Hybrid Nanofillers Research Articles

A comparative study between two novel silicone/graphene-based nanostructured surfaces for maritime antifouling

Two novel superhydrophobic nanocomposite series of polydimethylsiloxane (PDMS) enriched with reduced graphene oxide (RGO) and graphene oxide/boehmite nanorods (GO-γ-AlOOH) nanofillers were synthesized as maritime fouling-release (FR) surfaces. Controlling the nanofillers' structures and distribution in the silicone matrix influenced the self-cleaning and antifouling properties. γ-AlOOH nanorods had a single crystallinity with an average diameter of 10–20 nm and < 200 nm length. A hydrothermal method was used to prepare RGO, while the chemical deposition method was used to synthesis GO-γ-AlOOH nanocomposites for use as fouling-release coating materials. For studying the synergetic effects of graphene-based materials on the surface, mechanical, and FR features, these nanofillers were dispersed in the silicone matrix using the solution casting method. The hydrophobicity and antifouling properties of the surface were studied using water contact angle (WCA), scanning electron, and atomic force microscopes (SEM and AFM). Coatings' roughness, superhydrophobicity, and surface mechanical properties all improved for the homogeneity of the dispersion of the nanocomposite. Laboratory assessments were carried out for 30 days using selected microorganisms to determine the antifouling effects of the coating systems. PDMS/GO-γ-AlOOH nanorod composite had better antibacterial activity than PDMS/RGO nanocomposite against different bacterial strains. This is caused by the high surface area and stabilizing effects of the GO-γ-AlOOH hybrid nanofillers. The PDMS/GO-γ-AlOOH nanorod composite (3 wt%) had the lowest biodegradability percentage (1.6%) and the microbial endurability percentages for gram-positive, gram-negative, and fungi were 86.42%, 97.94%, and 85.97%, respectively. A field trial in natural seawater was conducted to confirm the coatings' FR performance based on the screening process and image analysis for 45 days in a tropical area. The most profound superhydrophobic antifouling nanostructured coating was the homogeneity of the GO-γ-AlOOH (3 wt%) dispersion, which had a WCA of 151° and a rough surface.

Physical Hybrid of Nanographene/Carbon Nanotubes as Reinforcing Agents of NR-Based Rubber Foam.

Natural rubber (NR) foams reinforced by a physical hybrid of nanographene/carbon nanotubes were fabricated using a two-roll mill and compression molding process. The effects of nanographene (GNS) and carbon nanotubes (CNT) were investigated on the curing behavior, foam morphology, and mechanical and thermal properties of the NR nanocomposite foams. Microscope investigations showed that the GNS/CNT hybrid fillers acted as nucleation agents and increased the cell density and decreased the cell size and wall thickness. Simultaneously, the cell size distribution became narrower, containing more uniform multiple closed-cell pores. The rheometric results showed that the GNS/CNT hybrids accelerated the curing process and decreased the scorch time from 6.81 to 5.08 min and the curing time from 14.3 to 11.12 min. Other results showed that the GNS/CNT hybrid improved the foam’s curing behavior. The degradation temperature of the nanocomposites at 5 wt.% and 50 wt.% weight loss increased from 407 °C to 414 °C and from 339 °C to 346 °C, respectively, and the residual ash increased from 5.7 wt.% to 12.23 wt.% with increasing hybrid nanofiller content. As the amount of the GNS/CNT hybrids increased in the rubber matrix, the modulus also increased, and the Tg increased slightly from −45.77 °C to −38.69 °C. The mechanical properties of the NR nanocomposite foams, including the hardness, resilience, and compression, were also improved by incorporating GNS/CNT hybrid fillers. Overall, the incorporation of the nano hybrid fillers elevated the desirable properties of the rubber foam.

