Thermal, physical properties and flammability of silane treated kenaf/ pineapple leaf fibres phenolic hybrid composites

Silane treated pineapple leaf fibre (PALF) and kenaf fibre were analyzed by Thermogravimetric analysis (TGA) that indicated the treated hybrid composite showed better thermal stability as compared to untreated hybrid composites. Dynamic mechanical analysis was carried out to evaluate the storage modulus (E′), loss modulus (E″), and tan delta as a function of temperature. Storage modulus of treated hybrid composites displayed highest storage and loss modulus as in comparison of untreated hybrid composites. The peak heights of tan α were highest in treated hybrid composites. Cole-Cole analysis was also carried out to understand the phase behaviour of the composite samples. Thermal mechanical analysis was used to study mechanical stability of hybrid composites in the presence of temperature. The effect of different fibre ratios in hybridization on density, void content, water absorption (WA), thickness swelling (TS) of PALF/KF hybrid composites were also analyzed. Treated hybrid composites were not very affective to improve the flammability of PALF/KF hybrid composites. The overall results showed that treated PALF/KF/phenolic hybrid composites improved the thermal and dynamic mechanical properties over untreated PALF/KF hybrid composites

Magnesium hydroxide reinforced kenaf fibers/epoxy hybrid composites: mechanical and thermomechanical properties

The present article deals with the fabrication of magnesium hydroxide (MH) filler reinforced kenaf/epoxy hybrid composites with different loading (10%, 15%, 20% and 25% by wt). Tensile, impact, flexural, morphological, thermal stability and dynamic mechanical properties of the developed MH/kenaf/epoxy hybrid composites were evaluated and compared. The analysis of the results revealed that the incorporation of the stiff MH particles into the kenaf/epoxy composites enhanced their tensile, flexural and impact properties, as well as their residual content. Enhancement in both storage (E′) and loss (E″) moduli, as well as a considerable decrease in damping factor (Tan δ), was observed in the hybrid composites, compared to the kenaf/epoxy composites. Moreover, a remarkable improvement in properties was noticed for the 20% MH hybrid composites, which was ascribed to better dispersion and interfacial interaction between the kenaf fibers and the epoxy within composites, enabling more efficient interfacial stress transfer. Overall, the 20% MH/kenaf/epoxy hybrid composites presented better mechanical strength, thermal stability and dynamic properties compared to the rest of the hybrid composites developed in this study

A New CuSe-TiO2-GO Ternary Nanocomposite: Realizing a High Capacitance and Voltage for an Advanced Hybrid Supercapacitor

A high capacitance and widened voltage frames for an aqueous supercapacitor system are challenging to realize simultaneously in an aqueous medium. The severe water splitting seriously restricts the narrow voltage of the aqueous electrolyte beyond 2 V. To overcome this limitation, herein, we proposed the facile wet-chemical synthesis of a new CuSe-TiO2-GO ternary nanocomposite for hybrid supercapacitors, thus boosting the specific energy up to some maximum extent. The capacitive charge storage mechanism of the CuSe-TiO2-GO ternary nanocomposite electrode was tested in an aqueous solution with 3 M KOH as the electrolyte in a three-cell mode assembly. The voltammogram analysis manifests good reversibility and a remarkable capacitive response at various currents and sweep rates, with a durable rate capability. At the same time, the discharge/charge platforms realize the most significant capacitance and a capacity of 920 F/g (153 mAh/g), supported by the impedance analysis with minimal resistances, ensuring the supply of electrolyte ion diffusion to the active host electrode interface. The built 2 V CuSe-TiO2-GO||AC-GO||KOH hybrid supercapacitor accomplished a significant capacitance of 175 F/g, high specific energy of 36 Wh/kg, superior specific power of 4781 W/kg, and extraordinary stability of 91.3% retention relative to the stable cycling performance. These merits pave a new way to build other ternary nanocomposites to achieve superior performance for energy storage devices

Design and Development of Defect Rich Titania Nanostructure for Efficient Electrocatalyst for Hydrogen Evolution Reaction in an Acidic Electrolyte

