Nanocomposite Samples Research Articles

Analysis of CNT and rGO Mediation for an Efficient Super-Capacitive Response in Cr-Doped Co3O4 Based Composites

The synthesis of novel and high capacitance electrode materials has attracted much attention over the last few decades to meet the needs of electrode materials in supercapacitors. Cobalt oxide, one of several vanadium oxides, has recently gained popularity due to its unique layered structure, phase transition, and applications in supercapacitors. Here, we present structural, morphological, and electrochemical analysis of Cr-doped Co3O4 nanostructures and their carbon nanotubes/reduced graphene oxide (CNT/rGO) based composites. Hydrothermal and solvothermal routes are followed to prepare the samples. The active material is developed via a polymer-based binder and is used as the electrode in a three-electrode electrochemical system. X-ray diffraction confirms the spinel-type cubic crystal structure, while the stoichiometric elemental contents are verified via an energy dispersive X-ray spectroscopy. Well-shaped layered growth of the nanocomposites is revealed by field emission scanning electron microscopy. The electrochemical analysis is performed using a 2 M KOH electrolyte solution and a three-electrode electrochemical setup. The pure and Cr-doped nanocomposite samples reveal a pseudo capacitive behavior in all samples. The systematic capacitive and resistive response of the samples has also been presented in this report. The aforementioned attributes make the synthesized specimen a potential candidate for an electrode material.

Effect of Phosphorus-Nitrogen based Flame-Retardant Combined with Zinc Borate on Thermal Stability and Flame Retardancy of Epoxy Clay Nanocomposites

A phosphorus-nitrogen containing 6,6'-(piperazine-1,4-diyl)bis(6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (DOPO-PZ) flame-retardant was synthesized and its effect combined with zinc borate (ZnB) and nanoclay (NC) on thermal stability and flame retardancy of epoxy resin was studied. Various epoxy composites containing DOPO, DOPO-PZ, ZnB and NC using curing agent diaminodiphenylsulfone (DDS) were prepared. The X-ray diffraction (XRD) and transmission electron microscope (TEM) micrographs of the composites showed intercalated nanostructure of epoxy-clay nanocomposites. In thermogravimetric analysis (TGA), pure epoxy gave 3.4% char yield at 700 ºC in nitrogen atmosphere, while in case of EP/DOPO-PZ/ZnB/NC sample having 1% phosphorus content, 5 wt.% zinc borate (ZnB) and 3 wt.% nanoclay (NC), the char yield is increased to 24.0%. Differential scanning calorimetry (DSC) study showed decrease in the glass transition temperature (Tg) on the addition of flame-retardant due to plasticization effect and increase in Tg on addition of nanoclay due to formation of nanostructure of epoxy composites. The EP/DOPO-PZ/ZnB/NC nanocomposite sample exhibited a limiting oxygen index (LOI) value of 29.2% and passed the UL-94 test with a V-0 rating and thus achieved a sufficient flame retardancy.

Jute and Flax Fiber Composites Enhancement through Carbon Nanotube Filler

This investigation primarily focuses on enhancing the sustainable jute/flax/epoxy nanocomposite with the use of carbon nanotubes (CNTs) as filler. The flax and jute natural fibres were treated with sodium hydroxide solution. The compression moulding technique was preferred for better fabrication. The CNTs were thoroughly mixed with epoxy resin with the help of a ball milling-type mixture. The nanocomposite samples were prepared by varying the reinforcement and filler content. Jute fibre varied from 59 to 99 wt%, Flax Fiber varied from 0 to 40 wt% and the filler was maintained as constant of 1 wt%. The five types of laminated and fabricated composites were characterized in terms of tensile strength, flexural strength and modulus of elasticity. The SEM examinations were carried for the composite samples to analyse the fibre diameter (µm), CNT dispersion and interfacial adhesion. The results revealed that the sample fabricated with 69 jute fibre, 30 wt% flax fibre, and 1 wt% CNT filler outperformed with 60.1 MPa tensile strength, 79.3 MPa flexural strength, 8.1 GPa modulus of elasticity.

Investigation of thermodynamical, electro-optical and dielectric properties of nematic liquid crystals dispersed with low-concentration barium titanate nanoparticles

ABSTRACT A liquid crystals nanoparticles composite was prepared by dispersing barium titanate nanoparticles (BT-NPs) into a multi-component liquid crystalline material having wide range room temperature nematic phase. The thermodynamic, optical textures, electro-optical and dielectric properties of the composite sample were studied along with pristine materials. Isotropic to nematic phase transition temperature was enhanced for nano-composites as observed from thermodynamic, optical textures and dielectric investigations. Effect of BT-NPs dispersion on various display parameters of nematic liquid crystals, namely, threshold voltage, dielectric anisotropy, DC conductivity and splay elastic constant has been explored. A relaxation mode in kHz frequency range has been observed for pure and nano-composites samples, which varies with temperature and follows Arrhenius behaviour. DC conductivity enhances approximately fivefold for BT-NPs dispersed samples. The host liquid crystalline material has nematic ordering which supports alignment of BT-NPs parallel to the nematic director which consequently improves thermal stability, dielectric and electro-optical parameters of the nano-composite system.

