo after subcutaneous implantation into Wistar rats. This porous M-HA/PRC–PEG–PRC nanocomposite encouraged the adhesion, growth, and multiplication of HOS cells, as displayed by their uniform morphology and as determined by cell adhesion and the live/dead cell assay. Upon osteogenic differentiation, superior ALP activity and bone-related gene expression were observed for the HOS cells on the M-HA/PRC–PEG–PRC nanocomposite compared with the cells on pure PRC–PEG–PRC scaffolds. In in vivo implantation experiments, ossification and development of trabeculae were detected on the M-HA (15 wt%)/PRC–PEG–PRC nanocomposite in contrast to pure PRC–PEG–PRC. In addition, the porous M-HA (15 wt%)/PRC–PEG–PRC nanocomposite demonstrated the capacity for ectopic bone arrangement. Moreover, decreased numbers of bacterial colonies of Staphylococcus aureus and Escherichia coli were observed in the presence of the M-HA/PRC–PEG–PRC scaffolds, indicating the reduced risk for implant failure after implantation. The good cell affinity of the M-HA/PRC–PEG–PRC porous materials indicated that they might be used as scaffolds for bone tissue engineering. [ABSTRACT FROM AUTHOR]

In the present work, tetraglycidyl 1,4′-bis (4-amine-phenoxy) benzene (TGBAPB) epoxy resin has been developed using 1,4′-bis (4-amine-phenoxy) benzene and epichlorohydrin. The amine-functionalized nanoalumina (F-nAl) was prepared using 3-aminopropyltriethoxysilane. TGBAPB epoxy resin was further reinforced with different weight percentages (1–5 wt%) of F-nAl and were cured with 4,4′-diaminodiphenylmethane. Thermal and thermomechanical behavior of TGBAPB epoxy matrix and nanocomposites were studied using thermogravimetric and differential scanning calorimetric analyses. The surface morphology of epoxy nanocomposites was examined using transmission electron microscopic, scanning electron microscopic, and atomic force microscopic studies respectively.Data obtained from mechanical and thermal studies/analysis indicate that these nanocomposites could be used as high-performance materials for varied advanced industrial and engineering applications. [ABSTRACT FROM AUTHOR]

The optical response time of a nematic liquid crystal (NLC) decreases due to incorporation of carbon nanotubes (CNTs) in the liquid-crystal host. Such reduction is believed to be due to an increase in the elastic constant of the nanotube-doped LC system. In this paper, we present the effect on optical response due to doping an NLC with octadecylamine functionalised single-walled carbon nanotubes (ODA-SWCNT) in a twisted alignment mode. The electro-optic switching amplitude of ODA-SWCNT nanocomposites of NLC decreases compared to pure NLC. A fast response time is observed with an increase in the concentration of ODA-SWCNT in NLC host. Additionally, optical response of pure NLC in a twisted nematic (TN) cell fabricated using mixtures of polyimide (PI) and ODA-SWCNT as an alignment layer is investigated. The optical response time decreased by ~75% in a TN cell fabricated with a mixture of PI and ODA-SWCNT compared to that of a TN cell prepared using a pure PI alignment layer. The presence of ODA-SWCNT in the alignment layer enhances the surface anchoring of the NLC molecules leading to an increase in the elastic constant and a decrease in the optical response time of NLC. [ABSTRACT FROM PUBLISHER]

We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70 S/cm at 1MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt.% graphite in PVDF. [ABSTRACT FROM AUTHOR]

Abstract: A stable aqueous suspension of a functional graphene/silver (FG/Ag) nanocomposite was prepared by an environmentally friendly hydrothermal method. The precursor, functional graphene oxide (FGO), was prepared by covalent functionalisation of graphene oxide (GO) with a hydrophilic organosilane, N-(trimethoxysilylpropyl) ethylenediaminetriacetic acid trisodium salt (TETA). The attachment of functional groups on the GO surface maintained the aqueous stability of the FG/Ag nanocomposite even after the hydrothermal reduction. Field emission scanning electron microscopy (FESEM) images illustrated a uniform distribution of Ag nanoparticles on the FG surface. The surface enhanced Raman spectroscopy (SERS) activity of the nanocomposite was investigated using p-aminothiophenol (p-ATP) and melamine which can be detected as low as 2×10−8 and 2×10−7 M, respectively. The impressive water stability and the high SERS sensitivity of the FG/Ag nanocomposite make it a suitable substrate for trace analysis of a variety of drugs, additives or organic contaminants in water. The nanocomposite also showed a positive inhibition effect against the growth of Escherichia coli bacteria, eliminating the possibility of bacterial contamination of the sensor, thus prolonging the shelf-life of the sensing device. [Copyright &y& Elsevier]