Polyamide 66 fibers synergistically reinforced with functionalized graphene and multi-walled carbon nanotubes

Graphene and carbon nanotubes are promising strengthening additives for improving the mechanical properties of polymers. Graphene oxide (GO) and carboxylic multi-walled carbon nanotubes (CMWCNTs) were functionalized through a condensation reaction to graft melamine (M) on the GO and CMWCNTs and form products (M-g-GO and M-g-CMWNTs, respectively) with amino groups. Furthermore, both M-g-GO and M-g-CMWNTs were polymerized in situ with hexanediamine adipate salts to fabricate polyamide 66(PA66)/M-g-GO/M-g-CMWNT nanocomposites. They were melt-spun into fibers with various mass ratios of M-g-GO and M-g-CMWNTs. Transmission electron microscopy confirmed that one-dimensional M-g-CMWNTs could effectively suppress the stacking of individual two-dimensional M-g-GO by bridging adjacent M-g-GO sheets, resulting in a high contact area between the M-g-GO/M-g-CMWNT structures and the polyamide 66 matrix (PA66). Scanning electron microscopy of the fracture surfaces of the composite matrix showed that the M-g-GO/M-g-CMWNT hybrid nanofillers exhibited good dispersibilities and compatibilities. Additionally, the melting and crystallization behaviors of the PA66/M-g-GO/M-g-CMWNT nanocomposite fibers were characterized. The average tensile strength of the PA66/M-g-GO/M-g-CMWNT nanocomposite fibers containing M-g-GO (0.25 wt%)/M-g-CMWNTs (0.25 wt%) was 166% higher than that of pure PA66. Moreover, the tensile strength exhibited a maximum value when the mass ratio of M-g-GO to M-g-CMWNTs was 0.25/0.25. The remarkable synergistic effect between the M-g-GO and M-g-CMWNTs for improving the mechanical properties of polyamide 66 fibers was demonstrated.

Impact of hybrid nanofillers on the structure and property of polypropylene/polystyrene composites based on elongation flow

AbstractThe composites comprised of polypropylene (PP), polystyrene (PS) and hybrid nanofillers were prepared by a novel eccentric rotor extruder based on elongation flow. The morphology, thermal behavior and rheological properties were investigated. The morphology of the PS dispersed phase changed from circular shape of PP70/PS30 blend to microfiber shape of PP/PS/MWCNTs/MMT composite with an increase of the number of the hybrid nanofillers dimensions. The nano‐TiO2 and MWCNTs were mainly located at the interface, did not change the shape of the PS dispersed phase but reduce the size of the dispersed phase. The hybrid nanofillers containing MWCNTs had better modification effect on the improvement of the crystalline ability of PP compared with the hybrid nanofillers without MWCNTs. The introduction of the hybrid nanofillers did not affect the crystal type of PP, but influence the perfection of crystallization of PP. The hybrid nanofillers had a nice enhancement on the thermal stability of the PP/PS blend. Compared with PP, the low frequency G′ of the hybrid nanofillers filled PP70/PS30 composites increased by two orders of magnitude. With an increase of the dimensionality of the hybrid nanofillers, the restriction of the molecular chains relaxation caused by the hybrid nanofillers was enhanced.

Halloysite Nanotubes and Silane-Treated Alumina Trihydrate Hybrid Flame Retardant System for High-Performance Cable Insulation

The effect of the presence of halloysite nanotubes (HNTs) and silane-treated alumina trihydrate (ATH-sil) nanofillers on the mechanical, thermal, and flame retardancy properties of ethylene-vinyl acetate (EVA) copolymer/low-density polyethylene (LDPE) blends was investigated. Different weight percentages of HNT and ATH-sil nanoparticles, as well as the hybrid system of those nanofillers, were melt mixed with the polymer blend (reference sample) using a twin-screw extruder. The morphology of the nanoparticles and polymer compositions was studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The mechanical properties, hardness, water absorption, and melt flow index (MFI) of the compositions were assessed. The tensile strength increases as a function of the amount of HNT nanofiller; however, the elongation at break decreases. In the case of the hybrid system of nanofillers, the compositions showed superior mechanical properties. The thermal properties of the reference sample and those of the corresponding sample with nanofiller blends were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Two peaks were observed in the melting and crystallization temperatures. This shows that the EVA/LDPE is an immiscible polymer blend. The thermal stability of the blends was improved by the presence of HNTs and ATH-sil nanoparticles. Thermal degradation temperatures were shifted to higher values by the presence of hybrid nanofillers. Finally, the flammability of the compositions was assessed. Flammability as reflected by the limiting oxygen index (OI) was increased by the presence of HNT and ATH-sil nanofiller and a hybrid system of the nanoparticles.

