Electron Microscopy Investigations Research Articles

Lubricity performance of Jatropha oil incorporated PTFE and h-BN as additives for electric vehicles transmission lubrication

Purpose Concerns over the pollution caused by internal combustion vehicles have increased owing to population and industrialization increment. Addressing the confrontations, the demand for electric vehicles (EVs) as a combustion engine substitute became necessary in responding to environmental worries from internal combustion. The development of bio lubricant in lubricating the sliding parts of EVs is required to maintain the sustainability idea and to improve the system performance, which this research tends to explore. Design/methodology/approach In this research, the enhancement of base Jatropha oil was done using polytetrafluoroethylene (PTFE) and hexagonal boron nitrate (h-BN) as additives. Different characterization was conducted on the new formulation to ascertain its anticorrosion tendency. The wear and friction behavior of the formulations on the tribo-pairs surfaces in contact were investigated using ball on flat tribometer to determine their tribological responsiveness as mineral lubricant alternative. To explore the surface topography, surface profilometer, scanning electron microscope and energy dispersive X-ray investigations were PTFE, lubrication and EV carried out. Findings The test’s input parameters were EVs’ usual load and sliding speed, and the addition concentrations for PTFE were 0.3 Wt.%, 0.4 Wt.%, 0.5 Wt.% and 0.6 Wt.%, whereas h-BN were 0.4 Wt.%, 0.8 Wt.% and 1.2 Wt.%, respectively. The study on corrosion demonstrated resistance when applied PTFE and h-BN additives in Jatropha oil. The analysis revealed that 0.5 Wt.% PTFE + 0.8 Wt.% h-BN concentrations significantly improved the tribological characteristics when compared to the base Jatropha oil. The application of formulations yielded percentage reduction of 8.67%, 10.98%, 7.34% and 7.35%, respectively, for 0.5% poly + 0.5% h-BN, 0.5% poly + 0.6% h-BN, 0.5% poly + 0.7% h-BN, 0.5% poly + 0.8% h-BN against base Jatropha oil under 20 N. Originality/value The formulation of PTFE and h-BN for electric transmission with wear and friction effects was accomplished in this paper. The mechanism of particle diffusing at the sliding contact on tribological behavior could be examined based on the created model of operation. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0235/

Oxidative stress-induced cytotoxicity of HCC2998 colon carcinoma cells by ZnO nanoparticles synthesized from Calophyllum teysmannii

The field of green synthesis, namely using plant extracts for the production of metal nanoparticles, is rapidly gaining traction. Therefore, this study investigated the process of producing zinc oxide nanoparticles (ZnO NPs) using a water-based extract derived from the stem bark of Calophyllum teysmannii. Notably, this is the first documented utilization of this particular plant source. The presence of a distinct Ultraviolet-Visible (UV-Vis) absorption peak at 372 nm provided evidence for the creation of ZnO nanoparticles. The X-ray Diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM) investigations indicated that the nanoparticles exhibited sizes ranging from 31.5 to 59.9 nm and had spherical morphologies. Energy Dispersive X-ray Diffractometer (EDX) analysis verified the elemental composition of the ZnO nanoparticles, whereas the Fourier Transform Infrared (FTIR) spectra showed clear peaks, demonstrating their production. The FTIR examination of the C. teysmannii extract revealed peaks at around 3370 cm− 1, indicating the presence of phenolic compounds. These chemicals are likely responsible for the reduction and stabilization of the ZnO NPs. The high-resolution X-ray Photoelectron Spectroscopy (XPS) spectra clearly revealed separate peaks corresponding to Zn 2p and O 1s, providing confirmation of the chemical states and bonding contexts. The Raman Spectroscopy analysis revealed a distinct peak at around 425 cm⁻¹, confirming the presence of the wurtzite structure. The harmful effects of ZnO nanoparticles on HCC2998 (a kind of human colon cancer) and Vero (a type of monkey kidney epithelial) cells were evaluated using 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT), dichlorodihydrofluorescein diacetate (DCFH-DA), and boron-Dipyrromethene (BODIPY) assays. The cancer cells underwent cell death due to oxidative stress in a dose-dependent manner, as confirmed by microscopic and flow cytometry investigations.

