Al2O3 Nanofiller Research Articles

Color stability, surface, and physicochemical properties of three-dimensional printed denture base resin reinforced with different nanofillers

Various materials have been introduced for the three-dimensional (3D) printing of dentures. In this study, the color stability and surface and physicochemical properties of 3D-printed denture base resins with four types of nanofiller particles were evaluated. Al2O3, ZnO, CeZr, and SiO2 nanofillers were added to a 3D printable denture base-resin matrix and subjected to digital light processing. The specimens were immersed in Coke, coffee, black tea, or distilled water for 6 days. For the assessment of color differences, 6 samples were analyzed using a spectrophotometer. In a separate investigation, surface properties of 10 samples were examined, while a different set of 6 samples was used to analyze water sorption and solubility. All experimental groups exhibited higher color stability in Coke than the control group. However, the groups containing ZnO and CeZr had lower color stability in coffee and black tea than the control group. Moreover, they had agglomerated nanofillers and lower gloss than the control group. Compared with that of the control group, the contact angle of the CeZr group and microhardness of the ZnO group were not significantly different. Water sorption was higher in the Al2O3 group, whereas the solubility of the experimental and control groups was not statistically significant. The results demonstrated the significant effect of ZnO and CeZr nanofillers on the color stability of the dentures when exposed to discoloring beverages. These results will facilitate the development of fillers that enhance the resistance of 3D printed denture base resins to discoloration in the oral environment.

Retracted: Biosynthesis-Based Al2O3 Nanofiller from Cymbopogon citratus Leaf/Jute/Hemp/Epoxy-Based Hybrid Composites with Superior Mechanical Properties.

[This retracts the article DOI: 10.1155/2023/9299658.].

Study the Al2O3 nano-fillers performances of metallic hollow microlattice material as a heat insulation on the high-temperature

Hollow microlattice material is a kind of excellent heat insulation material due to its special microstructural characteristics and ultra-low relative density. However, the possibility of oxidation at the temperature higher than 500℃ limits its application in the high-temperature insulation fields, such as rockets and aircraft engines. In order to overcome this obstacle, this study successfully prepared nano-Al2O3 reinforced metallic hollow microlattice materials with an equivalent density of 26.5 mg/cm3. Heat insulation tests and thermogravimetric (TG) experiments were also carried out to investigate the thermal performances of the Al2O3 reinforced metallic hollow microlattice materials, while the effect of the concentration of the Al2O3 was also investigated in accordance with the comparative tests. The results indicate that the Al2O3 plays a significant role in hindering the high-temperature oxidation of hollow microlattice material, especially with Al2O3 concentration in the range of 2 g/L to 4 g/L, and the heat insulation performance can be improved by 13.9%.

Solid electrolyte membranes with Al2O3 nanofiller for fully solid-state Li-ion cells

Solid electrolyte membranes with Al2O3 nanofiller for fully solid-state Li-ion cells

Nanofiller‐Based Novel Hybrid Composite Membranes for High‐Capacity Lithium‐Sulfur Batteries

AbstractHerein, Al2O3 nanofiller‐reinforced lithiated Nafion:Aquivion hybrid composite ion‐exchange membranes have been produced by mixing lithiated Nafion and Aquivion ionomers. After the electrochemical tests, the Li‐Naf : Li‐Aqu/1 : 2 compound, which offers the best electrochemical performance, was selected. Lithiated hybrid composite membranes were obtained by reinforcing Al2O3 nanofillers at different rates to this composition. The ion exchange capacity, polysulfide transition and solvent uptake of the obtained membranes were investigated and the structural characterizations were applied by tensile test, Fourier Transform Infrared Spectroscopy (FTIR), X‐ray Diffraction (XRD), and membrane morphology was examined with Field Emission Scanning Electron Microscopy (FESEM). For performing the electrochemical tests, CR2032 half cells were designed. Electrochemical characterizations of the produced membranes were carried out by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), and galvanostatic charge‐discharge tests. The best electrochemical performance was achieved with 868 mAhg−1 discharge capacity and 63.8 % capacity retention when Li‐Naf : Li‐Aqu/1 : 2 composition was reinforced with 1 % Al2O3 nanofiller. As a result, lithiated hybrid composite ion exchange membranes could prevent the shuttle effect of polysulfides while enabling the passing of Li ions for high‐performance Li−S batteries.

