Al2O3 Filler Research Articles

Polymer-Rich Composite Electrolytes for All-Solid-State Li-S Cells.

Polymer-rich composite electrolytes with lithium bis(fluorosulfonyl)imide/poly(ethylene oxide) (LiFSI/PEO) containing either Li-ion conducting glass ceramic (LICGC) or inorganic Al2O3 fillers are investigated in all-solid-state Li-S cells. In the presence of the fillers, the ionic conductivity of the composite polymer electrolytes (CPEs) does not increase compared to the plain LiFSI/PEO electrolyte at various tested temperatures. The CPE with Al2O3 fillers improves the stability of the Li/electrolyte interface, while the Li-S cell with a LICGC-based CPE delivers high sulfur utilization of 1111 mAh g-1 and areal capacity of 1.14 mAh cm-2. In particular, the cell performance gets further enhanced when combining these two CPEs (Li | Al2O3-CPE/LICGC-CPE | S), reaching a capacity of 518 mAh g-1 and 0.53 mAh cm-2 with Coulombic efficiency higher than 99% at the end of 50 cycles at 70 °C. This study shows that the CPEs can be promising electrolyte candidates to develop safe and high-performance all-solid-state Li-S batteries.

Izod impact performance of hybrid carbon nanotube-alumina filled epoxy nanocomposites

In this paper, multi-walled carbon nanotube (CNT) was hybridized with alumina (Al2O3) particles via chemical vapour deposition using nickel as a metal catalyst. The purpose of hybridization between CNT and Al2O3 particles is to prevent the agglomeration of the CNT due to van der Walls forces as well as to improve the impact performance of the epoxy nanocomposites. The Al2O3 particles work as “transport” for the CNT to homogenously disperse within the epoxy matrix. As a comparative study, the CNT-Al2O3 was also prepared through a physical mixing method. The assessment showed that the CNT–Al2O3 hybrid filler produced more homogeneous dispersion in the epoxy matrix with a higher Izod impact strength than the physically mixed CNT–Al2O3 filler. The izod impact strength of epoxy nanocomposites at 5 % wt of CNT–Al2O3 hybrid has increased up to 32 % compared to the neat epoxy.

Structural and vibrational studies on composites polymer electrolytes (PEO)10CF3COONa + x wt.% Al2O3

Composites formed by combinations of polyethylene oxide (PEO) and sodium trifluoroacetate (CF3COONa) with different aluminum oxide (Al2O3) concentrations were synthetized. Infrared (IR), Raman spectroscopy, X ray diffraction (XRD) and atomic force microscopy (AFM) analyses, were performed to characterize the composites. Changes on the XRD intensity peaks, and variations in intensity and position of some peaks in Raman and IR spectroscopy were observed for different concentrations of added Al2O3. The decrease in the XRD peaks of the PEO when it is combined with the salt, revealed that crystallinity in polymer was reduced, being lower when the alumina is added. The increase in roughness root medium square (RRMS) observed by AFM when Al2O3 was added, agree with reduction in crystallinity observed with XRD studies. Changes in the structure of PEO showed in the absorption lines IR and Raman, due to addition of CF3COONa salt and Al2O3 filler, have been attributed to the interactions between the electrolyte and the filler.

3D Printable Ceramic–Polymer Electrolytes for Flexible High‐Performance Li‐Ion Batteries with Enhanced Thermal Stability

This study establishes an approach to 3D print Li‐ion battery electrolytes with controlled porosity using a dry phase inversion method. This ink formulation utilizes poly(vinyldene fluoride) in a mixture of N‐methyl‐2‐pyrrolidone (good solvent) and glycerol (weak nonsolvent) to generate porosity during a simple drying step. When a nanosized Al2O3 filler is included in the ink, uniform sub‐micrometer pore formation is attained. In other words, no additional processing steps such as coagulation baths, stretching, or etching are required for full functionality of the electrolyte, which makes it a viable candidate to enable completely additively manufactured Li‐ion batteries. Compared to commercial polyolefin separators, these electrolytes demonstrate comparable high rate electrochemical performance (e.g., 5 C), but possess better wetting characteristics and enhanced thermal stability. Additionally, this dry phase inversion method can be extended to printable composite electrodes, yielding enhanced flexibility and electrochemical performance over electrodes prepared with only good solvent. Finally, sequentially printing this electrolyte ink over a composite electrode via a direct write extrusion technique has been demonstrated while maintaining expected functionality in both layers. These ink formulations are an enabling step toward completely printed batteries and can allow direct integration of a flexible power source in restricted device areas or on nonplanar surfaces.