Cost-effective, efficient and stable electrocatalyst for water splitting in the acidic electrolyte medium has been developed. The acidic electrolyte could be a support for the high purity hydrogen production via water splitting. Accordingly, we have prepared the defect-rich titania nanostructure via electrochemical anodization and cathodization routes using the titanium plate, which showed highly effective and durable electrocatalyst of hydrogen evolution reaction (HER) in an acidic medium. This hybrid compound showed a low onset potential of −0.17 V for HER with a current density of −150 mA cm−2 in 1 M H2SO4. Moreover, the stability test has been performed with the defect-rich titania nanostructure as cathode for 6 h in the two electrodes system. © 2021 The Author(s).The authors extend their appreciation to the Deanship of Scientific Research, King Saud University for funding this work through Research Group no RG-1441-043 and funded by the Taif University Researchers Supporting Project number (TURSP-2020/04), Taif University, Taif, Saudi Arabia. One of the author Dr G. Murugadoss would like to thank Chancellor, President and Vice Chancellor, Sathyabama Institute of Science and Technology, Chennai for providing lab facilities and encouragement

Mechanical, thermal and microstructural characteristics of cellulose fibre reinforced epoxy/organoclay nanocomposites

Epoxy nanocomposites reinforced with recycled cellulose fibres (RCFs) and organoclay platelets (30B) have been fabricated and investigated in terms of WAXS, TEM, mechanical properties and TGA. Results indicated that mechanical properties generally increased as a result of the addition of nanoclay into the epoxy matrix. The presence of RCF significantly enhanced flexural strength, fracture toughness, impact strength and impact toughness of the composites. However, the inclusion of 1 wt.% clay into RCF/epoxy composites considerably increased the impact strength and toughness. The presence of either nanoclay or RCF accelerated the thermal degradation of neat epoxy, but at high temperature, thermal stability was enhanced with increased char residue over neat resin. The failure micromechanisms and energy dissipative processes in these nanocomposites were discussed in terms of microstructural observations

Use of Fe3O4 Nanoparticles and Ultrasound-assisted Dispersive Liquid-liquid Microextraction of Lead in Water, Tobacco, and Fertilizer Samples for FAAS Determination

A Fe3O4 nanoparticle and ultrasonic coupled dispersive liquid-liquid microextraction (NPsU-DLLME) method was developed for the preconcentration of lead from water, tobacco, and fertilizer samples. Imidazole-2,4-dicarboxylic acid was used as the chelating agent and carbon tetrachloride as the extractor solvent. Addition of certain amounts of Fe3O4 nanoparticles and specific exposure periods to ultrasonic waves were optimized. Maximum recovery (%) was obtained using the following conditions: 17.5 mL sample volume, sample pH 6, 100 mu L of carbon tetrachloride as the extraction solvent, 70 mu L of ethanol as the dispersing solvent, 100 mu L of 0.1% imidazole-2,4-dicarboxylic acid as the chelating agent, 100 mu L of a 0.1% Fe3O4 nanoparticle suspension, and a 1-minute exposure to ultrasonic waves. This method was validated using an SPS-WW2 Wastewater certified reference material. The limit of detection (LOD) was 5.3 mu g L-1, the limit of quantification (LOQ) 15.8 mu g L-1, and the relative standard deviation (RSD) 2.6%. The method was applied to the determination of lead in some water, tobacco, and fertilizer samples

1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) for the separation-enrichment and flame atomic absorption spectrometric detection of copper and lead in hair, water, and food samples

A novel enrichment-separation procedure based on solid phase extraction of copper(II) and lead(II) at ultratrace levels on 1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) has been established. The effective critical parameters like pH and eluent type etc. on the quantitative recoveries of the analyte elements were optimized. The matrix effects are also investigated. The procedure was validated by analysing water certified reference materials and addition-recovery tests. The relative standard deviation of the presented procedure was below 10%. The application of the presented solid phase extraction procedure was successfully performed for copper and lead determination in some food and water samples