Binary Nanofillers Research Articles

A novel approach to obtain superior microwave absorption using Non-Conducting polymer jacket coated Multi-Layer Hexaferrite-TMDC nanocomposite film

This article represents the imposing electromagnetic interference (EMI) shielding behaviour of non-conducting polymer jacket-coated Co2Y-hexaferrite-MoS2 binary nanofillers incorporated PVDF multi-layer nanocomposite films. The presence of Co2Y-hexaferrite inside PVDF enhanced the magnetic permeability, whereas the incorporation of semiconducting transition metal dichalcogenide (TMDC), MoS2, inside the PVDF matrix improves the polarization effects of the nanocomposite films. The crystalline phases corresponding to Co2Y-hexaferrite, MoS2 nanoparticles and the multi-phase nanocomposite films have been justified using XRD analysis and Rietveld refinement study. FESEM micrographs confirm the hexagonal and cotton-ball structures of Co2Y-hexaferrite and MoS2 nanoparticles, respectively; in addition, the presence of Co2Y-MoS2 binary nanofillers inside the PVDF matrix has been confirmed. The stability of the nanocomposite films against electrical breakdown is clearly demonstrated by the minimum leakage current observed at 90 kV/m under J-E characteristics. The room temperature maximum magnetization of 33.32 emu/g of Co2Y-hexaferrite at an external magnetic field of 50,000 Oe helps in incurring magnetic losses and the corresponding improvement of shielding effectiveness due to absorption (SEA) of the nanocomposite films. This article demonstrates the modulation of SEA of the nanocomposite films depending on both the binary nanofillers loading percentage inside PVDF and the thickness of the nanocomposite films. Also, a unique mechanism corresponding to the coating of a non-conducting polymer jacket over a multi-layer structure has been opted herein to improve SEA in the frequency range of 12–18 GHz. This unique mechanism demonstrates that the maximum SEA for the non-conducting polymer jacket-coated multi-layer nanocomposite film is −51.23 dB at 14.03 GHz, and the corresponding total shielding effectiveness (SET) is −74.51 dB at 13.23 GHz, along with > 99.9999 % attenuation.

An effective microwave absorber using multi-layer Design of carbon allotrope based Co2Z hexaferrite-Polymer nanocomposite film for EMI shielding applications

This report shows impressive electromagnetic interference (EMI) shielding efficiency of laminated nanocomposites of PVDF containing binary nanofillers of rGO and Co2Z hexaferrite. These rGO layers in the PVDF matrix in association with magnetic nanofillers have been considered to improve interfacial polarization by accumulating charges at the interfaces of rGO-Co2Z hexaferrite-PVDF system. The crystallographic phase, chemical composition, and successful incorporation of the binary nanofillers into PVDF have been verified using XRD, XPS, RAMAN, and FESEM analysis. The J-E analysis of rGO-Co2Z hexaferrite-PVDF nanocomposite films confirm that the current density of all the nanocomposite films is very less and found in the order of 10-5 A/m2 under the maximum electric field of 70 kV/m. This indicates the emergence of polarization effect in the nanocomposite films when subjected to high external electric field without having electrical breakdown. The significant magnetization of ∼8.9 emu/g for nanocomposite films, at room temperature is beneficial for boosting the EMI shielding effectiveness due to absorption (SEA). The combination of magnetization and electrical polarization in nanocomposite film helps to attain significantly high total shielding effectiveness (SET) in the frequency range of 12–18 GHz. The shielding effectiveness study of both mono-layer and multi-layer nanocomposite films have been investigated. Improvement of SEA has also been achieved by the elevation of the thickness of the nanocomposite film within the range of 0.8 to 1.0 mm, which in turn improves SET to a value of −54.09 dB at 15.70 GHz for multi-layer system of thickness 0.861 mm with >99.999 % of attenuation whereas the mono-layer film of thickness 0.180 mm shows the SET of −47.03 dB at 14.76 GHz with an attenuation of >99.99 %.