Influence of graphene nanoplates and titanium diboride particulate on wear and interfacial bonding properties of sintered aluminium alloy composites

Graphene has been considered an appropriate reinforcing filler for aluminium/titanium metal matrix composites due to its outstanding strength and stiffness and its exceptional thermal and electrical properties. The variable concentrations of graphene nanoplates (GNPs) was considered in this research, such as 2 %, 4 %, 6 % and 8 %, for determining wear properties and interface bonding aluminium alloy composites. The graphene-reinforced Al 7075/10 % TiB2 hybrid nanocomposite samples were produced using ball milling and pressure-less vacuum sintering process. The wear loss was investigated for all the variable graphene concentration samples with respect to wear load and sliding distance by pin-on-disk method and optimum concentatrion of GNPs was obtained by design of experimental (DOE) analysis. Further, Field Emission Scanning Electron Microscopy (FESEM), Elemental mapping, Energy Dispersive X-ray (EDX), and microhardness tests were utilized to analyze the graphene-reinforced Al 7075/10 % TiB2 hybrid nanocomposites, It was concluded that the wear resistance and microhardness of Al/10 % TiB2/4 % GNPs increased by 71.3 % and 17.6 %, respectively, compared with non-hybrid aluminium alloy materials. Moreover, a Transmission Electron Microscope (TEM) has been used to investigate the interfacial strength of aluminium alloy composites. The wear loss characteristics was also optimized using and central composite design (CCD) of response surface methodology (RSM).

Silver nanoparticles induced enhanced stability, dielectric anisotropy, and electro-optical parameters of a nematic liquid crystalline material 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzene

Nanocomposites of 4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzene nematic liquid crystals and silver nanoparticles have been prepared. UV absorption spectroscopy, Fourier transform infrared and Raman spectroscopies were used to characterize the morphology of silver nanoparticles (Ag-NPs). Thermodynamic, optical, and dielectric studies have been done to explore the change in the physical parameters of the composites with respect to the pure sample. Due to dispersion of silver nanoparticles, transition temperature, associated enthalpy and order parameters of the nanocomposites have increased. Dielectric study shows enhanced dielectric anisotropy for Ag-NPs dispersed nanocomposites. The relaxation frequency of an observed mode has shifted towards high frequency region for the nanocomposites. Optical band gap for pure and nanocomposites samples has been estimated from UV absorption peaks and it is found that optical properties of the nanocomposites are almost invariant. Threshold (switching) voltage, rotational viscosity and splay elastic constant for pure and dispersed samples have also been obtained from electro-optical studies.

Fabrication of g-C3N4 nanosheet anchored NiZn2O4 nanocomposites for enhanced photocatalytic dye degradation

NiZn2O4 and NiZn2O4/g-C3N4 nanocomposite samples were successfully prepared by hydrothermal method. The prepared samples were analyzed by different approaches and the energy band gaps for the g-C3N4, NiZn2O4 and NiZn2O4/g-C3N4 samples are 2.72, 3.1 and 2.87 eV respectively. The observed decrease in the energy band gap (Eg) value of prepared NiZn2O4/g-C3N4 extends its superior photocatalytic activity in the visible light region. When compared to the pure NiZn2O4, g-C3N4 sample, the NiZn2O4/g-C3N4 nanocomposite has an excellent degradation ability against the MB dye, with a degradation efficiency of 96.06 % at 180 min under UV– Visible light irradiation.

An Investigation into the Effect of Length Scale of Reinforcement on the Cryogenic Response of a Mg/2wt.%CeO2 Composite

The present study attempted for the first time an investigation on the effect of deep cryogenic treatment in liquid nitrogen (LN) on magnesium–cerium oxide (Mg/2wt.%CeO2) composites containing equal amounts of different length scales (micron and nanosize) cerium oxide (CeO2) particles. The disintegrated melt deposition method was used to synthesize Mg-2CeO2 micro- and nanocomposites, followed by hot extrusion as the secondary processing. Further liquid nitrogen treatment was performed at a cryogenic temperature of −196 °C. The combined effects of cryogenic treatment and reinforcement length scale on physical, mechanical, and thermal behaviors were studied. The results indicate that LN-treated micro- and nanocomposite samples exhibit, in common, a reduction in porosity, similar grain size, and a limited effect on the original texture of the matrix. However, microhardness, 0.2% Compressive Yield Strength (CYS), failure strain, and energy absorbed increased for both micro- and nanocomposite samples. Overall, results clearly indicate the capability of deep cryogenic treatment with LN to positively diversify the properties of both micro- and nanocomposite samples.