Al2O3 Nano filler’s impact on electrical, mechanical, thermal, microstructural and the chemical characteristics of liquid silicone rubber for composite insulators

This study examines the function of Al2O3 nanofiller in liquid silicone rubber (LSR) for the purpose of outdoor insulation. Several characteristics, including structural (Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), physical (density), mechanical (tensile, tear, percentage elongation at break, and shore A hardness), thermal (thermal conductivity, thermo gravimetric analysis (TGA)), electrical (dielectric constant, dielectric breakdown strength, DC volume resistivity, arc resistance, and recovery of hydrophobicity), although chemical (immersion of samples for 72 h in NaCl, HCl, and H2SO4 solutions and measurement of sample weight and PH of the solution before and after immersion) were investigated after the addition of Al2O3 nanofiller with different compositions, such as 5, 10, and 15 weight percentages. In comparison to pure LSR, it was discovered that the inclusion of nano Al2O3 particles enhanced the material’s density by 11%, thermal conductivity by 12%, dielectric constant by 24%, DC volume resistivity by 2%, arc resistance by significantly 1205%, dielectric breakdown strength by 54%, and hydrophobicity. Other improvements include a 7% rise in tensile strength, a 23% rise in tear strength, a 17% rise in hardness, and an 18% reduction in percentage elongation at break when compared to pure LSR for the composite samples. Mechanical qualities are affected by the curing process duration. More specifically, we discovered there is a proportionality relationship between the tensile strength and the elastic modulus. Findings of the chemical examination revealed that the composites have corrosion resistance in the form of negligible weight change in the sample when exposed to salt and acid solutions. The combination of these exceptional qualities makes Al2O3 composites appealing within an insulating materials realm.

Optical properties of functional Al2O3 nano-filler in eco-friendly PVA polymer for flexible optoelectronic devices

This article has attempted to establish eco-friendly organic PVA/Al2O3 nanocomposite membranes and estimate the effectiveness of different additives (1, 2, and 3 wt%) of alumina (Al2O3) nano-filler in PVA matrix on their structural and optical properties for establishing their suitability in photonic applications. Al2O3 nano-filler dispersed in the PVA matrix has been synthesized via the solvent casting technique. The structure of synthesized PVA/Al2O3 nanocomposite membranes has been characterized by Fourier transform-infrared (FTIR), Raman spectroscopy, and X-ray diffraction (XRD). Upon introducing the Al2O3 nano-filler in the PVA matrix, the self-hydrogen bonding between the PVA chains was weakened while hydrogen bonding with Al2O3 was generated. In addition, optical, dielectric, and dispersion analysis suggested that even though the Al2O3 nano-filler in PVA/Al2O3 nanocomposite membranes aided in regularly folding the PVA polymer chains. Moreover, formed new structural defects, disorders, and impurities can be used for tuning the PVA/Al2O3 nanocomposites for optoelectronic applications and for making efficient absorbents for environmental treatments.

Experimental and Numerical Investigations on the Effect of MWCNT-COOH and Al2O3 Hybrid Nanofillers Dispersed CFRP Laminates Subjected to Projectile Impact