Synthesis and Fungicidal Activities of Coumarin Derivatives as Succinate Dehydrogenase Inhibitors.

Succinate dehydrogenase inhibitors (SDHIs) have been developed to the fastest growing family of fungicides. To develop novel SDH inhibitors, twenty-seven novel non-amides coumarin derivatives were designed, synthesized and characterized .The bioassay revealed that most of the target compounds exhibited significant antifungal activity against Botrytis cinerea in vitro. Notably, compounds 1a and 2c with EC50 values of 0.92 μg/mL and 0.52 μg/mL, respectively，which were better than that of positive control chlorothalonil (EC50 =3.14 μg/mL).Moreover, in vivo antifungal assay results showed that compound 2c could observably inhibit the growth of B. cinerea on Kuerla pears with remarkable protective at a dosage of 200 μg/mL. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigation indicated that compound 2c significantly damaged the cell structures of B. cinerea mycelium. 3D-QSAR models were analyzed structure-activity relationships of all target compounds. Furthermore, molecular docking revealed that compound 2c was able to bind closely to the receptor protein of SDH. These results demonstrated that compound 2c may be potential candidate for novel SDH inhibitors.

Formation of B2 Phase and its Phase Stability in Equiatomic Al-Cu-Fe-Ni-Ti High Entropy Alloy

In the present investigation, we have synthesized a single-phase high-entropy alloy in Al-Cu-Fe-Ni-Ti system by melting of the individual metals using a radiofrequency induction furnace under an argon environment. The as-synthesized alloy shows the formation of a B2-type ordered phase with a lattice parameter of 0.289nm. The mechanical stability of this single phase high-entropy alloy was investigated under high-energy ball milling. The milling was performed at a speed of 400rpm for 10, 20, and 40h under a hexane medium with a ball-to-powder ratio of 40:1. The formation of nano crystallites (~ 10nm sizes) body centered cubic (BCC) phase (disordered B2) has been observed after 40h of ball milling, which has been confirmed by X-ray diffraction and transmission electron microscopic investigation. The equiatomic Al-Cu-Fe-Ni-Ti high entropy alloy structure is observed to be quite stable during mechanical milling up to 40h; only grain refinements and lattice strain accumulation were observed with milling time.

New trends in mycosynthesis of cellulose nanocrystals promoted by gamma irradiation of sugarcane bagasse

AbstractThe biological synthesis of cellulose nanocrystals (CNCs) involves utilizing cellulose-degrading microorganisms or their hydrolytic enzymes as catalysts for the controlled degradation of cellulose, yielding CNCs. Chemical synthesis of CNCs involves acid hydrolysis conducted for 45 min at 45 °C using sulfuric acid (64%). Neurospora intermedia (Assiut University Mycological Center (AUMC) 14,359), Fusarium verticillioides (AUMC 14360), and Rhizopus oryzae (AUMC 14361) were employed in the preparation of CNCs. Before both chemical and biological treatments, sugarcane bagasse (SCB) was irradiated with doses of 100, 200, and 300 kGy, enhancing the yield of nanocellulose from the cellulosic feedstock. The resultant nanocellulose was initially assessed using UV–Vis spectroscopy, and the characterization was further refined through Dynamic Light Scattering analysis to delineate particle size distribution within the nanoscale and to evaluate stability. CNCs and chemically purified cellulose (CPC) displayed analogous Fourier Transform Infrared Spectroscopy but were markedly different from SCB. X-ray Diffraction patterns revealed a notably higher crystallinity of cellulose in nanocellulose, with larger crystallite dimensions compared to CPC and SCB. Transmission Electron Microscope investigations elucidated the morphology of the synthesized nanoparticles. In summary, the selection of F. verticillioides for nanocellulose production represents a promising and sustainable approach that combines effectiveness, environmental friendliness, and cost-efficiency in the synthesis of this valuable nanomaterial. Graphical abstract