Abstract: Magnetically separable graphene-Fe2O3/ZnO (G-Fe2O3/ZnO) nanocomposites were prepared by a simple hydrothermal method, using graphene oxide (GO) and Zn(OH)2 as the precursors of graphene and ZnO, respectively and commercially available iron oxide (Fe2O3) as a magnetic material. The nanocomposite materials were characterised by Transmission Electron Microscopy (TEM), Field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD), Ultraviolet–visible spectroscopy (UV–vis) and Raman spectroscopy. Under natural sunlight, the nanocomposite exhibited excellent photocatalytic degradation of methylene blue (MB). Photoluminescence spectra proved that the high photocatalytic performance of the nanocomposite resulted from the prevention of electron–hole recombination by the effective transfer of electrons between the semiconductors and the graphene. The nanocomposite maintained its ability to degrade MB efficiently, even after 5 cycles of photocatalysis. [Copyright &y& Elsevier]

Abstract: Nanocomposites comprising a ferromagnet and an antiferromagnet have drawn attention recently because of their interesting physical properties and variety of technological applications. In the present work, structural, hyperfine and magnetic properties of Fe/Co3O4 nanocomposites prepared by a chemical route having 10–70 wt.% of Fe, have been investigated. XRD and TEM measurements confirmed polycrystalline nature of the samples having grain size in the nanometer regime. FTIR measurements show the presence of two bands of Co–O corresponding to Co2+ and Co3+. Mössbauer spectra recorded at room temperature confirm the presence of Fe in the blocked state. Presence of exchange bias at Fe–Co3O4 interfaces is confirmed by the magnetization measurements. Irreversibility in temperature dependent FC–ZFC measurements points to interface effect. Frequency dependent ac susceptibility measurements as well as memory effect observed in dc magnetization measurements indicate the superspin glass nature of the nanocomposites. [Copyright &y& Elsevier]

The nanoparticles of spinel ferrites having composition NiCaFeO were synthesized by an advanced sol-gel method and subsequently coated with intrinsically conducting polypyrrole (PPy) by chemical oxidative polymerization of the corresponding monomer (pyrrole) using ammonium peroxodisulphate as oxidant. The X-ray diffraction and TEM measurements were obtained to understand the crystalline structure, size and morphology of evolution of the samples. The dc electrical investigation revealed that at room temperature the surface conductivity increased from 2.8×10 S cm to 1.5×10 S cm on polymerization. Mössbauer investigations revealed that the polymerization causes migration of Fe ions from A to B site, resulting to the enhancement of the observed hyperfine field. In agreement with this, the dc magnetization measurements performed on VSM revealed an enhancement in saturation magnetization in the M- H curves on polymerization. The value of blocking temperature ( T) is found to have credibly increased from 110 K to 130 K, which confirms the increase in crystallite size after polymerization. [ABSTRACT FROM AUTHOR]

A study was made in the present investigation on the development and characterization of triphenyl phosphine oxide based phosphorus tetraglycidyl epoxy nanocomposites denoted as 'C' and to find out its suitability for use in high performance applications. The synthesized resin was characterized by Fourier transform infrared spectra (FT-IR) and H, C nuclear magnetic resonance (NMR) spectra. Nanoclay and POSS-amine nano-reinforcements denoted as N1 and N2 were incorporated into the synthesized epoxy resin. Curing was done with diaminodiphenylmethane (DDM) and bis(3-aminophenyl) phenylphosphine oxide (BAPPO) curing agents denoted as X and Y, respectively. Mechanical, thermal, flame retardant, water absorption behaviour and electrical properties of the epoxy nanocomposites were studied and the results are discussed. [ABSTRACT FROM AUTHOR]

