Alumina Nanofillers Research Articles

Effect of Ageing on Erosion Behavior of Epoxy Filled with Alumina Nano Filler

Effect of Ageing on Erosion Behavior of Epoxy Filled with Alumina Nano Filler

DRY SLIDING WEAR BEHAVIOUR OF CARBON NANOTUBE/ALUMINA/EPOXY HYBRID NANOCOMPOSITES

In the field of materials science, polymer composites have been extensively used in various industries such as marine, automotive, aerospace, sports and other industries due to their good dimensional stability and excellent structural properties. In this present research investigation, epoxy served as the polymer material, while multi-walled carbon nanotubes (MWCNTs) and alumina nanofillers were employed for reinforcing the matrix through hybridization. The wear characteristics of the composite material were examined under dry sliding conditions, employing a pin-on-disc machine with a track diameter of 50 mm. The load on the specimen was varied between low (20 N), medium (40 N) and high (60 N), while the weight fraction of the hybrid nanofillers underwent variations in a range of 0.1–0.5 w/% with an increment of 0.1 w/%. The results showed that the reinforcement of hybrid nanofillers significantly reduces the wear phenomena of the composite material. Hybrid nanocomposites with (0.1, 0.2 and 0.3) w/% of MWCNTs-Al2O3 exhibit noteworthy advancements in the wear resistance. Particularly the 0.3 w/% MWCNTs-Al2O3 hybrid nanocomposite demonstrates exceptional wear resistance compared to pure epoxy. The incorporation of 0.3 w/% of MWCNTs-Al2O3 results in a significantly improved wear resistance, with enhancements of (83, 81 and 80) % observed during low (20 N), moderate (40 N) and high (60 N) loading conditions, respectively, compared to pure epoxy. Similarly, deformation, delamination and filler plugging were observed with medium and high load. The surface morphology of the worn specimens was assessed through the application of field emission scanning electron microscopy.

The curing kinetics and properties of self-healing and thermally conductive polymeric composites based on ethylene vinyl acetate copolymer filled with nano alumina

We have investigated a self-healing thermally conductive Ethylene-vinyl acetate (EVA) hot melt adhesive (NAEDS, which denotes the addition of nano-alumina and disulfide bonded EVA hot melt adhesives) that can be used to effectively solve adhesive layer separation problem in photovoltaic (PV) modules and the difficulty of recycling. More specifically, we used diallyl disulfide as a cross-linking agent for EVA and alumina nanofillers as a reinforcing phase. The nano alumina filler gave the EVA better thermal conductivity. We used FTIR, SEM, and DSC to characterize and analyze NAEDS properties. The disulfide bonds in NAEDS underwent a rearrangement reaction under ultraviolet light, resulting in the self-healing of the resin (self-healing efficiency of 78.8%). The added nano alumina not only reduced the resin curing activation energy, improving its curing performance but also enhanced its thermal conductivity, achieving a 2.61 W/(m*k) thermal conductivity coefficient. The overall NAEDS performance is improved.

Estimating the wear behavior of hdpe composites reinforced with nano alumina fillers using taguchi method

Estimating the wear behavior of hdpe composites reinforced with nano alumina fillers using taguchi method

Effect of Nanoalumina (Al2O3) Filler on the Properties of Poly(Methyl Methacrylate) (PMMA)/50% Epoxidized Natural Rubber (ENR 50) Electrolytes

Effect of Nanoalumina (Al2O3) Filler on the Properties of Poly(Methyl Methacrylate) (PMMA)/50% Epoxidized Natural Rubber (ENR 50) Electrolytes

Impact of Gamma-Irradiated SiR-Al2O3 Nanocomposites and Degradation Diagnosis Using LIBS Method

The present study elucidates the impact of gamma irradiation on the thermal properties of silicone rubber nanocomposite insulation. Contact angle measurements, water droplet-initiated corona discharge studies and laser-induced breakdown spectroscopy (LIBS) studies are combined to provide a better understanding of the materials dielectric and thermal properties subjected to different irradiation dosages. The results show that the contact angle and the water-droplet initiated corona inception voltage decrease with increasing nanofiller content and gamma irradiation dosage. Analysis of the dielectric properties of the material following gamma irradiation, shows that the Cole-Cole double relaxation model fits well with the permittivity measured at different temperatures for both virgin and gamma-irradiated specimens. The coefficient of thermal expansion, deduced from the measured dielectric parameters, decreases with the increase of alumina nanofiller content and with the dosage of gamma irradiation. LIBS studies indicate that the ablation depth of the virgin and gamma-irradiated specimens becomes smaller when the filler content is increased. The coefficient of thermal expansion correlates directly with the plasma temperature measured using LIBS spectra of the nanocomposite material for non-irradiated and irradiated specimens.