Enhancing comprehensive performance of epoxy-based sealing layer with a binary nanofiller for underground hydrogen energy storage

Underground hydrogen energy storage (UHES) placing higher demands on the mechanical property, thermal conductivity and gas barrier capacity of the sealing materials. In this study, binary nanofillers consisting of impermeable graphene oxide (GO) and highly thermally conductive aluminum oxide (AO) linked by 4,4′-diphenylmethane diisocyanate (MDI) are incorporated. Composite sealing layers with varying mass fractions (Mf) of binary nanofillers are prepared using in situ polymerization with epoxy (EP) as matrix. Results show that the ultimate displacement, thermal conductivity and gas barrier capacity of the composite sealing layers increased with increasing Mf of binary nanofillers. The optimized composite sealing layer with 10 % Mf of binary nanofillers demonstrated sult and λ values of 28.54 mm and 0.35 Wm−1 k−1, respectively, which represent a 32.77 % and 118.75 % increase compared to pure EP. Besides, the GTR is reduced to 122.57 cm3 m−2 d−1 atm−1, which is a 24.63 % decrease compared to pure EP.

Dynamic viscoelastic behavior and interlaminar performance of glass/epoxy composites with binary nano‐fillers at different in‐situ elevated temperature environments

AbstractFor commercial civil applications of laminated composite material, characterizations to forecast the interlaminar shear behavior and viscoelastic response across a wide temperature range are essential. In this study, the interlaminar shear strength (ILSS) of glass/epoxy (GE) composites dispersed with binary nanofillers nanosilica‐multilayer graphene (NS‐MLG) and nanosilica‐nanoclay (NS‐NC) was analyzed at an in‐situ testing temperature of 20, 70, and 110°C. Further, the viscoelastic property of the composites was studied using a dynamic mechanical thermal analyzer (DMTA) in the temperature range of 35–165°C. An increase in the ILSS value of around 9% and 10% was observed at room temperature for GE/MLG‐NS and GE/NC‐NS, respectively, compared to control GE composites. In contrast, the trend was seen to change at higher temperatures. There was a slight decrement in the storage modulus (E′) of GE/MLG‐NS and GE/NC‐NS composites in the glassy region compared to control GE composites. The mean Tg of the GE composite (control) was nearly 107.3°C when the E′ decline onset temperature was taken into account, but after the addition of MLG‐NS, it was 10.1°C below. The mean Tg of GE/NC‐NS was determined to be 106.3°C, and in the glass transition as well as rubbery regions, it was observed to compete with the E′ value of the control GE composites. Fractography was done using micrographs obtained from environmental scanning electron microscope (ESEM). Traces of polymeric material found at the fiber surface certified the improved interfacial adhesion between glass fiber and polymer in the matrix‐modified composite samples.

Mechanical Properties and Corrosion Behavior of Dual-Filler-Epoxy-Coated Steel Rebar under a Corrosive Environment

The deterioration of steel rebar in reinforced concrete is a major issue that reduces RC structures’ durability and structural integrity. Significant efforts have been devoted to developing high-performance coatings to provide efficient protection of the rebar, and one promising approach is to utilize nanofiller as additives to improve the performance of polymer resins. This study aimed to improve the corrosion resistance of steel rebar by applying an epoxy coating with graphene nanoplatelets (GNPs) and silica nanopowders (NSs) as additives. The corrosion behavior of nanocomposite-coated rebars was characterized via an electrochemical impedance spectroscopy (EIS) test, and salt spray exposure was utilized to evaluate the durability of the coated rebars. Investigation of abrasion resistance and mechanical properties of the coatings was conducted using the falling sand test and tensile coupon test. In addition, the nanocomposites were scanned by micro-CT to explore the effect of binary nanofillers on the intactness of the polymeric matrix. The GNP-NS hybrid filler reduced the void fraction to 0.002%, whereas the void fraction in pure epoxy was 0.07%. Significant reinforcement was found in the mechanical properties; the addition of GNP-NS hybrid filler increased the tensile strength to 37.1 MPa, a 56% increase compared to the pure epoxy. Additionally, the GNP-NS hybrid fillers have led to an improvement of 16% in the Young’s modulus. In terms of corrosion resistance, the Rc value of rebar coated with GNP-NS coating was about three times greater than the ones coated with a single-filler epoxy coating during the initial test, and this value remained undegraded after 200 hr of exposure. In contrast, the group containing hybrid fillers displayed the lowest thickness loss following abrasion testing, with a 74% reduction in thickness loss, showing the coating’s high abrasion resistance. Hence, the results reveal that GNP-NS hybrid fillers have superior wear resistance, mechanical capabilities, anticorrosion properties, and durability. This research provides valuable insights into developing and implementing high-performance polymeric material to protect steel rebars in concrete structures, therefore significantly increasing the sustainability of concrete structures.