Although carbon fiber-reinforced polymer (CFRP) composites have excellent intrinsic mechanical properties, they are vulnerable to impact loads because of their weak inter-laminar fracture toughness, which results in delamination damage. This study presents a novel hybrid nanofiller combination of multi-walled carbon nanotubes (MWCNT) and alumina nanoparticles (Al2O3) to determine improvements in the impact resistance of CFRP laminate. The projectile impact experimental study is carried out on 140 mm × 140 mm × 1.5 mm CFRP laminate with spherical and conical nose shape projectiles. The numerical study of the test plate consisting of six layers is performed, in which each layer is modeled using a shell element and connected through tiebreak contact. Using the Cowper–Symonds equation to determine the dynamic mechanical properties, the numerical validation is established considering the strain rate effect. The results, such as residual velocity, damage area, ballistic limit velocity and delamination obtained from numerical analysis, are compared with the experimental observations. In laminates with hybrid nanofillers, residual velocity decreased by 20% and 9% when spherical and conical projectiles were impacted, respectively. The study indicates that 0.1 wt% MWCNT + 1 wt% Al2O3 nanofiller concentration embedded CFRP offers better resistance against spherical and conical projectile impact.

Effect of Al2O3 and SiC Nano-Fillers on the Mechanical Properties of Carbon Fiber-Reinforced Epoxy Hybrid Composites

Polymeric nanocomposites are an emerging research topic, as they improve fiber-reinforced composites’ thermo-mechanical and tribological properties. Nanomaterials improve electrical and thermal conductivity and provide excellent wear and friction resistance to the polymer matrix material. In this research work, a systematic study was carried out to examine the tensile and hardness properties of a carbon fiber epoxy composite comprising nano-sized Al2O3 and SiC fillers. The study confirms that adding nano-fillers produces superior tensile and hardness properties for carbon fiber-reinforced polymer composites. The amount of filler loading ranged from 1, 1.5, 1.75, and 2% by weight of the resin for Al2O3 and 1, 1.25, 1.5, and 2% for SiC fillers. The maximum tensile strength gain of 29.54% and modulus gain of 2.42% were noted for Al2O3 filled composite at 1.75 wt.% filler loading. Likewise, enhanced strength gain of 25.75% and 1.17% in modulus gain was obtained for SiC-filled composite at 1.25 wt.% filler loading, respectively. The hardness property of nano-filled composites improved with a hardness number of 47 for nano-Al2O3 and 43 for nano-SiC, respectively, at the same filler loading.

Influence of thermally shocked GO_CuO and GO_Al2O3 nanofillers on the optical and dielectric properties of PVA-based nanocomposites

Influence of thermally shocked GO_CuO and GO_Al2O3 nanofillers on the optical and dielectric properties of PVA-based nanocomposites

Tribological Characterization of Epoxy Hybrid Composites Reinforced with Al2O3 Nanofiller

The addition of fillers to polymer composites induces a positive influence on the mechanical and tribological properties of the hybrid composites. These properties can be validated for possible uses such as automobile, construction, shipping, aerospace, sports equipment, electronics, and biomedical domains. In the present research, epoxy matrix reinforced with nylon-6 fibers and glass fibers were prepared using the solution blend technique. Alumina nanoparticles are added as fillers to enhance the properties of epoxy hybrid composites. The large surface area of interaction of nanofillers exhibits better adhesion between matrix and fibers of composites, and it significantly affects the various properties of composites. The tribological characteristics of fabricated epoxy hybrid composites were evaluated under various parameters and conditions. The results revealed that the addition of nanofiller significantly reduces the wear loss of epoxy hybrid nanocomposites. The wear resistance of epoxy hybrid composites increased with increase in addition of nanofiller up to 1.0%, and it slightly decreased with the further addition of filler. The Taguchi analysis was carried out for the least coefficient of friction and specific wear rate. The analysis found that the specific wear rate and coefficient of friction mainly depend on load, followed by speed and nanofiller. The fractured and worn surface of Al2O3-filled epoxy hybrid composites was analysed using SEM.