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.

ENHANCING THE MECHANICAL, THERMAL AND ELECTRICAL PROPERTIES OF ALUMINA-MWCNT HYBRID NANOFILLER REINFORCED EPOXY COMPOSITES

In this work, alumina and multi-wall carbon nanotube (MWCNT) hybrid nanofiller reinforcing pure epoxy at varying weight fractions of (0.1, 0.2, 0.3, 0.4 and 0.5) w/% is investigated to enhance the mechanical, electrical and thermal properties. The porosity, tensile strength, electrical and thermal conductivity of epoxy hybrid nanocomposites are studied after the effects of the alumina-MWCNT hybrid nanofillers. The interfacial adhesion and mechanical interlocking between the hybrid nanofillers and epoxy are greatly increased with the addition of alumina and MWCNTs, thus leading to an improvement in the mechanical properties. Additionally, a uniform distribution of hybrid nanofillers results in a larger increase in the thermal and electrical conductivity. The presence of voids in specimens is gradually decreased when the nanofiller content is increased up to 0.3 w/%. The alumina-MWCNT reinforcement significantly improves the tensile strength, by 88 %, compared with pure epoxy. Similarly, the electrical and thermal conductivity increase by 85 % and 64 %, respectively, when compared with low weight fractions of the hybrid nanofiller. Agglomeration during the fabrication of nanocomposites is manageable but it is inevitable. During the formation of chains and networks, the alumina-MWCNT reinforcement of pure epoxy greatly influences the thermal conductivity. This strategy provides a prospective new concept for the use of epoxy and its composites in structural and thermal engineering applications.

Alumina Nanofiller Functionality on Electrical and Ion Transport Properties of PEO-PVdF/KNO3/SN Nanocomposite Polymer Electrolytes

Alumina nanofiller of 20 nm size has been dispersed with different weight percentages in succinonitrile (SN) plasticized PEO/PVdF/KNO3/SN polymer electrolyte system, and the samples have been prepared by solution cast. The ionic conductivity, dielectric properties are studied using impedance spectroscopy from 1 Hz to 10 MHz at various temperatures. The dielectric response of the samples is examined through dielectric constant (ε'), dielectric loss (ε''), modulus (M' and M'') and relaxation time (τ). The thermal properties of composite polymer electrolytes dispersed with nano alumina are changed remarkably. The ionic conductivity of composite polymer electrolytes has been enhanced by one order of magnitude with the addition of nanofiller, and the maximum ionic conductivity (0.207 × 10−3 S cm−1) is noticed for 2 wt% of Al2O3. The rise in conductivity is attributed to an increase in dissociation of ions and creation of a large number of free conducting paths for ion movement by the addition of nano-sized Al2O3.

The Effect of MWCNT and GNP on the Flame Retardant Properties of Glass Fiber Reinforced Composites

Nanotechnology in engineering is intended for achieving newer materials with immensely improved electrical, thermal and mechanical properties. The effectiveness of different fillers (micro and nanoscale) on the flame retardant behaviour of glass fiber reinforced epoxy composites were studied using cone calorimetry. In the present investigation, the fabrication of epoxy composites with ECR glass fiber reinforcement using the pultrusion method was taken up. The effect of incorporation of micron-sized ATH, carbon nanofillers like multi-walled carbon nanotubes (MWCNT) and Graphene nanoplatelets (GNP) is investigated. With respect to flame retardant properties, the composites with the combination of alumina (ATH) and carbon nanofillers show better results as compared to composites with individual fillers. The results exhibit a good agreement with more compact chars formed on the surface of the charred polymer. However, the cone calorimetry results of glass fibre reinforced composite show no significant improvement with respect to heat release rate. Further, Flame parameters of the composites show minimal deterioration due to the incorporation of the ATH and carbon fillers. Studies on the morphology using FESEM are well correlated with the flame properties.