Distribution and volume of mitochondria in alveolar epithelial type 1 cells in infant and adult human lungs

Alveolar epithelial type I (AE1) cells with their wide spatial expansion form approximately 95% of the outer surface area of the air-blood barrier inside the lung. Serial block-face scanning electron microscopy (SBF-SEM) investigations led to the hypothesis that AE1 cell mitochondria are preferentially distributed as aggregates in those parts of AE1 cells that are located above connective tissue pillars between capillaries, thus not increasing the thickness of the diffusion distance for oxygen and carbon dioxide. Furthermore, it was hypothesised that postnatal development requires adapting the amount and distribution of mitochondria in AE1 cells. Human lung samples from three infant (26 and 30 days, 6 months) and three adult (20, 39 and 40 years) samples were investigated by light microscopy, transmission electron microscopy and stereology. The volume fraction of mitochondria was similar in infant and adult lungs with a mean value of 6.3%. The ratio between mitochondrial profiles on top of capillaries or above connective tissue pillars was approximately 3:1 in infants and adults. However, regarding the volume of both cytoplasmic compartments, infants showed a higher number of mitochondrial profiles on top of capillaries while adults showed a higher number above connective tissue pillars. Samples of three additional adult lungs were analysed by confocal laser scanning microscopy. Again, mitochondria were not preferentially found as aggregates above connective tissue pillars. In conclusion, AE1 cell mitochondria were not preferentially found as aggregates, showed the same volume density in infants and adults but differed in distribution between the age groups.

In-situ transmission electron microscopy (TEM) investigation of the reduction process in graphene oxide

In-situ transmission electron microscopy (TEM) investigation of the reduction process in graphene oxide

CO2 Interaction Mechanism of SnO2-Based Sensors with Respect to the Pt Interdigital Electrodes Gap

The tuning sensitivity towards CO2 detection under in-field-like conditions was investigated using SnO2-sensitive material deposited onto Al2O3 substrates provided with platinum electrodes with interdigital gaps of 100 µm and 30 µm. X-ray diffraction, low-magnification and high-resolution transmission electron microscopy, and electrical and contact potential difference investigations were employed to understand the sensing mechanism involved in CO2 detection. The morpho-structural analysis revealed that the SnO2 nanoparticles exhibit well-defined facets along the (110) and (101) crystallographic planes. Complex phenomenological investigations showed that moisture significantly affects the gas sensing performance. The experimental results corroborated the literature evidence, highlighting the importance of Pt within the interdigital electrodes subsequently reflected in the increase in the CO2 sensing performance with the decrease in the interdigital gap. The catalytic efficiency is explained by the distribution of platinum at the gas-Pt-SnO2 three-phase boundary, which is critical for enhancing the sensor performance.

Efficiency Improvement on Indium Tin Oxide Films for Dye-Sensitized Solar Cell Using Oxygen Plasma by Bias-Magnetron RF Sputtering Process

Dye-sensitized solar cells (DSSCs) are among the most widely studied thin-film solar cells because of their cost-effectiveness, low toxicity, and simple fabrication method. However, there is still much scope for replacing current DSSC materials due to their high cost, low volume, and lack of long-term stability. Accordingly, indium tin oxide (ITO)-nanorod films were fabricated by electron (E)-beam evaporation using the glancing angle deposition method in this study. Then, the ITO-nanorod was treated with oxygen plasma via a bias-magnetron radio-frequency (RF) sputtering process to improve the efficiency of DSSCs under a varying gas flow rate of 20, 40, 60, 80, and 100 sccm. The field emission scanning electron microscopy (FE-SEM) investigation of the ITO film structure revealed that the obtained nanorod structures have slightly different diameters. At the same time, an increase in the oxygen flow rate resulted in a rougher film surface structure. In this, the lower sheet resistance was received because of rougher morphology. When comparing the DSSCs efficiency (η) test results, we found that at a gas flow rate of 100 sccm, the highest efficiency value showed 9.5%. On the other hand, the ITO-nanorod without plasma treatment exhibited the lowest η. Hence, plasma technology can be practically applied to improve the η of DSSC devices. This study will be a prototype of a highly advanced solar cell manufacturing method for the solar cell industry.