Effect of Moisture Absorption on the Mechanical Properties of Ceramic Filled Jute/Epoxy Hybrid Composites

The present work emphasizes on the mechanical properties such as micro-hardness, flexural and impact strength of jute fiber and Al2O3 filler based polymer composites at dry and wet conditions. Composite samples reinforced with different wt.% of fibers and filler were prepared by hand lay-up technique. To improve the mechanical properties, jute fiber was hybridized with Al2O3 filler. The maximum flexural strength of 72.94 MPa and impact strength of 1.902 J is obtained for composites with 30 wt.% fiber content and 10 wt.% of filler content. The hardness of composite increases with increase in fiber and filler loading i.e 40 wt.% fiber content and 10 wt.% of filler content. The maximum hardness value is obtained 29.9 Hv. The effect of water absorption on mechanical properties of jute reinforced hybrid polymer composites is also investigated. To determine the influence of water absorption on the mechanical properties, specimens were immersed in distilled water for 10 days before testing. For reference purpose, dry specimens were tested. It is observed that the rate of water absorption depends on the fiber content as well as filler content. All the mechanical properties of composites are decreased after water absorption. Scanning electron microscopy (SEM) is used to characterise the microstructure and failure mechanisms of dry and wet jute fiber reinforced polymer composites.

Inter Laminar Shear Strength (ILSS) of Nano Al2O3 Filled Glass Fiber Reinforced Polymer (GFRP) Composite - A Study on Loading Rate Sensitivity

The objective of the research article is to study the loading rate sensitivity on ILSS of nano Al2O3 filled GFRP composite. Nano Al2O3 filler is impinged into the epoxy matrix at different volume fraction (Vf) of glass fiber. The GFRP composite is fabricated by hand- lay-up techniques. Inter laminar shear strength (ILSS) has been investigated at different loading rate or cross head velocity of 1, 50, 100, 500 and 1000mm/min. The results indicate that ILSS increases when loading rate increase from 1 to 100 mm/min and decreases further with increase in loading rate. This may be because of micro crack does not have sufficient time to propagate the weakest path and rather it has to propagate through the strong covalent bond between the matrix and nano particle or need to break the fiber for crack propagation for which ILSS increases. Experimental results showed that nano Al2O3 filler does not have any effect on glass transition temperature (Tg). Scanning electron microscope is used for fracture surface analysis to study the mode of fracture at different loading rate and correlate them with the ILSS results.

Tribological Properties of Organic Functionalized ZrB2–Al2O3/Epoxy Composites

The tribological behaviors of epoxy composites filled with organic functionalized ZrB2–Al2O3 were environmentally investigated and compared with those with as-received fillers under both dry and oil sliding conditions in this work. The worn surfaces and the transfer films on the counterparts were characterized by scanning electronic microscope (SEM), and the frictional temperature rising was investigated by infrared thermometer. The results demonstrated that the coefficient of friction (CoF), the wear rate, as well as the frictional temperature rise of the epoxy composites were all decreased due to the introduction of ZrB2–Al2O3 fillers. And with the increase in filler content, similar variation tendencies of CoF and wear rate of epoxy composites were observed under the different sliding conditions. Besides, the organic functionalization of ZrB2–Al2O3 fillers, which made the epoxy composites exhibit lower CoF and wear rate than those with as-received fillers, lowered the frictional temperature as well. In comparison, the epoxy composites filled with 5 vol% modified fillers presented better tribological properties, suggesting a stronger interfacial bonding between modified fillers and epoxy matrix. The dominant wear mechanisms of filled composites under dry and oil sliding conditions could be inferred as the combination of adhesive wear and abrasive wear and the fatigue wear, respectively, on the basis of SEM images of worn surfaces.

Evaluation of mechanical properties of Al2O3 and TiO2 nano filled enhanced glass fiber reinforced polymer composites

ABSTRACTThe present investigation has emphasized the implication of nano fillers (Al2O3 and TiO2) combined additions in glass fiber reinforced polymer composite on the variation of interlaminar shear strength (ILSS). The experiment has also investigated the effect of crosshead speed during testing and subsequent fracture surface analysis to find out the possible failure modes by scanning electron micrograph examinations. Loss and storage modulus have been experimentally evaluated to support the new findings in the present experimental design. It has been observed that the concurrent presence of nano Al2O3 and TiO2 fillers improves the ILSS. Dynamic mechanical thermal analysis indicated that, the addition of nano fillers reduces the storage and loss modulus of the composites. However, glass transition temperature has not been altered by the nano fillers addition. Box–Behnken design of experiment of surface response methodology has been adopted to optimize the filler content and crosshead speed. A second order mathematical model has been developed and the predicted optimum input parameters are 0.3 wt % Al2O3, 0.15 wt %TiO2, and 500 mm/min crosshead speed. Furthermore, the model predicted results are compared with experimental one and found a close agreement between them. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44274.