Understanding the Surface Condition of Silicone Rubber Nanocomposite Due to Corona Aging Using AFM Imaging and LIBS Spectroscopy

Silicone rubber insulators undergo degradation when they are exposed to corona discharges. The present study explores the surface degradation behavior of silicone rubber alumina nanocomposites due to corona aging using high-frequency ac voltage. The electric field distribution on the sample surface during corona aging is simulated using COMSOL. The change in silicone rubber functional group is studied using Fourier transform infrared (FTIR) spectroscopy analysis. The influence of corona aging time on the surface roughness recovery of silicone rubber nano alumina composites is studied using an atomic force microscopy (AFM). The elemental distribution behavior and change in the emission spectra persistence time are analyzed during recovery period of corona-aged silicone rubber nanocomposites using laser-induced breakdown spectroscopy (LIBS) technique. The addition of alumina nanofiller to the silicone rubber improves the resistance to aging due to corona discharge. Loss and recovery of hydrophobic property of silicone rubber due to corona aging were determined using static contact angle measurement. The results show a direct correlation between the contact angle and the surface roughness recovery characteristics. They indicate that the nanocomposite having a 5 wt% alumina content exhibits the highest resistance to corona discharge with least surface damage. Furthermore, fast recovery was observed in the first few hours after corona aging, and most samples eventually regained their properties after about 8 h of recovery time.

Investigation of thermophysical properties of synthesized SA and nano-alumina reinforced polyester composites

Synthesis and characterization of 4-[(E)-(5-bromo-2-hydroxybenzylidene) amino]-N-(4-methylpyrimidin-2-yl) benzenesulfonamide (SA) has been performed. Alumina (Al2O3) and SA reinforced polyester composites are synthesized, and characterization processes are carried out. SA formed has been characterized by Fourier transform infrared (FTIR) spektrofotometre and nuclear magnetic resonance (NMR) spectroscopy. The thermal decomposition behavior of the nanocomposites in a nitrogen environment under non-isothermal conditions from 298 to 973 K is investigated with proportional-integral-derivative (PID) system. Thermal conductivity, Shore D hardness, and thermal decomposition behaviors of the nanocomposites that are added with alumina filler and synthesized with SA reinforcement have been compared. Nano-alumina filler raises the thermal conductivity coefficient and Shore D hardness of the polyester composites. The addition of synthesized SA reduces both the thermal conductivity coefficient and Shore D hardness. The thermal conductivity coefficient has been measured at the lowest in the pure polyester (0.056 W/m·K), and highest in the nano-alumina reinforced composite (0.072 W/m·K). The lowest Shore D hardness (nearly 68) is determined in the synthesized SA reinforced composite. Also, the experimental study has been optimized with the help of response surface methodology (RSM), and the improved theoretical models have been evaluated by statistical analysis.

Modeling the effect of uniform and nonuniform dispersion of nanofillers on electrical tree propagation in polyethylene dielectric

A phase-field model is developed in this paper based on the similarity between mechanical fracture and dielectric breakdown. Electrical treeing is associated with the dielectric breakdown in solid dielectrics by the application of high voltages. Instead of explicitly tracing the propagation of conductive channel, this model initializes a continuous phase field to characterize the extent of damage. So far, limited research has been conducted for simulating the effect of nanofiller dispersion on electrical treeing. No study has modeled the effect of uniform and nonuniform dispersion of nanofillers with varying filler concentration on treeing. Since electrical treeing tends to decrease the breakdown strength of solid dielectrics therefore, nanofillers are widely used to distract the tree from a straight channel to distribute its energy in multiple paths. Diverting a straight treeing channel into multiple paths reduces the chances of its propagation from live to dead-end hence, improving the breakdown strength. The physical and chemical nature of nanofillers has a crucial impact on increasing the resistance to treeing. In this paper, phase-field model is developed and used to simulate electrical treeing in polyethylene for varying concentrations of alumina nanofiller using COMSOL Multiphysics. Tree inception time, tree-growth patterns, and corresponding changes in dielectric strength is studied for both dispersions. Electrical treeing under different concentrations of alumina nanofillers with uniform and nonuniform dispersion is investigated in polyethylene as a base material. It is observed that fillers with uniform dispersion increases the resistance to treeing and tree inception time. Highest resistance to treeing is observed by adding 1% nanoalumina uniformly in raw polyethylene. Moreover, in uniform dispersion the tree deflects into multiple branches earlier than nonuniform dispersion impeding the damage speed as well.