Poly (ethylene- co-vinyl acetate) (EVA)/clay nanocomposites containing two different organoclays with different clay loadings were prepared. The transport of gases (oxygen and nitrogen) through the composite membranes was investigated and the results were compared. These studies revealed that the incorporation of nanoclays in the polymer increased the efficiency of the membranes toward barrier properties. It was also found that the barrier properties of the membranes decreased with clay loadings. This is mainly due to the aggregation of clay at higher loadings. The morphology of the nanocomposites was studied by scanning electron microscopy, transmission electron microscopy and X-ray scattering. Small angle X-ray scattering results showed significant intercalation of the polymer chains between the organo-modified silicate layers in all cases. Better dispersed silicate layer stacking and more homogeneous membranes were obtained for Cloisite® 25A based nanocomposites compared with Cloisite® 20A samples. Microscopic observations (SEM and TEM) were coherent with those results. The dispersion of clay platelets seemed to be maximized for 3 wt % of clay and agglomeration increased with higher clay loading. Wide angle X-ray scattering results showed no significant modifications in the crystalline structure of the EVA matrix because of the presence of the clays. The effect of free volume on the transport behavior was studied using positron annihilation spectroscopy. The permeability results have been correlated with various permeation models. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

This article reports the synthesis, charge transport studies, and microwave shielding properties of polyaniline-Ti-doped γ-FeO nanocomposite. The composite has been prepared by the in situ chemical oxidative polymerization using dodecylbenzenzesulfonic acid as a dopant. These resulting polymer composites have been found thermally stability up to 260 °C with magnetization value of ~10 emu/g. The temperature dependence of electrical conductivity reveals the applicability of Mott's 3D-VRH model. The composites has shown the shielding effectiveness of 35.64-45.20 dB (>99.99% attenuation) in 12.4-18 GHz (Ku-Band) frequency range. The enhancement of SE has been due to combination of dielectric and magnetic losses leading to decrease in skin depth increase in total (σ) conductivity and better matching of input impedance. [ABSTRACT FROM AUTHOR]

The low-temperature magnetic behavior of pure iron nanocrystallites dispersed in MgO matrix has been investigated by dc magnetization and ac susceptibility measurements. Irreversibilities in the magnetization data at low field are observed at low temperatures, indicating a passage from a high temperature ferromagnetic phase to a low-temperature disordered, frozen state. Quenching of these irreversibilities is seen when the external magnetic field is increased. The variation of the in-phase susceptibility with temperature showed marked frequency dependence whereas the out-of-phase susceptibility component passes through a maximum. The origin of this behavior is traced to the spin disorder at the grain boundaries, which exhibit a co-operative freezing below a certain temperature. [ABSTRACT FROM AUTHOR]

An approach to enhance the dispersion of multi-walled carbon nanotubes (MWCNT) within a polymer matrix is reported. MWCNT surface was modified with a second type of particle, which constitutes a third phase. MWCNT were modified with polycarbosilane-derived silicon carbide (SiC) particles. X-ray diffraction confirmed the formation of β-SiC particles. At a loading level of 1.5 wt%, a fine dispersion of MWCNT throughout the polyethersulfone (PES) was observed by scanning electron microscopy (SEM), but at a higher loading (2.5 wt%), agglomerates of carbon nanotubes were observed. At 2.5 wt% loading, the incorporation of SiC-modified MWCNT in PES showed a homogeneous dispersion of carbon nanotubes throughout the matrix as confirmed by SEM and transmission electron microscopy (TEM). TEM analysis also confirmed the synergistic interactions and improved dispersion of MWCNT within the polymer matrix. Incorporation of SiC-modified MWCNT (SiC-MWCNT) significantly improved the mechanical and thermal properties of PES composites compared to pure PES and a composite containing an equal amount of unmodified MWCNT. The increased quality and improved state of dispersion in the case of a SiC-MWCNT-filled composite can be correlated to an increase of electrical resistivity. [ABSTRACT FROM PUBLISHER]

Nanocomposites of mixed oxides of iron and neodymium in polymer matrix of aniline-formaldehyde are reported. The composites have been obtained by treating the aqueous solution of aniline, hydrochloric acid and formaldehyde with halide of iron and neodymium oxide. The infra-red spectra show broad peaks at ∼ 590 cm and at ∼ 610 cm due to the presence of oxides of both iron and neodymium. In heated samples, the absorption peaks due to metal oxides are better resolved. A broad and strong peak in XRD spectra at 2 θ value of 35.69920 corresponds to spinel γ-FeO. Fe Mössbauer spectrum for unheated sample gives Mössbauer parameters, i.e. isomer shift ( δ), quadrupole splitting (Δ E) and effective magnetic field (H). Transmission electron microscopy (TEM) micrographs reveal well dispersed particles at different magnifications. Vibrating sample magnetometry (VSM) studies indicate that the ferrite nanoparticles exhibit characteristics of ferromagnetism. [ABSTRACT FROM AUTHOR]