Fabrication of hydrophobic and enhanced anticorrosion performance of epoxy coating through the synergy of functionalized graphene oxide and nano-silica binary fillers

Two-dimensional graphene oxide (GO) nanosheets have emerged as ideal nano-fillers in anticorrosive epoxy coatings, but their poor dispersion because of π-π interaction, high hydrophilicity, and low compatibility with epoxy resin limit their application. In this work, to conquer these obstacles, the hydrophobic and anticorrosive GO based epoxy composite coating was developed via the synergistic enhancement effect of binary nano-fillers. To achieve this goal, the graphene oxide and nano-silica (SiO2) were hydrophobically functionalized by the 1H,1H,2H,2H-perfluoro-decyl triethioxy silane (PFDS) via a simple grafting method (SiO2-P: mSiO2:mPFDS=1:1), GO-P3: mGO:mPFDS=1:3), which were applied as binary fillers to reinforce the epoxy coating with enhanced dispersion and compatibility with matrix. Benefiting from the hierarchical micro-/nano- structure, regulated surface energy, good dispersion, and synergy of SiO2-P and GO-P3 binary fillers, the epoxy composite coating showed greatly enhanced hydrophobicity (The water contact angle increased from 70.45° to 126.84°) and anti-corrosion performance. With the synergetic enforcement of 1.5 wt % SiO2-P and 0.5 wt % GO-P3, the prepared epoxy composite coating exhibited the best anticorrosive performance with impedance of 2.74 × 109 Ω·cm2 (0.01 Hz) after immersion in 3.5 % NaCl medium for 30 days, which was confirmed by the salt spray test results. Meanwhile, the anti-corrosion mechanism including hydrophobicity and prolonged diffusion path of water-soluble corrosive medium was tentatively discussed.

Morphologic and synergistic effects of GNP/NS binary-filler-based multifunctional coatings with robust anti-corrosion and hydrophobic properties

Traditional protective coatings used for metallic structures, such as oil/gas metallic pipelines and bridges, often suffered from premature damage due to either low corrosion resistance or weak mechanical performance. Thus, this study proposed a new nanocomposite coating that reinforced by binary nanofillers with graphene nanoplatelets (GNP) and nano-silica (NS) with multiple functionalities, striving for superior corrosion resistance and hydrophobic properties, as well as promising mechanical damage tolerances. A comprehensive experiment was conducted to characterize their mechanical, electrical, and tribological properties of the new developed nanocomposite coatings. The corrosion protection performance of the coatings was evaluated by electrochemical impedance spectroscopy (EIS) and long-term accelerated salt spray test. Tribological properties were evaluated using abrasion test. Test result demonstrated that the new composite with the combination of GNP with NS exhibited significantly improved corrosion protection performance, mechanical strength, and abrasion resistance. The GNP/NS hybrid filler nanocomposites remarkably enhanced the barrier and corrosion protection properties against environmental attack. Enhanced mechanical properties and wear resistance of the composite coatings allows high damage tolerance for engineering applications.