Robust, hydrophobic anti-corrosion coating prepared by PDMS modified epoxy composite with graphite nanoplatelets/nano-silica hybrid nanofillers

Despite the significant efforts researchers made, the existing hydrophobic coating systems are still facing challenges such as low durability and weak mechanical robustness. In this study, a nanocomposite coating was fabricated with the hybrid nanofiller reinforcement and modified polymeric resin. The combination of these two reinforcements significantly improved the overall performance of the neat epoxy, with a chemical and mechanical stable hydrophobic property. Compared with the neat epoxy coating, the developed coating was shown by resistance to exposure to corrosive environment and physical abrasion, not reducing the coating's corrosion resistance or hydrophobicity. The addition of graphite nanoplatelets/nano-silica hybrid nanofillers significantly enhanced the anti-corrosion and mechanical properties, such as barrier performance, abrasion resistance, and tensile properties. Meanwhile, polydimethylsiloxane was introduced to modify epoxy resin to improve the hydrophobicity, and the contact angle was increased from 50° to 110°. Results revealed that the integration of these reinforcements had improved the overall performance of the coating, as the coating consisted of outstanding anti-corrosion performance, wear resistance, mechanical strength, water-repellency property, and damage tolerance. Moreover, the facile fabrication method and simple application procedure exhibited its potential toward large-scale commercialization for metallic infrastructures.

PVA/GO-ZnO hybrid nanocomposites: Synthesis, Analysis and Applications

Objective: To prepare Poly vinyl alcohol (PVA) nanocomposites with novel GO-ZnO hybrid Nano filler and test its efficacy and applications. Methods: GO-ZnO hybrid nanocomposite filler was synthesized by modified hummer’s method. Polymer nanocomposite films were prepared by solution casting method. Synthesis of GO-ZnO hybrid procedure is explained in detail. ZnO with average size of 26.74 nm were equally anchored on the GO surface. The properties of the PVA film and the PVA/Graphene Oxide/Zinc oxide composite film were analyzed by electrical, thermo mechanical & spectroscopic analysis. Findings: The results showed that the incorporation of graphene oxide and zinc oxide into the PVA matrix resulted in enhanced mechanical properties and thermal stability of PVA composite films. The tensile strength increases from 3.84 MPa of neat PVA to 10.48 MPa of PVA-0.05% GO-ZnO and Young’s modulus increases from 104.407 to 106.765 MPa. The elongation behavior of the Polymer is increased by the addition of Nano filler and it varies from 15.94 Mpa of pure PVA polymer film to 239.52 MPa of 1% loading -GO-ZnO hybrid filler. Such an enormous improvement in the mechanical properties at such low stacking of GO-ZnO can be credited to a property of GO-ZnO hybrid nano-filler. DC conductivity studies were also under taken on the samples and the conductivity was found to be 2.89510-6 S
cm􀀀1 for 5% loading of nano particle while pure PVA is observed as 9.95210-8. Keywords: GOZnO; Hybrid; filler; nanocomposite; PVA; Electrical Conductivity

Preparation and characterisation of silver nanoparticles/graphene oxide hybrid nanofiller reinforced-polyaniline

ABSTRACT The silver nanoparticle (AgNP) coated graphene oxide (GO) hybrid nanofiller (Ag@GO) reinforced polyaniline (PANI) nanocomposite via in situ polymerisation method is synthesised. Fourier transform infrared (FTIR) spectroscopy analysis revealed the existence of chemical interactions between the Ag@GO hybrid nanofiller and the PANI matrix. The ultraviolet–visible (UV–VIS) spectroscopy showed the presence of a silver nanoparticle peak. The nanostructure morphology of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) established the presence of AgNPs on the surface of the GO nanosheets that successfully reinforced into the PANI matrix. The thermogravimetric-differential scanning calorimetry (TG-DSC) thermograms revealed that the thermal stability of the PANI/Ag@GO nanocomposite was significantly enhanced due to the synergistic effect imparted by the AgNPs, GO, and PANI matrix. The dielectric relaxation spectroscopy (DRS) study indicated that the dielectric behaviour of the PANI/Ag@GO nanocomposite was enhanced because of the strong interfacial interactions existing between the Ag@GO hybrid nanofiller and PANI matrix. Polyaniline/Ag@GO nanocomposite has been prepared via in situ polymerisation method. The results showed that the thermal stability as well as the dielectric properties of the PANI/Ag@GO nanocomposite increases due to the synergistic effect imparted by the GO, AgNP, and PANI, which may be suitable for application in the energy storage devices.

Mechanical Properties of Hybrid Graphene Nanoplatelet-Nanosilica Filled Unidirectional Basalt Fibre Composites.