Abstract: The influence of low cost, commercially oxidized carbon nanofibers (ox-CNFs) on the morphological, thermal, mechanical and electrical properties of polycarbonate (PC) composites was examined. Using a simple solution mixing process leads to good dispersion and high packing density of CNFs in the resultant composites. The composite materials exhibit a dramatic improvement in the DC conductivity; for example, increasing from 2.36×10−14 S/m for PC to ca. 10−2 S/m for the composite at only 3.0 wt.% of CNFs, and exhibits a very fast static charge dissipation rate. Dynamic mechanical analysis showed a remarkable increase in storage modulus (282%) at 165°C, compared to pure PC. Thermogravimetric analysis showed that thermal stability of the composites increased by 54°C compared to the pure PC. To our knowledge, the measured electrical conductivity and thermal properties for PC/CNF are the highest values yet reported for PC/CNF composites at comparable loadings. The AC/DC conductivity is shown to play an important role to predict the state of dispersion. [ABSTRACT FROM AUTHOR]

• Synthesis of Mn 3 O 4 -rGO nanocomposite by simple solvothermal method. • Structural XRD exhibits a tetragonal structure with an average particle size ~26 nm. • Mn 3 O 4 -rGO shows the Bandgap of ~2.8 eV. • Mn 3 O 4 + rGO nanocomposites shows excellent efficiency towards methylene blue dye. Hausmannite manganese oxide/reduced graphene oxide (Mn 3 O 4 -rGO) nanocomposite (NC) was synthesized by solvothermal method. The NC was assessed for structural, morphological, and optical properties by XRD, SEM, FE-SEM, Raman, UV–visible and PL techniques. The XRD pattern exhibits a tetragonal structure of Mn 3 O 4 with an average grain size of ~25.81 nm. Crystalline plane (0 0 2) confirms the successful formation of Mn 3 O 4 -rGO NC. Surface morphological images show the crumbled-like structure of graphene sheets on which Mn 3 O 4 nanoparticles (NPs) are randomly distributed. The optical absorption and transmittance properties of NC were studied and the band-gap value was calculated. The photocatalytic activity studies on the degradation of methylene blue (MB) dye under sunlight demonstrated that Mn 3 O 4 -rGO NC have high degradation efficiency compared to the pristine materials Mn 3 O 4 and rGO. [ABSTRACT FROM AUTHOR]

Nanocomposite of Fe/CoO having 10 at. wt. % of α-Fe has been prepared by the high energy ball-milling method. The average particle size was estimated to be 15 nm from the results obtained by the rietveld refinement of x-ray diffraction pattern. The presence of exchange coupling at the interface of ferromagnetic and antiferromagnetic components was confirmed from the shift observed in field-cooled (FC) magnetic hysteresis loop. Irreversibility in temperature dependent zero field cooled (ZFC)-FC magnetization at different applied fields indicates the presence of spin-glass like (SGL) phase. Memory effect observed in the temperature dependent dc-magnetization at FC condition confirmed the existence of SGL state. It is argued that polydispersity and defects at the interfaces of nanoparticles are the possible causes of the observed SGL phase. [ABSTRACT FROM AUTHOR]

Bi-layer absorbers, which include porous and hierarchical materials, benefit from their slight weight, garnering increased interest in electromagnetic wave dissipation adaptability. However, developing a simple manufacturing process and utilizing such unique structures with particular compounds to achieve rational electromagnetic wave dissipation performance remains a challenge. In this case, a novel hierarchical flower-like Mo 2 C particle and scraps' firewood-shaped La 0.6 Sr 0.4 MnO 3 were chemically synthesized and employed as the single component in each layer of a manufactured double-layer absorber. The mechanical and electromagnetic wave dissipation capability of optimized bilayer absorber samples was excellent. The best absorption was found in bilayer samples with a total thickness of just 1.2 mm, –39 dB dissipation intensity, and 3 GHz bandwidth at 5.4 GHz frequency. This performance was obtained by manipulating the order and layer thickness of the components, as well as modifying their morphology and microstructure. [Display omitted] [ABSTRACT FROM AUTHOR]