Fabrication of heterostructure composites of Ni-Zn-Cu-Ferrite-C3N4-Poly(vinylidene fluoride) films for the enhancement of electromagnetic interference shielding effectiveness

In this report the emphasis has been given on the influence of carbon nitride (C3N4) semiconducting fillers for the enhancement of the electromagnetic interference shielding effectiveness. This is the first ever report where the inexpensive composite nanomaterials of Ni-Zn-Cu-Ferrite-C3N4-Poly(vinylidene fluoride) are fabricated by very simple solution casting method. Structural and chemical studies have confirmed the presence of all the required phase of the component materials in the heterostructure composite films. The magnetic NZCF nanoparticles are responsible for the generation of the high magnetic loss in terms of domain wall resonance. Also, C3N4 semiconducting fillers all around the NZCF nanoparticles and the interactions between these binary nanofillers and the β-phase reach PVDF matrix are responsible for the generation of polarization loss, conduction loss and eddy current loss by their interactions with the electromagnetic (EM) wave of GHz frequency range. The presence of these binary nanofillers (Ni-Zn-Cu-Ferrite-C3N4) inside the matrix of PVDF are responsible for the improvement of the shielding effectiveness due to absorption and shielding effectiveness due to reflection. High value of total shielding effectiveness of −71.5 dB and −88 dB has been observed corresponding to the X-band and Ku-band for these NZCF-C3N4-PVDF composite films. Such high value of attenuation of >99.999999% and the corresponding wide bandwidth of NZCF-C3N4-PVDF composite films offers a completely new insights for the fabrication of microwave absorber to combat against electromagnetic pollution.

Electromagnetic Shielding Effectiveness of X-Type Hexaferrite-C3N4 Binary Nanofiller-Incorporated Poly(vinylidene fluoride) Multiphase Composites

The significant influence of magnetic X-type hexaferrite-C3N4 binary nanofillers on the shielding effectiveness of poly(vinylidene fluoride) heterostructure composite materials has been displayed in the present report. The overall improvement in shielding effectiveness of these multiphase composite structures is immensely important for the prevention of electromagnetic pollution in the GHz frequency range. The uniqueness of this magnetic-semiconducting binary composite system helps improve the shielding effectiveness due to absorption (SEA) and reflection (SER) as well as total shielding effectiveness (SET) of the X-type hexaferrite-C3N4-PVDF heterostructure composite materials. The high magnetic loss in terms of domain wall resonance together with the eddy current loss produced by these X-type hexaferrite-C3N4 binary composite nanofillers inside the polar structure of β-phase reaches the PVDF matrix and the dielectric loss of the composite materials helps improve SEA to a maximum value of approximately −62 dB at 13.95 GHz as well as SET to a maximum value of approximately −73 dB in the X-band and approximately −88 dB in the Ku-band of the resultant composite structures. The high attenuation (>99.999999%) of these X-type hexaferrite-C3N4-PVDF heterostructure composite materials makes them the most useful for the applications in the microwave/GHz frequency region.

Synergistic enhancement of arc ablation resistance and mechanical properties of epoxy resin insulation

Arc ablation is one of the important inducements leading to the surface insulation failure of epoxy resin (EP) break insulation in a HVDC circuit breaker. As a promising method to enhance the arc ablation resistance of EP insulation, the use of heat-conducting nano-fillers has always been confronted with the contradiction between the enhancement of thermal properties and that of mechanical strength. Up to now, the ablation characteristics of EP nanocomposite under short-time partial arc ablation is still poorly understood, and the synergistical enhancement of arc ablation resistance and mechanical strength of EP insulation is not realized as yet. Focused on these uncharted areas, in this work, we prepared a novel EP nanocomposite by blending method using dopamine-modified h-BN flakes and rigid α-Al 2 O 3 microsphere as binary modifiers. The results indicate that, though the arc ablation resistance of EP insulation can be improved to some extent after introducing functionalized h-BN, however, the tensile strength decreases significantly. In comparison, the h-BN&α-Al 2 O 3 binary nanofillers may not only improve the apparent activation energy of EP insulation in thermal decomposition, but also regulate the interfacial interaction between particle swarms and EP matrix. This is beneficial to relieve the partial carbonization on the insulation surface thereby improving the toughness of the composite, which provides a feasible method to synergistically enhance the multiple properties of EP insulation.

Synergistic Effects of Boron Nitride (BN) Nanosheets and Silver (Ag) Nanoparticles on Thermal Conductivity and Electrical Properties of Epoxy Nanocomposites.