When to change needles during neuromodulator injections-An electron-microscopy investigation into needle tip deformation.

Neuromodulator injections are minimally invasive procedures performed across the globe. Despite their ubiquity, there is a dearth of information on whether and how needle tips used for neuromodulator procedures are deformed after repeated injections. We investigated the magnitude of needle tip deformation following sequential injection passes (3×, 5×, and 10×) during facial neuromodulator injections with three commonly used needle sizes (30G, 31G, and 32G). Neuromodulator was administered for four different aesthetic indications. Each collected needle was mounted and imaged in a Philips XL-30 Scanning electron microscope. Images were processed using ImageJ photo analysis software. Forty-five needle tips were investigated. When comparing the facial regions of interest, a statistically significant difference in deformation percentage was found when injecting 10× (p = 0.044) with greatest damage after injecting the glabella (38.4%), followed by lateral canthus (27.9%), forehead (27.5%), and midface (23.1%). Independent of facial region targeted, the mean percentage of needle deformation at 3× was 14.8%, at 5× 19.6%, and at 10× 29.2% with p < 0.001. Smaller needle size corresponded to smaller percentage of damage. Exchanging needles after more than five injection passes will minimize needle deformation and likely increase injection precision.

Staggering cytotoxic effects of manganese oxide nanoparticles from Bacillus thuringiensis

The current study describes the biological synthesis of manganese oxide nanoparticles from Bacillus thuringiensis, as well as their characterization, biological activity, and toxicity. Nanoparticles may be synthesized in multiple ways, but the biogenic process is the most environmentally friendly and cost-effective. The optical, structural, and crystalline properties of the nanoparticles were investigated. A distinctive peak at 246 nm with a band gap of 3.7eV indicates manganese oxide nanoparticle production. A strong peak at 563.09 cm−1 indicates Mn-O stretching in Fourier Transform Infrared Spectroscopy analysis. X-ray diffraction revealed that the crystalline grain size of manganese oxide nanoparticles was 11.23 nm. The agglomerated spherical shape is seen in the Scanning Electron Microscope and High-Resolution Transmission Electron Microscope investigations. The presence of manganese was verified by the EDAX. Manganese oxide nanoparticles have a significant zeta potential peak of −23.4 mV. This work explored the biological activity of manganese oxide nanoparticles, including antibacterial, anti-inflammatory, antioxidant, and biofilm inhibition studies. To investigate cytotoxicity, Allium cepa root tips are treated with manganese oxide nanoparticles.

Crystallization and Optical Behaviour of Nanocomposite Sol-Gel TiO2:Ag Films.

Sol-gel spin coating method was employed for depositing TiO2 and Ag-doped TiO2 films. The effects of Ag doping and the annealing temperatures (300-600 °C) were studied with respect to their structural, morphological, vibrational, and optical properties. Field Emission Scanning Electron microscopy (FESEM) investigation exhibited the grained, compact structures of TiO2-based films. Ag incorporation resulted in a rougher film surface. X-ray diffraction (XRD) results confirmed the formation of Ag nanoparticles and AgO phase, along with anatase and rutile TiO2, strongly depending on Ag concentration and technological conditions. AgO fraction diminished after high temperature annealing above 500 °C. The vibrational properties were characterized by Fourier Transform Infrared (FTIR) spectroscopy. It was found that silver presence induced changes in IR bands of TiO2 films. UV-VIS spectroscopy revealed that the embedment of Ag NPs in titania matrix resulted in higher absorbance across the visible spectral range due to local surface plasmon resonance (LSPR). Ag doping reduced the optical band gap of sol-gel TiO2 films. The optical and plasmonic modifications of TiO2:Ag thin films by the number of layers and different technological conditions (thermal and UV treatment) are discussed.

Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO3 nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO3 decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO3 formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO3 compared to MoO3. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO3. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO3 during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO3. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.

Diversity of attachment systems in heelwalkers (Mantophasmatodea) – highly specialized, but uniform

BackgroundHeelwalkers possess a highly modified tarsal attachment system. All extant species lift the distalmost tarsomere permanently off the substrate and primarily use their euplantulae for locomotion. The combination of a smooth adhesive pad (arolium) on the pretarsus and fibrillary attachment pads on the euplantulae offers valuable insights for translational approaches, but its infra-order diversity remains unexplored.ResultsWe explored the morphology of the tarsal attachment apparatus of Mantophasmatodea based on a representative taxon sampling spanning a large fraction of species of this group and compared morphological differences in the specialized morphology of this system across species and sexes. Our scanning electron microscope investigation of the tarsi of 11 species (52% of all described extant species) revealed an overall very consistent ground pattern and almost no specific adaptations. There are only minor, but mostly clade-specific differences in the shape of the adhesive setae on the tarsal euplantulae and in the morphology and density of the acanthae on the pretarsal arolium. Both features differ primarily between Austrophasmatidae in comparison to the remaining Mantophasmatodea taxa.ConclusionWe conclude that the strong specialization of the mantophasmatodean tarsal attachment sufficiently copes with the diversity of substrates the insects are exposed to.

Microstructural Evolution and High‐Temperature Tensile Properties of 15Cr‐Reduced Activation Ferritic Steel Processed by Hot Powder Forging of Mechanically Alloyed Powders

Reduced activation ferritic steels are being explored as possible cladding tube materials for nuclear reactors because of their low activation and excellent irradiation resistance. In the current investigation, reduced activation ferritic steel (Fe–15Cr–2W) is processed by mechanical alloying of elemental powders followed by hot powder forging. Mechanical alloying is carried out in a Simoloyer attritor mill (Zoz GmbH), after which the powders are placed in a mild steel can and forged at 1200 °C in H2 atmosphere. X‐ray diffraction and transmission electron microscopy (TEM) investigation reveal that 10 h of mechanical alloying is required to achieve complete dissolution of Cr and W in the Fe matrix powder. The relative density and hardness distribution of the forged slab is evaluated in longitudinal as well as transverse direction to optimize the powder forging operation. Electron backscatter diffraction analysis showed dynamic recrystallization to take place during the course of hot powder forging. Tensile tests are performed at room temperature as well as at elevated temperatures (600 and 700 °C). The yield strength and ultimate tensile strength at room temperature as well as at elevated temperatures are found to be higher than those reported in literature for reduced activation ferritic steels consolidated by other techniques.

A novel and sustainable approach to efficiently modify cotton material via a physical flash-explosion with sub- or SCF-CO2 as medium

A novel and eco-friendly approach to modify natural cotton fiber by flash-explosion with a sub- or supercritical fluid of carbon dioxide (sub- or SCF-CO2) for improving its structure and properties was constructed for the first time. The achieved results demonstrate that remarkable improvements in the coloration performance of cotton fiber by 71.1 % and the water retention by 1001.2 % against the control could be readily available by employing the flashily-explosion method at a recommended condition with 4-cycle explosion in sub- or SCF-CO2, and system temperature, fluid treatment duration and explosion number exhibited much more pronounced positive influences among all parameters. Additionally, minimal influences from the supercritical explosion on cotton fiber micronaire value, thermal property and tensile breaking strength were also observed. The scanning electron microscopy (SEM) and porosity investigations clearly show that plenty of micropores and/or strip fissures were formed on the fiber surfaces and their inner phases, and notably improved fiber surface area, pore volume and size were also obtained after a subsupercritical flash-explosion. Nuclear magnetic resonance hydrogen spectroscopy (1H NMR) and Fourier transform infrared spectroscopy (FT-IR) analysis disclose that numbers of hydrogen bonds between the fiber macrochains and/or from their intramolecular chains were broken by generating numerous free hydroxyl groups, which reasonably supported the improvements of the dye uptake behaviors and water retention properties, etc. The Energy-dispersive X-ray spectroscopy (EDS) analysis on the fiber cross-sections further confirms that a loosening of the inner aggregation structure of the cotton fiber was achieved after a flash explosion by significantly enhancing its coloration performance, etc. This innovative approach provides a promising idea and possibility as an alternative to chemical methods via mechanically and physically modifying fiber or other materials with sub- or SCF-CO2 fluid in an eco-friendly and sustainable manner.