Enhancement of Barrier and Mechanical Performance of Steel Coated with Epoxy Filled with Micron and Nano Alumina Fillers

Steel is an essential part of our life as it is used in wide applications as food equipment and heavy construction. The polymeric coating prevents the deterioration of the properties of metals due to rust and corrosion. This study investigated a reinforced polymeric coating to steel for enhancing barrier and mechanical properties. A comparison between different configurations of double-layered polymeric coatings was attained. The results showed that a maximum enhancement of 16.7%, 18.9%, 32.6%, 8.5%, and 5.7% in tensile strength, tensile strain, toughness, flexural strength, and flexural strain, respectively were achieved with a coating of epoxy filled with 1wt% Al2O3 microparticles before 1wt% Al2O3 nanoparticles on both sides as compared with pure epoxy coating. Adding micro/nanoparticles to epoxy coating enhanced the barrier properties of the coated steel against salt solution and citric acid environment as compared to pure epoxy coated steel.

Thermal behaviour and Vickers indentation response of random discontinuous Carbon/Epoxy composites with Nano-Alumina fillers

The glass transition temperature (Tg) of any thermosetting polymer-based composites is one of the vital parameters which helps in stipulating its service temperature. In contrast, Vickers indentation has long been a typical approach for material characterisation because it provides a simple, affordable, non-destructive, and objective way of assessing fundamental qualities from tiny quantities of materials. This study quantifies the thermal behaviour of randomly oriented discontinuous carbon fiber (RODCF) reinforced epoxy composites embedded with aluminum oxide (Al2O3) by its glass transition temperature (Tg). Further, the hardness of the composite samples is measured using the technique of Vickers indentation. 10 per hundred resin (phr) RODCF in terms of weight was reinforced in epoxy with 0, 1 and 2 phr of Al2O3 respectively. Neat epoxy was also tested for reference. It was found that compared to neat epoxy, RODCF/epoxy possessed a higher value of Tg and Vickers Hardness (HV). Tg increased further with the addition of Al2O3. The HV change observed was insignificant at 1 phr Al2O3 incorporation, but a substantial increment was observed at 2 phr Al2O3 addition to the RODCF/epoxy.

Experimental investigation of Mode-I fracture behavior of nano alumina filler reinforced hybrid composites

Fracture mechanics is the field of mechanics deals with the propagation of cracks and failure study in materials. Understanding of fracture behaviour in hybrid polymer composites is challenging in the field of structural applications. In this study Mode-I fracture behavior was investigated on glass-nylon-6 fiber hybrid composite with alumina nanofiller as the single edge notched bending specimen was used to perform the fracture toughness test as per ASTM 5045–99 standards. The fractured surfaces of the glass-nylon fiber reinforced hybrid polymer composite with alumina nanofiller under mode-I testing were observed by scanning electron microscope. Results showed that hybrid composites show remarkable fracture toughness increase up to 1% nanofiller addition with good adhesion between the matrix and filler phases.

Effect of Fibre Surface Treatment and Nanofiller Addition on the Mechanical Properties of Flax/PLA Fibre Reinforced Epoxy Hybrid Nanocomposite.

Natural fibre-based materials are gaining popularity in the composites industry, particularly for automotive structural and semi-structural applications, considering the growing interest and awareness towards sustainable product design. Surface treatment and nanofiller addition have become one of the most important aspects of improving natural fibre reinforced polymer composite performance. The novelty of this work is to examine the combined effect of fibre surface treatment with Alumina (Al2O3) and Magnesia (MgO) nanofillers on the mechanical (tensile, flexural, and impact) behaviour of biotex flax/PLA fibre reinforced epoxy hybrid nanocomposites. Al2O3 and MgO with a particle size of 50 nm were added in various weight proportions to the epoxy and flax/PLA fibre, and the composite laminates were formed using the vacuum bagging technique. The surface treatment of one set of fibres with a 5% NaOH solution was investigated for its effect on mechanical performance. The results indicate that the surface-treated reinforcement showed superior tensile, flexural, and impact properties compared to the untreated reinforcement. The addition of 3 wt. % nanofiller resulted in the best mechanical properties. SEM morphological images demonstrate various defects, including interfacial behaviour, fibre breakage, fibre pullout, voids, cracks, and agglomeration.