Polymer composites, with both high thermal conductivity and high electrical insulation strength, are desirable for power equipment and electronic devices, to sustain increasingly high power density and heat flux. However, conventional methods to synthesize polymer composites with high thermal conductivity often degrade their insulation strength, or cause a significant increase in dielectric properties. In this work, we demonstrate epoxy nanocomposites embedded with silver nanoparticles (AgNPs), and modified boron nitride nanosheets (BNNSs), which have high thermal conductivity, high insulation strength, low permittivity, and low dielectric loss. Compared with neat epoxy, the composite with 25 vol% of binary nanofillers has a significant enhancement (~10x) in thermal conductivity, which is twice of that filled with BNNSs only (~5x), owing to the continuous heat transfer path among BNNSs enabled by AgNPs. An increase in the breakdown voltage is observed, which is attributed to BNNSs-restricted formation of AgNPs conducting channels that result in a lengthening of the breakdown path. Moreover, the effects of nanofillers on dielectric properties, and thermal simulated current of nanocomposites, are discussed.

A study of the effect of carbon nanotube/nanoclay binary nanoparticle reinforcement on glass fibre/epoxy composites

Fiber reinforced polymer composite materials are being used as a potential replacement to metals in a number of applications because of their light weight and superior strength properties. Though FRP composites have found utility in a variety of fields, couple of limitations exists which compels the researchers to find alternative ways to improve the properties even further. One such way is the use of nanofillers like CNT and nanoclay. Different nanofillers have different interactions as a result they affect several properties of composites in various forms. This study aims at investigating the effect of incorporating binary nanoparticles and the variation of composition of nanoclay on mechanical properties of carbon nanotube/nanoclay binary particle reinforced glass fibre/epoxy composite laminates. Composite laminates with different composition with respect to nanoclay has been fabricated i.e. 0.1 CNT- 0.1 NC-GE, 0.1 CNT-0.5 NC-GE, 0.1 CNT-1 NC-GE and their mechanical properties are evaluated. They are further compared to neat GE, 0.1 CNT-GE and 0.5 NC-GE composite samples. Flexural testing showed that variation of composition of nanoclay resulted in a wide variation in properties. 0.1 CNT-0.5 NC-GE showed maximum increase in flexural property with ∼17.9% increase in the flexural strength as well as ∼12.3% increase in the flexural modulus in comparison to neat GE composite. 0.1 CNT-0.1 NC-GE and 0.1 CNT-1 NC-GE did not show appreciable improvement in flexural properties. Upon fracture, fractography study has been done to establish the primary failure mode, extent of bonding and the effect of binary nanofillers on the fracture mechanism using FESEM.

Carbon nanotubes-bridged-fumed silica as an effective binary nanofillers for reinforcement of silicone elastomers

The incorporation of nanofillers into polymeric matrix has been proven to be an effective route to reinforce their mechanical properties, and the usage of binary fillers that combines the advantages of the two fillers could lead to further property enhancement. In this work, binary nanofillers consist of multi-walled carbon nanotubes (MWCNTs)-bridged fumed silica (FSiO2) were synthesized for the first time by Pt coupling reaction of methyldiethoxysilane (MDES) modified MWCNTs and triethoxyvinylsilane (TEVS) functionized SiO2, in which MDES modified MWCNTs was synthesized by reacting OH-functionized MWCNTs with MDES, while TEVS-FSiO2 was obtained by reacting fume silica with TEVS. The binary MWCNTs-bridged-FSiO2 was introduced into liquid silicone rubber (LSR) for mechanical reinforcement. It is shown that the interfacial interaction between binary fillers and LSR matrix is significantly enhanced due to the chemical bridging as well as the excess TEVS molecules on SiO2, and the Young's modulus, tensile strength and tear strength of the LSR could be increased by 64%, 29% and 52%, respectively, with incorporation of only 0.25 phr of MWCNTs for the binary fillers. The observed mechanical enhancement could be attributed to good interfacial interaction between the fillers and LSR due to the existence of SiO2 (with excess matrix compatible molecules) on the surface of MWCNTs, which facilitate the filler dispersion in LSR matrix and the promote stress transfer from matrix to MWCNTs, as well as the advantages of extremely high aspect ratio and excellent mechanical strength of MWCNTs.