Synthesis and characterization of core–shell magnetic molecularly imprinted polymer nanocomposites for the detection of interleukin-6

Interleukin-6 (IL-6) belongs to the cytokine family and plays a vital role in regulating immune response, bone maintenance, body temperature adjustment, and cell growth. The overexpression of IL-6 can indicate various health complications, such as anastomotic leakage, cancer, and chronic diseases. Therefore, the availability of highly sensitive and specific biosensing platforms for IL-6 detection is critical. In this study, for the first time, epitope-mediated IL-6-specific magnetic molecularly imprinted core–shell structures with fluorescent properties were synthesized using a three-step protocol, namely, magnetic nanoparticle functionalization, polymerization, and template removal following thorough optimization studies. The magnetic molecularly imprinted polymers (MMIPs) were characterized using dynamic and electrophoretic light scattering (DLS and ELS), revealing a hydrodynamic size of 169.9 nm and zeta potential of +17.1 mV, while Fourier transform infrared (FTIR) spectroscopy and fluorescence spectroscopy techniques showed characteristic peaks of the polymer and fluorescent tag, respectively. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) investigations confirmed the successful encapsulation of the magnetic core within the ca. 5-nm-thick polymeric shell. The MMIP-based electrochemical sensing platform achieved a limit of detection of 0.38 pM within a linear detection range of 0.38–380 pM, indicating high affinity (dissociation constant KD = 1.6 pM) for IL-6 protein in 50% diluted serum samples. Moreover, comparative investigations with the non-imprinted control polymer demonstrated an imprinting factor of 4, confirming high selectivity. With multifunctional features, including fluorescence, magnetic properties, and target responsiveness, the synthesized MMIPs hold significant potential for application in various sensor techniques as well as imaging.

Palladium-Functionalized Nanostructured Nickel-Cobalt Oxide as Alternative Catalyst for Hydrogen Sensing Using Pellistors.

To meet today's requirements, new active catalysts with reduced noble metal content are needed for hydrogen sensing. A palladium-functionalized nanostructured Ni0.5Co2.5O4 catalyst with a total Pd content of 4.2 wt% was synthesized by coprecipitation to obtain catalysts with an advantageous sheet-like morphology and surface defects. Due to the synthesis method and the reducible nature of Ni0.5Co2.5O4 enabling strong metal-metal oxide interactions, the palladium was highly distributed over the metal oxide surface, as determined using scanning transmission electron microscopy and energy-dispersive X-ray investigations. The catalyst tested in planar pellistor sensors showed high sensitivity to hydrogen in the concentration range below the lower flammability limit (LFL). At 400 °C and in dry air, a sensor response of 109 mV/10,000 ppm hydrogen (25% of LFL) was achieved. The sensor signal was 4.6-times higher than the signal of pristine Ni0.5Co2.5O4 (24.6 mV/10,000 ppm). Under humid conditions, the sensor responses were reduced by ~10% for Pd-functionalized Ni0.5Co2.5O4 and by ~27% for Ni0.5Co2.5O4. The different cross-sensitivities of both catalysts to water are attributed to different activation mechanisms of hydrogen. The combination of high sensor sensitivity to hydrogen and high signal stability over time, as well as low cross-sensitivity to humidity, make the catalyst promising for further development steps.