The present study investigates the impact of novel ultrasonic-assisted squeeze casting parameters on the fabrication of AA2014/Al2O3 nanocomposites using the Taguchi Grey response surface methodology. The experiments were carried out using Taguchi's L16 orthogonal array, with five different controllable parameters of ultrasonic-assisted squeeze casting process such as ultrasonic power (1.5–2.25 kW), ultrasonic time (4–16 min.), pouring temperature (700–850 °C may result in premature solidification), squeeze pressure (50–200 MPa) and wt % of reinforcement (1-4). The process's performance measures included hardness, ultimate tensile strength, percentage of elongation and grain size. The microstructure of the nanocomposites was investigated using optical microscopy, high-resolution scanning electron microscopy and X-ray diffraction technique. The multiple responses were converted into a single Grey relational grade, which was then used in modelling and optimization using the response surface methodology. Analysis of variance and 3D surface plots were generated to investigate the most important parameters affecting the quality of AA2014/Al2O3 nanocomposites. The results showed that the optimum parameter settings were ultrasonic power of 2.2489 kW, ultrasonic time of 15.91min, pouring temperature of 700.67 °C, squeeze pressure of 41 MPa and wt % of reinforcement of 1.85. The results of TGRSM demonstrated that ultrasonic power had the strongest correlation with responses, with significant improvements in UTS and grain size. The confirmation experiment revealed an improvement of 0.201 in GRG. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) driven by electrocatalytic water splitting is attaining prevalent attention for the manufacturing of clean and green hydrogen energy. Herein, we report the simple one-step hydrothermal synthesis of cobalt sulfide nanoflakes decorated with reduced graphene oxide (CoS/rGO) nanocomposites as an effective electrode material for HER. The CoS/rGO nanocomposites exhibited the rGO nanosheet-decorated hierarchically interconnected CoS nanoflakes structure. The CoS/rGO nanocomposites exhibited an excellent HER activity with a low overpotential of 371 mV and a small Tafel slope of 103 mV/dec. More interestingly, the catalytic stability of CoS/rGO nanocomposites is comparatively higher than the pristine CoS NFs. These results suggest that the facile nanocomposites of CoS/rGO could be a prominent catalytic material for effective green hydrogen production. [Display omitted] • Hierarchical CoS/rGO nanocomposites were successfully synthesized via facile hydrothermal method. • The CoS/rGO nanocomposites exhibited high specific surface (20.54 m2/g) with large porosity. • CoS/rGO nanocomposites exhibited the excellent HER activities in 1 M KOH. • CoS/rGO nanocomposites exhibited a lower overpotential of 371 mV at 10 mA/cm2. [ABSTRACT FROM AUTHOR]

In the present study, a facile and simple hydrothermal technique was employed for the preparation of reduced graphene oxide (rGO) incorporated NiCo 2 S 4 and analyzed the hydrogen evolution reaction (HER) activity in alkaline media. The face centered cubic crystal structure is confirmed from the X-ray diffraction analysis and hexagonal cage like structure of NiCo 2 S 4 was visualized by FESEM analysis. With the increased number of facets in hexagonal cage structure, the electrochemical-active surface area (ECSA) gets increased, and the HER performance gets increased for bare NiCo 2 S 4. The additional ECSA is caused by the existence of rGO in the case of ternary nanocomposite (rGO-NiCo 2 S 4). The obtained small over potential (370 mV) and small Tafel slope (139 mV/dec) proves the excellent HER activity of rGO-NiCo 2 S 4 nanocomposite. The optimized rGO-NiCo 2 S 4 as excellent HER electrocatalyst provides a highly stable polarization curve up to 10 h and it can be more useful to replace the high-cost platinum noble electrocatalyst. [Display omitted] • A simple one step hydrothermal method was adopted to prepare pure and rGO incorporated NiCo 2 S 4. • A hexagonal cage like structure provides the large number of facet as well as high electrochemical-active surface area. • A small over potential of 370 mV and a small Tafel slope of 139 mV/dec was realized at 10 mA/cm2. [ABSTRACT FROM AUTHOR]