Polyimide dielectric nanocomposites containing functional nanofillers based on multilayer structure: Design, preparation, and properties

AbstractPolyimide (PI) dielectric nanocomposites containing functional nanofillers based on layered structure (single‐layer: BT@Al2O3@PI, double‐layer: PI/BT@Al2O3@PI, three‐layer: PI/BT@Al2O3@PI/PI) were designed and prepared by using PI as matrix, barium titanate (BT)@alumina (Al2O3) as nanofillers through in‐situ polymerization compounding technology. FTIR tests indicated that PI and PI dielectric nanocomposites have been synthesized successfully. The molecular mass of BaTiO3@Al2O3@PAA oligomer was higher than that of pure PAA when BT and Al2O3nanofillers were incorporated simultaneously, as verified by GPC and intrinsic viscosity tests. XRD analysis showed that the addition of nanofillers destroyed the order of PI molecular structure and reduced the arrangement density of PI molecular chains. Both FESEM and HRTEM observations showed that the nanofillers were homogeneously dispersed in the PI matrix, contributing to the property improvements of PI dielectric nanocomposites. TGA results indicated that adding nanofillers improved the thermal stability and heat resistance of PI dielectric nanocomposites. The dielectric constant of PI/BT@Al2O3@PI double‐layer nanocomposites was between the single‐layer nanocomposites and pure PI. Due to the effective medium theory, the dielectric constant of three‐layer PI/BT@Al2O3@PI/PI nanocomposites containing 5 wt% BT@Al2O3reached 5.43. This work can be expected to provide an effective strategy to fabricate PI dielectric nanocomposite films for energy storage applications.

Effect of Temperature and Al2O3 NanoFiller on the Stress Field of CFRP/Al Adhesively Bonded Single-Lap Joints

In this paper, the effect of aluminum oxide, Al2O3, nanoparticles’ inclusion into Epocast 50-Al/946 epoxy adhesive at different temperatures, subjected to quasi-static tensile loading, is numerically investigated. The single-lap adhesive joint with two different types of material adherends (composite fiber-reinforced polymer (CFRP) and aluminum (Al) 5083 adherends) and adhesive Epocast 50-A1/hardener 946 were modeled in ABAQUS/CAE. A numerical methodology was proposed to analyze the effect on peel stress and shear stress by adding Al2O3 nanoparticles into the neat adhesive at 25 °C, 50 °C, and 75 °C temperatures at four different locations of the adhesive regions: the interface of the adhesive and aluminum adherend (location A), the middle plane of the adhesive region (location B), the middle longer edge (along the length of the adhesive, location C), and the middle shorter edge (along the width of the adhesive, location D). The results showed that adding nanoparticles into the neat adhesive improves joint strength at room and elevated temperatures. High peel and shear stresses were recorded near both edges of the locations (A, B, C, and D). For location A, adding nanofillers into the adhesive resulted in the reduction in peak peel stress by 1.3% for 25 °C; however, it increased by 2.7% and 10.7% for 50 °C and 75 °C temperatures, respectively. Furthermore, the peak shear stress observed a considerable reduction of 19.6% for 25 °C, but it increased by 7.7% and 8.7% for 50 °C and 75 °C temperatures, respectively, for location A. The same trend was also observed for other locations (i.e., B, C, and D). This signified that adding aluminum oxide nanoparticles in the adhesive resulted in increased stiffness at higher temperatures and increased ductility of the joint, as compared to the joint with neat adhesives at room temperature. Moreover, it was observed that locations A and B were more vulnerable to damage initiation, as the peak of stresses lay near the edges, indicating that the crack initiation would take place close to the edges and propagate towards the center, leading to ultimate failure.

Iron-Sepiolite High-Performance Magnetorheological Polishing Fluid with Reduced Sedimentation.

A sedimentation-stable magnetorheological (MR) polishing slurry on the basis of ferrofluid, iron particles, Al2O3, and clay nanofiller in the form of sepiolite intended for MR polishing has been designed, prepared, and its polishing efficiency verified. Added clay substantially improved sedimentation stability of the slurry, decreasing its sedimentation rate to a quarter of its original value (1.8 to 0.45 mg s−1) while otherwise maintaining its good abrasive properties. The magnetisation curve measurement proved that designed slurry is soft magnetic material with no hysteresis, and its further suitability for MR polishing was confirmed by its magnetorheology namely in the quadratically increased yield stress due to the effect of applied magnetic field (0 to 600 kA m−1). The efficiency of the MR polishing process was tested on the flat samples of injection-moulded polyamide and verified by surface roughness/3D texture measurement. The resulting new composition of the MR polishing slurry exhibits a long-term stable system with a wide application window in the MR polishing process.