Basalt fibre (BF) is one of the most promising reinforcing natural materials for polymer composites that could replace the usage of glass fibre due to its comparable properties. The aim of adding nanofiller in polymer composites is to enhance the mechanical properties of the composites. In theory, the incorporation of high strength and stiffness nanofiller, namely graphene nanoplatelet (GNP), could create superior composite properties. However, the main challenges of incorporating this nanofiller are its poor dispersion state and aggregation in epoxy due to its high surface area and strong Van der Waals forces in between graphene sheets. In this study, we used one of the effective methods of functionalization to improve graphene’s dispersion and also introducing nanosilica filler to enhance platelets shear mechanism. The high dispersive silica nanospheres were introduced in the tactoids morphology of stacked graphene nanosheets in order to produce high shear forces during milling and exfoliate the GNP. The hybrid nanofiller modified epoxy polymers were impregnated into BF to evaluate the mechanical properties of the basalt fibre reinforced polymeric (BFRP) system under tensile, compression, flexural, and drop-weight impact tests. In response to the synergistic effect of zero-dimensional nanosilica and two-dimensional graphene nanoplatelets enhanced the mechanical properties of BFRP, especially in Basalt fibre + 0.2 wt% GNP/15 wt% NS (BF-H0.2) with the highest increment in modulus and strength to compare with unmodified BF. These findings also revealed that the incorporation of hybrid nanofiller contributed to the improvement in the mechanical properties of the composite. BF has huge potential as an alternative to the synthetic glass fibre for the fabrication of mechanical components and structures.

Development and mechanical properties investigation of Cu-MWCNT-graphite nanoplatelets hybrid nanocomposites

In this work, Cu-based MWCNT-xGnP hybrid reinforced nanocomposites were fabricated by spark plasma sintering (SPS) and conventional sintering, and their microstructure and mechanical properties were analyzed using several techniques. As compared to sintered pure Cu samples, a remarkable enhancement in physical and mechanical properties is observed in the developed Cu-based hybrid nanocomposites. Hybrids of multiwalled carbon nanotubes and graphite nanoplatelets (MWCNT-xGnP) containing different ratios of MWCNT and xGnP were used as co-reinforcements to strengthen the Cu matrix. The influence of various MWCNT-xGnP hybrid nanofillers having different weight ratios of MWCNT and xGnP on the microstructure, mechanical properties, and wear behavior of Cu-MWCNT-xGnP nanocomposites have been investigated. The highest relative density, better wear behaviour, and hardness were observed in the case of Cu-2 wt% MWCNT50xGnP50 nanocomposite for both conventionally sintered and SPSed nanocomposites.

Micro-Macroscopic coupled modeling for the prediction of synergistic improvement on the thermal conductivity of boron nitride and multi-walled carbon nanotube reinforced composites

The use of hybrid fillers consisting of phycochemically different nanoparticles has been widely investigated to realize synergistic improvement of thermal conduction behaviors. The enhancement of thermal conductivity of composites is often limited by the thermal contact resistance of the reinforcing particles. We prepare a series of hybrid nanofiller reinforced composites composed of two-dimensional boron nitrides and one-dimensional multiwalled carbon nanotubes to investigate the interfacial thermal resistances of the composites by a finite element method. The interfacial thermal resistances calculated by the finite element modeling are implemented into a Mori–Tanaka homogenization scheme to predict the thermal conductivities of the composites with perfect and imperfect interfaces. The prediction by the Mori–Tanaka method was in good agreement with the finite element simulation and the experimental results.

Correction to “Flourishing an Electrochemical Synthetic Route toward Carbon Black-Intercalated Graphene As a Neoteric Hybrid Nanofiller for Multifunctional Polymer Nanocomposites”

Correction to “Flourishing an Electrochemical Synthetic Route toward Carbon Black-Intercalated Graphene As a Neoteric Hybrid Nanofiller for Multifunctional Polymer Nanocomposites”

Multifunctional epoxy composites modified with a graphene nanoplatelet/carbon nanotube hybrid

AbstractEpoxies are a class of thermoset polymers which find use in high performance applications. However, epoxies are inherently brittle and are poor conductors of electricity, which limits their ability to be employed in functional applications. Carbon nanomaterials have attracted considerable attention as filler materials, due to their combination of outstanding properties. In the present work, an epoxy polymer was modified with a hybrid nanofiller, consisting of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) at a mass ratio of 9:1, using three‐roll milling. Addition of 1 wt% resulted in an increase of eight orders of magnitude in the electrical conductivity and a 182% increase in the fracture energy, GIC, of the epoxy. CNTs contributed greatly in the reduction of the percolation threshold, which was 10 times lower than that of conventional GNP/epoxy composites, while the increase in toughness was entirely attributed to the GNPs, predominantly through the mechanism of crack deflection. The toughening contribution of the hybrid nanofiller was theoretically calculated using analytical modeling, which showed excellent agreement between the predicted and experimental values of GIC.