Clay-Facilitated Aqueous Dispersion of Graphite and Poly(vinyl alcohol) Aerogels Filled with Binary Nanofillers.

Dispersion of graphite in water was achieved using clay as dispersing aid. In the absence of polymer, the clay/graphite suspensions were sufficiently stable to produce aerogels composed of very thin layers of uniformly dispersed nanoparticles. Poly(vinyl alcohol) (PVOH) aerogels containing binary nanofillers (clay plus graphite) were then fabricated and tested. These composites were found to maintain low thermal and electrical conductivities even with high loading of graphite. A unique compressive stress-strain behavior was observed for the aerogel, exhibiting a plateau in the densification region, likely due to sliding between clay and graphite layers within the PVOH matrix. The aerogels containing only graphite exhibited higher compressive modulus, yield stress and toughness values than the samples filled with binary nanofillers. X-ray diffraction (XRD) spectra for the same composite aerogel before and after compression testing illustrated the compression-induced dispersion changes of nanofillers. Composites containing 50 wt % graphite demonstrated a downshift of its 2D Raman peak implying graphite exfoliation to graphene with less than 5 layers.

Cellulose Nanofibers-Graphene Nanoplatelets Hybrids Nanofillers as High-Performance Multifunctional Reinforcements in Epoxy Composites

The objective of this study was to fabricate epoxy polymer composites modified with cellulose nanofibers (CNFs) and graphene nanoplatelets (GNPs) binary filler materials. Individual (0.2 wt.% GNPs or 2 wt.% CNFs) and binary nanofillers (mixture of 0.5 wt.% CNFs and 0.1% GNPs) were incorporated into an epoxy matrix system to investigate the synergistic effect of nanofillers on composites properties. Dynamic mechanical analysis (DMA) and three point bend tests were carried out to investigate the viscoelastic and flexural properties of neat epoxy and nanofiller-reinforced nanocomposites. Incorporation of binary nanofillers resulted in better flexure strength, modulus and storage modulus although there was no significance change in glass transition temperature (Tg). FTIR analysis was carried out to study the probable reaction mechanism of epoxy polymer with binary nanofillers. SEM images of the fracture surface of the samples revealed rougher failure surfaces for nanophased samples.

Synergistic Effect of Graphene Nanoplatelets and Nanoclay on Epoxy Polymer Nanocomposites

The prime objective of this study was to fabricate epoxy polymer composite modified with graphene nanoplatelets (GP) and montmorillonite nanoclay (MMT) binary filler materials. Different loading percentages of individual and binary nanofillers were incorporated into an epoxy matrix system to investigate the synergistic effect of nanofillers on composites properties. Dynamic mechanical analysis (DMA) and three point bend test were carried out to investigate the viscoelastic and flexural properties of neat epoxy and nanofillers reinforced nanocomposites. Incorporation of 3 wt. % of MMT and 0.1 wt. % of GP resulted in better flexure strength, modulus and storage modulus although there is no significance change in glass transition temperature (Tg).

Magnetic binary nanofillers

Magnetic binary nanofillers containing multiwall carbon nanotubes (MWCNT) and hercynite were synthesized by Chemical Vapor Deposition (CVD) on Fe/AlOOH prepared by the sol–gel method. The catalyst precursor was fired at 450°C, ground and sifted through different meshes. Two powders were obtained with different particle sizes: sample A (50–75μm) and sample B (smaller than 50μm). These powders are composed of iron oxide particles widely dispersed in the non-crystalline matrix of aluminum oxide and they are not ferromagnetic. After reduction process the powders are composed of α-Fe nanoparticles inside hercynite matrix. These nanofillers are composed of hercynite containing α-Fe nanoparticles and MWCNT. The binary magnetic nanofillers were slightly ferromagnetic. The saturation magnetization of the nanofillers depended on the powder particle size. The nanofiller obtained from powder particles in the range 50–75μm showed a saturation magnetization 36% higher than the one formed from powder particles smaller than 50μm. The phenomenon is explained in terms of changes in the magnetic environment of the particles as consequence of the presence of MWCNT.