Effect of nano Al2O3 fillers and cross head velocity on interlaminar shear strength of glass fiber reinforced polymer composite

The present investigation emphasizes on the effect of nano Al2O3 filler and cross head velocity on mechanical properties of glass fiber reinforced polymer composite (GFRP). Nano Al2O3 filler of 3 wt% of epoxy is dispersed into the epoxy matrix through temperature assisted magnetic stirring followed by sonication for a time period of 60 min. GFRP composites are fabricated by hand-lay-up techniques. It is observed that flexural strength about 14 % and interlaminar shear strength (ILSS) about 11 % improved in nano Al2O3 filled GFRP composite as compared to control GF composites. Further, ILSS is evaluated as a function of volume fraction of glass fiber and at different cross head velocity (1, 50, 100, 500 and 1000 mm/min). The results revealed that ILSS values increases with cross head velocity from 1 to 100 mm/min and decreases further increase in cross head velocity. This may be attributed to at higher cross head velocity (up to 100 mm/min), micro cracks propagate through fiber/matrix interface rather than the weakest epoxy matrix and breaks the strong fiber during crack propagation resulting increase in ILSS. Addition of 3 wt% of nano Al2O3 does not have influences on glass transition temperature. Scanning electron microscopy images of ILSS fractured surface features are analysed to understand the failure mode of glass fiber reinforced polymer nano composites.

Ionic liquid-based sodium ion-conducting composite gel polymer electrolytes: effect of active and passive fillers

We report the studies on composite gel polymer electrolytes (GPEs) comprising 0.5 M solution of sodium trifluoromethane sulfonate (Na-triflate or NaTf) in ionic liquid 1-ethyl 3-methyl imidazolium trifluoromethane sulfonate (EMITf) entrapped in poly (vinylidinefluoride-co-hexafluoropropylene) (PVdF-HFP) dispersed with passive filler Al2O3 and active filler NaAlO2 particles. The free-standing films of the composite GPEs, prepared from solution-cast method, offer optimum ionic conductivity at room temperature (6.3–6.8 × 10−3 S cm−1 and 5.5–6.5 × 10−3 S cm−1 for Al2O3- and NaAlO2-dispersed GPEs, respectively), with sufficient electrochemical stability and excellent thermal stability up to 340 °C. As observed from XRD and SEM, the composites are of predominantly amorphous and porous character, which support the high ionic conduction. The sodium ion transport number has been found to be ∼0.27 for Al2O3-dispersed GPE and 0.42 for NaAlO2-dispersed GPE, which indicates the predominant role of passive and active fillers, Al2O3 and NaAlO2, respectively. The dispersion of NaAlO2 enhances the sodium ion conductivity in composite GPE substantially. The overall ionic conductivity is same as in the case of Al2O3 dispersion. The performance characteristics of GPE, particularly, dispersed with active filler NaAlO2 show its potential applicability as electrolyte/separator in sodium batteries.

Erosion wear behavior of coir fiber-reinforced epoxy composites filled with Al2O3 filler

Now-a-days, natural fibers have been receiving considerable attention as the substitute for synthetic fiber reinforcement in plastics. Among various fibers, coir is the most widely used natural fiber due to its advantages like easy availability, low cost, low density, low production cost and satisfactory mechanical properties. Fiber-reinforced polymer composites often have to function in severe erosive environment in which they encounter solid particle erosion. To this end, an attempt has been made in this paper not only to study the utilization potential of coir fiber in polymer composites, but also to study the effect of various parameters on erosion wear performance of coir fiber-reinforced epoxy composites filled with Al2O3 filler. Twenty different composite samples were prepared with different length (3 mm, 6 mm, 9 mm, 12 mm, and 15 mm) and content (5 wt%, 10 wt%, 15 wt% and 20 wt%) of fiber using hand lay-up technique. The erosion wear of these composites has been evaluated at different impingement angles (30°, 45°, 60°, 75°, and 90°) and at different impact velocities (48 m/s, 70 m/s, 82 m/s, and 109 m/s). The effect of fiber length and content on the erosion wear behavior of composites is also analyzed. A comparison has been made between composites with and without Al2O3 filler. It has been observed that composites filled with Al2O3 filler show better wear resistance properties as compared to composites without filler. To characterize the morphology of eroded surfaces and the mode of material removal, the eroded specimens are observed under scanning electron microscope.