Silk fibroin-Ti3C2TX hybrid nanofiller enhance corrosion protection for waterborne epoxy coatings under deep sea environment

The complex and harsh deep sea environment is the main reason for the failure of the protective coating of marine equipment. However, excellent protective coating is the key to prolong the service life of the equipment under deep sea environment. Ti3C2TX, with high aspect ratio, abundant surface functional groups and excellent mechanical properties, is the suitable candidate nanofiller for coating reinforcement. Herein, we synthesized a novel silk fibroin-Ti3C2TX (SF-Ti3C2TX) hybrid nanofiller as reinforced-additives for improving the anti-corrosion ability of waterborne epoxy coating. Due to the rough surface of SF-Ti3C2TX nanosheets, they have excellent compatibility with the resin matrix and could fill the inherent defects of the coating. The anticorrosion behaviors of as-prepared composite coatings under both of atmospheric pressure and simulated deep sea environment were investigated in detail. Particularly, the composite coating with 0.5 wt% SF-Ti3C2TX sheets showed outstanding corrosion protection (impedance value remained 1.31 × 108 Ω⋅cm2, four orders of magnitude higher than pure EP) after 240 h immersion under 20 MPa hydrostatic pressure. In addition, the interface of coating/steel was not damaged and the coating remained the favorable adhesion strength (3.16 MPa, but that of pure EP only 0.88 MPa) even in the harsh high hydrostatic pressure. Based on the experiment data, we discussed and analyzed the failure process of coatings and explained the corrosion protection mechanism of SF-Ti3C2TX hybrid under simulated deep sea environment.

Flourishing an Electrochemical Synthetic Route toward Carbon Black-Intercalated Graphene As a Neoteric Hybrid Nanofiller for Multifunctional Polymer Nanocomposites

This research work presents a creative and facile process for intercalation of graphite layers with the use of carbon black (CB) spacers, opening up the graphite layers to the nanolevel and producing a hybrid nanostructure. This unique tri-component three-dimensional hybrid structure, which consisted of graphene sheets exfoliated with graphene platelets and CB nanoparticle spacers, was extensively characterized by various sophisticated techniques. This surfactant-assisted electrolysis produced graphene with three layers on average. Disaggregated CB particles keep the graphene layers separated, and the material was structurally stable in water dispersion for more than a week. Such a water-dispersible filler was particularly suitable for a latex-based nanocomposite and typically advantageous concerning the dispersion of graphene-type fillers in polymers. This specifically tailored nanomaterial acted as a proficient functional filler for polymer nanocomposites, and upon incorporation in the styrene-butadiene rubber latex, the filler was brilliantly reinforcing, resulting in a 34% enhancement in the ultimate tensile strength and a 72% increase in the modulus of the rubber. The resultant polymer nanocomposite also unveiled multifunctional properties including a high specific capacitance, such as 244 F/g, and room-temperature magnetic hysteresis with fairly low remnant magnetization. This approach toward the fabrication of metal-free soft magnets comprising a carbon-based nanostructure in a polymeric matrix is scarce, and the study introduces the scope for utilization of similar composite materials in electronic as well as spintronic applications such as flexible supercapacitors even in clinically designed rubber shoes and smart tires.