Molecular Dynamics Simulations of Al2O3/Epoxy Nano-composite with Improved Heat-Resistance and Elastic Modulus

Thermal and mechanical properties of Al2O3/epoxy nano-composite, composed of bisphenol A diglygde ether (DGEBA) as matrix and 3,3-diaminodiphenyl sulfone (DDS) as curing agent filled with Al2O3 nanoparticles in sphere, cubic or tetrahedron shapes, are investigated through molecular dynamics simulations. Constant temperature constant pressure (NPT) ensembles and annealing cycles are utilized for modeling thermodynamic equilibrium systems in a wide temperature range. It is verified that all the three shaped Al2O3 nano-fillers can effectively improve heat-resistant and mechanical performances of epoxy polymer, in which sphere Al2O3 nano-fillers are the most significant in promoting mechanical stiffness and render an elevated glass transition temperature by 13.5 K. All three different shaped Al2O3 nano-fillers are capable of efficiently reduce thermal expansion coefficient and fractional free volume(FFV), accounting for the evident improvement in heat resistance, in which sphere and cubic Al2O3 nano-fillers are more preferential for decreasing thermal expansion coefficient by 13.92% and 12.66% respectively. Al2O3/epoxy nano-composite represents a substantial amelioration in elastic modulus, which is especially significant in the temperature range around glass transition temperature.

Xylem-Inspired Hydrous Manganese Dioxide/Aluminum Oxide/Polyethersulfone Mixed Matrix Membrane for Oily Wastewater Treatment.

Ultrafiltration membrane has been widely used for oily wastewater treatment application attributed to its cost-efficiency, ease of operation, and high separation performance. To achieve high membrane flux, the pores of the membrane need to be wetted, which can be attained by using hydrophilic membrane. Nevertheless, conventional hydrophilic membrane suffered from inhomogeneous dispersion of nanofillers, causing a bottleneck in the membrane flux performance. This called for the need to enhance the dispersion of nanofillers within the polymeric matrix. In this work, in-house-fabricated hydrous manganese dioxide–aluminum oxide (HMO-Al2O3) was added into polyethersulfone (PES) dope solution to enhance the membrane flux through a xylem-inspired water transport mechanism on capillary action aided by cohesion force. Binary fillers HMO-Al2O3 loading was optimized at 0.5:0.5 in achieving 169 nm membrane mean pore size. Membrane morphology confirmed the formation of macro-void in membrane structure, and this was probably caused by the hydrophilic nanofiller interfacial stress released in PES matrix during the phase inversion process. The superhydrophilic properties of PES 3 in achieving 0° water contact angle was supported by the energy-dispersive X-ray analysis, where it achieved high O element, Mn element, and Al elements of 39.68%, 0.94%, and 5.35%, respectively, indicating that the nanofillers were more homogeneously dispersed in PES matrix. The superhydrophilic property of PES 3 was further supported by high pure water flux at 245.95 L/m2.h.bar, which was 3428.70% higher than the pristine PES membrane, 197.1% higher than PES 1 incorporated with HMO nanofiller, and 854.00% higher than PES 5 incorporated with Al2O3 nanofillers. Moreover, the excellent membrane separation performance of PES 3 was achieved without compromising the oil rejection capability (98.27% rejection) with 12 g/L (12,000 ppm) oily wastewater.

Study of the Effect of Modified Aluminum Oxide Nanofibers on the Properties of PLA-Based Films.