Evaluation of thermal conductivity and flexural strength properties of poly(methyl methacrylate) denture base material reinforced with different fillers

Statement of problemPoly(methyl methacrylate) (PMMA) is widely used in prosthodontics as a denture base material. However, it has several disadvantages, including low strength and low thermal conductivity. PurposeThe purpose of this in vitro study was to evaluate thermal conductivity and flexural strength after adding powdered Ag, TiO2, ZrO2, Al2O3, SiC, SiC-nano, Si3N4, and HA-nano in ratios of 10 wt% to PMMA. Material and methodsA total of 144 specimens were fabricated and divided into 18 groups. Specimens were left in water for 30 days. Thermal conductivity values were measured using a heat flowmeter, flexural strength was measured with a 3-point bend test, and specimens were investigated with environmental scanning electron microscopy. One-way ANOVA was used to compare means followed by using Duncan multiple range test (α=.05). ResultsThe thermal conductivity value of PMMA increased significantly after the addition of Si3N4, SiC, Al2O3, SiC-nano, TiO2, ZrO2, HA-nano, and Ag. Progressive increases in thermal conductivity were observed in Si3N4, SiC, and Al2O3 fillers. Flexural strength values of the control group were not significantly different from those of the SiC, Al2O3, or Ag group (P>.05). In the other groups, flexural strength values decreased significantly (P<.05). On the basis of electron microscopy, we observed that Si3N4, SiC, and Al2O3 powders had higher thermal conductivity values that are dissipated more homogeneously in PMMA. ConclusionsAlthough the addition of 10 wt% SiC, Al2O3, and Ag powder to PMMA significantly increased thermal conductivity, the flexural strength values of PMMA were not significantly changed.

Improved flexible, controlled dielectric constant material from recycled LDPE polymer composites

In this study, recycled low density polyethylene (RLDPE) is developed with the addition of aluminum oxide (Al2O3) to have new polymer composites. The following wt% were used of the filler (1, 4 and 6 wt%). Tensile properties, Hardness, scanning electron microscopy (SEM) thermo gravimetric analysis, differential scanning calorimetry and dielectric properties were studied for these composites. 4 wt% Al2O3/RLDPE composites showed the optimum values of 15.52, 180.8 and 59.72 MPa for the tensile strength, tensile modulus and hardness were reported. Increasing the filler % decreased the mechanical properties of the composites due to agglomeration and poor surface contact with the polymer matrix. This is confirmed by SEM studies. Al2O3 filler increased the melting and crystallization temperature of RLDPE. Furthermore, it showed that Al2O3 filler improved the thermal stability of RLDPE with increasing the % of filler. Relative permittivity, dielectric loss factor and AC electrical conductivity were increased with increasing the amount of the AL2O3. The relative permittivity reached a value of 4.9 at 1 kHz frequency, which is a good value for a flexible composite prepared from recycled material and it can be used in electrical devices and electronic packaging.

Influence of Al2O3 on the structure and electrochemical properties of PVAc / PMMA based blend composite polymer electrolytes

In the present study, PVAc and PMMA blend based nanocomposite polymer electrolytes (CPEs) had been prepared by using a different content of nanosized Aluminium Oxide (Al2O3) filler, in order to examine the filler addition effect on the structural and electrochemical properties. The complexed nanocomposite polymer electrolytes were obtained in the form of dimensionally stable and free standing films by using solution casting technique. The thermal stability of the CPEs was evaluated using TG/DTA. The electrochemical properties of CPEs were measured by the AC impedance method. From the ionic conductivity results, the CPE containing Al2O3 filler 4wt% showed the highest ionic conductivity (8.76x10-3Scm-1) with an excellent thermal stability at room temperature. The sample exhibits higher ionic conductivity has also been subjected to scanning electron microscopy in order to study the microstructure of the electrolyte system.

A Comparative Study on Dry Sliding Wear Characteristics of Al&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; and Bone Powder Filled Hybrid Composites

The aim of the research was to develop E-glass/jute fiber reinforced epoxy composites with an addition of Al2O3 and bone powder by using hand layup technique and to compare tribological properties of these composites under similar test conditions. The wear experiments were designed according to Taguchi’s (L27) orthogonal array with three control variables such as sliding velocity, filler content and normal load. The results indicated that the normal load for Al2O3 and filler content for bone powder emerged as the significant factors affecting specific wear rate of hybrid composites. An addition of 10 wt% of bone powder or Al2O3 into E-glass/jute fiber reinforced epoxy composites increased the wear resistance considerably, and natural waste bone powder can be used instead of ceramic filler Al2O3 in hybrid composites. After the analysis of control factors, an optimal factor setting has been suggested for specific wear rate and coefficient of friction. Further, the scanning electron microscopy (SEM) images for worn surfaces of hybrid composites were studied. Finally, a confirmation test was carried out to validate the results.