Multiscale modelling approach for simulating low velocity impact tests of aramid-epoxy composite with nanofillers

The addition of nanofillers to composites has attracted great attention since it adds multifunctional potential. However, the presence of nanofillers inside a composite may cause a more complex response in many situations, e.g. damage accumulation processes, and this response poses extra challenges in the development of reliable numerical approaches. In this work, a three-step multiscale modelling strategy was used to investigate the mechanical properties and damage accumulation of plain-weave aramid-epoxy composites with hybrid nanofillers (carbon nanotubes and graphene nanoplatelets). First, the mean-field method was employed in a microscale model to provide the elastic modulus of the matrix with nanofillers inside. The mechanical properties of such a matrix were then used to predict the global mechanical properties of aramid-epoxy composite using mesoscale models. Finally, those predictions were added as input to a homogeneous material model used to replicate a more complex loading condition (low-velocity tests), for which the direct use of the mesoscale approach is not feasible. In the latter, the mechanical properties of aramid-epoxy composite with nanofillers have been modelled using MAT_162 in LS-DYNA. The agreement between the experiments and simulations with regards to the loading curves and damage phenomena can thus validate the presented approach. In addition, the effect of nanofillers on the mechanical properties and damage evolution of the woven composites in low-velocity impact has been discussed. Finally, the present work can be helpful to improve the awareness in the design of innovative materials by means of predictive modelling approaches.

Application of r-GO-MMT Hybrid Nanofillers for Improving Strength and Flame Retardancy of Epoxy/Glass Fibre Composites

The application of nanomaterials as a strengthening agent in the fabrication of polymer nanocomposites has gained significant attention due to distinctive properties which can be utilised in structural applications. In this study, reduced graphene oxide (r-GO) and montmorillonite (MMT) nanoclay were used as filler materials to fabricate hybrid epoxy-based nanocomposites. The synergistic effect of nanomaterials on flammability and mechanical behaviour of nanocomposites were studied. Results revealed that the addition of nanofiller showcases 97% and 44.5% improvement in tensile and flexural strength. However, an increment in the percentage of filler material over 0.3% exhibits a decremental mechanical property trend. Likewise, the addition of nanofiller increases the nonignition timing of the glass-fibre-reinforced epoxy composites. Fracture surface morphology displays the occurrence of the ductile fracture mechanism owing to the presence of hybrid fillers.

Simultaneous enhancement of mechanical and electrical/thermal properties of carbon fiber/polymer composites via SiC nanowires/graphene hybrid nanofillers

Carbon fiber (CF)/epoxy composites with hybrid nanofillers were prepared by electrophoretic deposition (EPD) of silicon carbide nanowires (SiCnws) on CFs, followed by in-situ grafting of graphene via chemical vapor deposition (CVD). The effects of SiC nanowires/graphene hybrid nanofillers on interlaminar shear strength (ILSS), flexural property, and through-thickness thermal conductivity of CF/epoxy composites were investigated. Due to the incorporation of SiCnws and graphene, the interfacial adhesion and the mechanical interlocking between CF and epoxy were improved significantly, resulting in an increase in ILSS and flexural strength. Moreover, the through-thickness electrical and thermal conductivity increased further with the increasing deposition time of graphene. It can be attributed to the hierarchical thermal conductive chains and networks that were formed by SiCnws deposited on the CF surface and the synergy between SiCnws and graphene. This strategy provides potential new ideas for the thermal management application of epoxy and its composites.

Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

Synthesis and characterization of a novel nickel pillared–clay catalyst: In-situ carbon nanotube–clay hybrid nanofiller from Ni-PILC

This work presents a novel synthesis of a nickel complex to fabricate Ni-pillared clay (Ni-PILC) as the supporting catalyst for the synthesis of carbon nanotubes (CNTs). To identify the synthesized complex structure, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), elemental analysis, and X-ray photoelectron spectroscopy (XPS) were applied to propose the hexanuclear acetato-ammonia nickel(II) acetate complex, with the chemical formula of [Ni6(OOCCH3)11(NH3)·7H2O]+(OOCCH3)−. Various concentrations of the nickel complex (0.5, 1, 2, 3, 4, 5, 6, 7, and 8 CECs) were used to instigate the ion exchange reaction with the montmorillonite (Mt) surface. Chemical vapor deposition was used to synthesize CNTs. XRD, TGA, Raman, SEM, and TEM characterizations were performed on the CNTs to investigate the influence of the catalyst concentration on the properties of CNTs. Depending on the catalyst concentration, the mass loss of CNTs varied from 28% at 0.5 CEC of the Ni catalyst to ~70% at 8 CEC of the Ni complex. XRD indicated that Na+Mt. layers were intercalated with nickel species during the ion-exchange processes, and then delaminated due to the growth of CNTs. The introduction of higher concentrations of the nickel salt into Mt. improved the quality and the synthesis yield.