Development and Characterization of Ethylene‐Vinyl Acetate‐Graphene Nanocomposites

AbstractThe prospective applications of carbon graphene nanoplatelets (GNPs) reinforced ethylene vinyl acetate (EVA) nanocomposites in flexible electronics, energy storage devices, and thermal management systems have attracted a lot of attention. These nanocomposites offer an effective solution for enhancing the electrical conductivity of interfacing materials in electronic systems and addressing issues related to thermal management. GNPs that possess excellent thermal conductivity of 2000–4000 W m−1 K−1 and an electrical conductivity of 107 S m−1 are utilized in this investigation. The homogeneous dispersion of nanofiller and the effective load transfer between components through strong filler/polymer interfacial interactions are essential for the creation of multifunctional polymer nanocomposites. Particularly, their electrical conductivity and dielectric properties are highlighted in this study, with an emphasis on the synthesis and characterization of nanocomposite materials. This work investigates the utilization of graphene nanocomposites in EVA using a melt‐mixing technique assisted by sonication to fabricate multifunctional composites. Incorporating different weight percentages of GNPs (ranging from 0.1 to 0.4 wt.%) within the polymer matrix is carried out. In the present study, the nanocomposites are characterized by scanning electron microscopy investigation and impedance spectrum analysis. The distinctive characteristics of the AC electrical transport in nanocomposites are investigated between 10 Hz and 1 MHz. Excellent interfacial compatibility has been demonstrated by the homogenous distribution of GNPs within the matrix, confirmed by SEM examination. These EVA nanocomposites demonstrate improved electrical conductivity, thereby rendering them very useful for energy storage applications, such as electronic capacitors, wherein supports with a significant dielectric constant and minimal dielectric loss are required.

INVESTIGATION OF WETTABILITY, ANTIBACTERIAL ACTIVITY, THERMAL INSULATION, AND MECHANICAL CHARACTERISTICS OF ELASTOMER BLEND ADHESIVES WITH HIGH-DENSITY FIBERBOARD WOOD AND ALUMINUM

Attention has recently been given to finding alternative and sustainable raw material sources for wood and metal adhesives, such as polyvinyl alcohol (PVA), corn starch (CS), arabic gum (AG), and dextrins (D). Modifying polymer dispersion using unique substances, such as modifying reactive elastomer liquid (EL) using PVA, CS, AG, or D results in sufficiently moisture-resistant adhesive joins. In the present study, the physical characteristics of EL/blended with the natural polymers PVA, CS, AG, and D, based on high-density fiberboard (HDF) wood and aluminum (Al) adhesives and coatings, were investigated and compared to those of pure EL. The EL was blended with PVA, CS, AG, or D at a ratio of 60/40 (w/w) to form EL/blends. The chemical structures, surface and interface morphology, adhesion strengths (including shear strength and pull-off strength), surface roughness, wettings, color intensity, and thermal insulation of the prepared EL and EL/blends were investigated. A scanning electron microscopy (SEM) investigation confirmed filler dispersion and adhesion between the blends, and coated HDF wood, or Al. The developed EL/AG blend had a pull-off strength of 144±5 and 102±3 MPa and a shear strength of 771±11, and 52±3 N with HDF wood and Al substrate, respectively. The EL/PVA blend had a maximum surface roughness value 4.57 µm, and its average water contact angle (WCA) was 85.6°. A plasma jet was used to treat the surface roughness and hence the wettability of the pure EL and the EL/blends, for example, plasma treatment decreased the roughness of the EL/AG blend from 4.36 to 3.28 μm. WCA, and hence wettability, was also significantly influenced by plasma treatment, for example, plasma treatment decreased the WCA of the pure EL from 71.7±0.4° to 30.7±0.7°. The lightness value of the EL/blends was less than that of the pure EL, indicating that (the color adhesives have darkened). Similarly, the yellowness-blueness and redness-greenness values of the EL/blends were greater than those of the pure EL,( rendering the blended adhesives more reddish and bluish). The EL/AG blend was found to have a minimum thermal conductivity (of 0.27 W/m.K), indicating maximum insulation.