Influence of Nanofiller Dispersion on Electrical and Mechanical Properties of Epoxy Alumina Nanocomposites

The electrical and mechanical properties of the epoxy alumina nanocomposites depend on the uniform dispersion of the nanofiller in the epoxy matrix. Epoxy alumina nanocomposites were prepared using 1, 3, and 5 wt% of alumina nanofiller, and electrical and mechanical properties were analyzed using experimental and modelling studies. Water droplet initiated corona inception voltage (CIV) was identified using fluorescence fiber technique and by Ultra High Frequency (UHF) technique, under AC and DC voltages. The CIV formed due to water droplet have reduced drastically with increase in number of droplets and fluorescent fiber technique found to be more sensitive to identify water droplet initiated discharges. A micro mechanical model was proposed to analyse the combined effect of the interphase and agglomeration properties of the alumina nanoparticles on the tensile strength of epoxy alumina nanocomposites. Variation in ϕagg, Eagg, and E were analysed by adopting the non-parametric distribution of alumina nanoparticles and Young’s modulus increased with the increment in the alumina nanofiller dispersion level. The presence of aggregated particles exhibits a negative effect on the tensile properties of nanocomposites.

Investigation on Surface Condition of the Corona-Aged Silicone Rubber Nanocomposite Adopting Wavelet and LIBS Technique

Silicone rubber nanocomposites were prepared using 1, 3, 5, and 10 wt% of alumina nanofiller. Corona inception voltage (CIV) due to water droplets was measured using fluorescence technique, and it has decreased for alumina-added silicone rubber nanocomposites and with corona-aged samples. The effect of the corona discharges on the surface morphology characteristics of the nanocomposites was analyzed by measuring contact angle, surface profile measurement using atomic force microscopy (AFM), and characterized by adopting multiresolution signal decomposition (MRSD) technique. The addition of the alumina nanofiller suppressed the surface roughness for the corona-aged nanocomposites and 5-wt% sample observed to have the lowest surface roughness values. Recovery of the surface roughness caused by corona discharges was analyzed at different time intervals, and it was observed that alumina nanoparticle-added silicone rubber showed an incremental reduction in the roughness recovery rate. The laser-induced breakdown spectroscopy (LIBS) technique was adopted to analyze the nanocomposites after the corona aging, and further plasma temperature was evaluated at different recovery times. The addition of an alumina nanofiller increased the plasma temperature, and 5-wt% samples have the lowest plasma temperature recovery rate after corona aging. The analysis of the study indicates that the corona-aged silicone rubber specimen surface properties recover in 8 h of resting time period.

Leveraging trace nanofillers to engineer ultra-low wear polymer surfaces

Trace nanofillers have proven unable to stabilize polymer surfaces due to their inability to reinforce the subsurface. Thus far, their effects on surface wear have been obscured by potentially unrelated subsurface mechanics. In this paper, we addressed this problem by first eliminating matrix (PTFE) subsurface instability with a secondary filler (5 wt% PEEK) and then by stabilizing the sliding surface using variable loadings of trace alumina nanofillers. At the optimal loading of 0.1 wt%, the nanofillers reduced wear rates of an already low wear PEEK-PTFE blend by an unprecedented 50-fold. The minimum loading of 0.01 wt% reduced wear by 10-fold. Surface analysis revealed that trace nanofillers triggered ultra-low wear by catalyzing tribochemical changes that effectively crosslinked, anchored, and stabilized near-surface polymer chains. The degradation of wear performance at nanofiller loadings well above the 0.1 wt% optimum suggested that the mechanical detriments of greater loadings outweighed their tribochemical benefits. To our knowledge, this study is the first to isolate the effects of trace nanofillers on polymer surface stability and the first to demonstrate their radical wear-reducing potential. This hybrid approach – independently targeting surface and subsurface stability – serves as a roadmap for isolating the effects of other important nanofillers (e.g. CNT's) and engineering ultra-stable tribological surfaces.