To find out whether Al2O3 nanofiller is effective in improving the characteristics of polymer composites, composite polymer films based on biodegradable polylactide and epoxidized aluminum oxide nanofibers were obtained by solution casting. Surface morphology, mechanical and thermal properties of composites were studied by SEM, IR-Fourier spectroscopy, DSC and DMA. It was shown that, below and above the percolation threshold, the properties of the films differ significantly. The inclusion of alumina nanoparticles up to 0.2% leads to a plasticizing effect, a decrease in the crystallization temperature and the melting enthalpy and an increase in the tensile stress. An increase in the content of alumina nanoparticles in films above the percolation threshold (0.5%) leads to a decrease in the crystallinity of the films, an increase in stiffness and a drop in elasticity. Finding the percolation threshold of alumina nanoparticles in PLA films makes it possible to control their properties and create materials for various applications. The results of this study may have major significance for the commercial use of aluminum oxide nanofibers and can broaden the research field of composites.

Enhancing surface insulation of epoxy composite by constructing nanofiller‐skeleton charge channel

AbstractWith the increase of voltage level, the surface flashover of epoxy composite insulation material becomes an important issue, which restricts the development of UHV (Ultra High Voltage) transmission technology. In this article, a method of using SiC skeleton to construct charge channel was proposed, which can enhance the surface insulation performance of epoxy composite. In addition, we investigated the influence of SiC skeleton structure on charge dissipation and flashover voltage. At the same time, we explored the synergistic influence mechanism of SiC and Al2O3 nanofillers and SiC skeleton on the surface flashover characteristics of epoxy resin. The results showed that the SiC skeleton effectively enhances the surface insulation performance of epoxy resin. When Al2O3 nanofiller and SiC skeleton act simultaneously, the flashover voltage enhancement reached 13.65%. Combining with finite element simulation, the flashover voltage enhancement mechanism of epoxy resin after modified by nanofiller‐skeleton method was analyzed. It showed that the internal charge channel formed by the SiC skeleton plays an important role in suppressing the local field distortion. The results of the study provided a new idea for modifying epoxy composite to improve the flashover voltage.

Energy absorption performance of Kevlar/snake grass fiber composites under ballistic impact test with nano Al2O3 inclusion

AbstractPresent research work aims to know the significance of nanofiller aluminum oxide (Al2O3) loading on viscoelastic behavior and ballistic impact behavior of Kevlar/snake grass fiber (SGF) hybrid epoxy composites. A mechanical stirring process was used to modify the epoxy matrix by adding different weights (0%, 2%, 4%, 6%, 8%, and 10%) of the nanofiller Al2O3. The manual lay‐up method by subsequent hot pressing was used to create the Al2O3‐added Kevlar/SGF hybrid epoxy composites. The tensile, interlaminar shear, flexural, and impact strength were tested. When compared to the control sample, the 2 wt% filler‐loaded hybrid composites had higher tensile strength, flexural strength, impact strength, and interlaminar shear strength by 6.42%, 6.11%, 53.11%, and 11.08%, respectively. Furthermore, morphological analysis was performed on the mechanically tested samples to forecast the failure mechanism. The 2 wt% filler‐loaded hybrid epoxy composites demonstrated effective interfacial bonding with matrix and minimal fiber pullout, according to micrograph images. The developed hybrid composites were subjected to dynamic mechanical analysis (DMA). The DMA results demonstrated that hybrid composites with 8 wt% filler had better viscoelastic behavior than the control sample. Under a ballistic impact test, the ability of the Kevlar/SGF composites with nano Al2O3 inclusion to absorb energy was assessed. According to the findings, incorporating nano Al2O3 into Kevlar/SGF composites strengthened their ballistic impact resistance and energy absorption. The addition of 8 wt% nanofiller resulted in high energy absorption, according to ballistic impact studies. As compared to the control sample, the composite sample with 8% filler reveals a 68.80% enhanced energy absorption. Furthermore, the composite samples with the optimal wt% Al2O3 nanofiller can be used to mold impact‐resistant materials for a bulletproof vest.

Effect of Al2O3 and MgO nanofiller on the mechanical behaviour of alkaline-treated jute fibre–reinforced epoxy bio-nanocomposite

Effect of Al2O3 and MgO nanofiller on the mechanical behaviour of alkaline-treated jute fibre–reinforced epoxy bio-nanocomposite