Effect of filler on the oxidation protective ability of MoSi2 coating for Mo substrate by halide activated pack cementation

To protect molybdenum against oxidation, MoSi2 coatings were prepared by halide activated pack cementation, and the effect of filler cases, Al2O3, SiO2 and SiC, on the microstructure and oxidation resistance of MoSi2 coating was studied. The deposited coatings using Al2O3 and SiO2 filler presented a double-layer microstructure of the outer MoSi2 and the inner Mo5Si3 layer. Whereas, the coating deposited in SiC-filler case displayed only one MoSi2 layer. Lower inert ability of SiC filler in the pack and the possible reaction with molybdenum are responsible for the mono-layer structure. The coating prepared with SiO2 filler presented rough morphologies and more residual SiO2 fillers embedded on the coating surface than the Al2O3 or SiC filler cases. Attributed to the residual embedded fillers, all three kinds of deposited coatings exhibited perfect anti-oxidation property at 773K and could effectively protect molybdenum substrate against pest oxidation. As for high temperature oxidation of 1473K in air, the coating corresponding to SiO2 filler displayed the best oxidation protective ability with only 0.05% mass change after 110h oxidation. The protective SiO2 layer formed on the surface of MoSi2 coating at high temperature is responsible for the good oxidation resistance of the coating.

Raman spectra and structure of (1 − x)RbNO3 + xAl2O3 systems

By Raman spectroscopy the structural dynamic properties of rubidium nitrate RbNO3 and its heterogeneous composites with nanosized powder of alumina Al2O3 are studied at different temperatures, phase states, and concentrations of Al2O3 nanopowder. At high concentrations (x ≥ 0.5) of the Al2O3 filler an additional component with a maximum at ν 1 c ∼ 1049 cm−1 is detected in the Raman spectrum of the heterogeneous system. It can be assigned to NO 3 − vibrations located in the near-surface region of Al2O3 nanoparticles. Furthermore, at high concentrations (x ≥ 0.5) of the Al2O3 filler spectral manifestations of phase transitions of crystalline rubidium nitrate RbNO3 disappear. This indicates a radical change in the microstructure of the heterogeneous system in comparison with the homogeneous one.

Improving flexural and dielectric properties of MWCNT/epoxy nanocomposites by introducing advanced hybrid filler system

In this study, the authors attempted to enhance the flexural and dielectric properties of epoxy resin using advanced carbon nanotube–alumina (CNT–Al2O3) hybrid filler system that was chemically synthesised via chemical vapor deposition (CVD). The hybrid CNT–Al2O3 filled epoxy composite was compared to the physically mixed CNT–Al2O3 filled epoxy composites. The assessment showed that the CNT–Al2O3 hybrid filler produced more homogeneous dispersion in the epoxy matrix with higher flexural and dielectric properties as compared to the physically mixed CNT–Al2O3 filler. The flexural strength, flexural modulus and dielectric constant of CNT–Al2O3 hybrid epoxy composites improved significantly up to 30%, 35% and 20%, respectively, compared to the neat epoxy.

Innovative method to avoid the reduction of silver ions to silver nanoparticles in silver ion conducting based polymer electrolytes

In this research work an innovative method is used to prevent the silver ion reduction in solid polymer electrolytes. The x-ray diffraction (XRD) results reveal the disruption of the crystalline nature of chitosan (CS) and formation of silver nanoparticles upon addition of silver triflate (AgTf) salt. The UV-vis measurement confirms the existence of silver nanoparticles via the broad surface plasmon resonance (SPR) peak. Upon the addition of Al2O3 nanoparticles the SPR peak intensity is greatly reduced. The amorphous domain of the CS:silver triflate (CS:AgTf) system increases with the addition of Al2O3 nanoparticles up to 4 wt.%. Deconvolution of the XRD results reveals that a larger crystallite size is obtained for higher Al2O3 concentrations and the peaks due to silver nanoparticles almost disappear. Scanning electron microscope (SEM) analyses show that Al2O3 nanoparticles are well dispersed at low concentrations and the leakage of chains of silver nanoparticles to the membrane surface almost disappear. The XRD, UV-vis, SEM and energy-dispersive x-ray (EDX) results strongly support that the reduction of silver ions to silver nanoparticles (Ag+ → Ag°) in the CS:silver triflate system is significantly avoided upon the addition of an Al2O3 filler.

Effect of Al2O3 Filler on Mechanical Behavior Acrylic Films

Effect of Al2O3 Filler on Mechanical Behavior Acrylic Films