Effect of Carbon Nanotube Reinforcement on Creep and Recovery Behavior of Additively Manufactured Polymers: An Experimental and Prediction Study

In this study, one of the most frequently used polymeric materials in fused deposition modeling (FDM) acrylonitrile butadiene styrene (ABS) is reinforced with different amount of carbon nanotubes (CNTs). Thermogravimetric analysis and differential scanning calorimetry analysis are applied to examine thermal degradation behavior of produced nanocomposite filaments. Specimens are manufactured by fused deposition modeling by using produced nanocomposite filaments. Tensile, creep and viscoelastic-viscoplastic behaviors of FDM-printed nanocomposite samples are investigated by conducting tensile, creep and loading–unloading tests under different strain rates and strain levels. Morphology of 3D printed samples is examined through scanning electron microscopy. Void densities which plays important role in mechanical behavior of additively manufactured samples are determined via ImageJ and CNT reinforcement on void densities are investigated. Data obtained from tests are used in system identification process, and multi-input–single-output model structures are proposed for the prediction of tensile, creep and recovery behaviors of 3D printed nanocomposite materials.

Experimental and numerical investigation of nanomaterial-based structural composite

Abstract In this work, we discussed multi-phase composites fabrication and analytical as well as experimental analysis. Shear mixing of multi-walled nanotube (MWCNT) and epoxy is used to create nanocomposites. Ultrasonication, magnetic stirring, and moulding using the hand layup technique were the procedures used for sample preparation. Curing and cutting were performed as well, all in accordance with ASTM standards. This research uses an experimental method for assessing material qualities and backs up its findings with an analytical one for verification. It can be shown that the outcomes of both experiments and analyses are consistent. The structural analysis of a composite sample is probed by using a further analytical validation strategy. In this research, we examined the effects of varying the MWCNT content of the matrix. The tensile strength was shown to rise up to 0.5% MWCNT content in the matrix. For 0.7% MWCNT reinforcement in the matrix, tensile strength drops as a result of agglomeration. This research also explored the use of ANSYS for critical buckling analysis on many different multi-phase nanocomposite samples. The critical buckling resistance capability of the various configurations of composite materials was examined, and the model’s efficacy was shown via validation against existing literature.

Enhancing the performance of PVC/PMMA polymer blend through hybrid nanofiller of TiO2 NPs/GNPs for capacitive energy storage applications

Polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) have been used as polymeric matrices for the synthesis of polymeric nanocomposite films that incorporate titanium oxide nanoparticles (TiO2 NPs) and graphite nanoplatelets (GNPs) as nanofillers. Based on TEM studies, TiO2 nanoparticles have a tetragonal anatase phase, ranging in size from 15 to 60 nm, whereas GNPs have a nanoplatelet-like shape, varying in thickness from 10 to 20 nm. XRD analysis shows that PVC/PMMA polymer nanocomposite samples have less crystallinity when added with TiO2 NPs and GNPs. Infrared Fourier analysis (FT-IR) indicated a complex interaction between the PVC/PMMA blend and both GNPs and TiO2 NPs. The UV/visible spectrum of the PVC/PMMA blend showed two absorbance peaks at 279 and 223 nm which may result from the n→π* and π→π* transitions. Moreover, optical bandgaps were reduced for both indirect and direct transitions when TiO2 NPs and GNPs were added. AC electrical conductivity and dielectric properties of the samples were measured at room temperature. Results indicated a significant increase in conductivity after filling from 2.6 x 10−14 S/cm for pure PVC/PMMA to 7.3 x 10−6 S/cm for PVC/PMMA-TiO2/GNPs nanocomposite. In addition, high nanoparticle concentrations lead to higher composite dielectric loss and dielectric constants. These findings suggest the possibility of using the prepared nanocomposites in capacitive energy storage and optoelectronic devices.

Optimization of wire electrical discharge machining parameters of AA6063/Al2O3 nanocomposite processed by multi axial forging using Taguchi technique

AbstractThe aluminium based matrix composites have excellent mechanical properties to use in automobile, aerospace, aviation, and military industries. The aluminium based matrix composite possesses desired characteristics like specific strength, excellent rigidity and wear resistance. The stir casting technique was used to fabricate the nanocomposite of AA6063 alloy reinforced with 5 weight % nano aluminium oxide particulate. To improve the microhardness of as cast and aluminium based nanocomposites, multiaxial forging was performed up to three passes for grain refinement. Wire electrical discharge machining was used to machine both as cast and “AA6063/Al2O3” (zero and three multi axial forging pass). The machining characteristics of samples were statistically examined using the Taguchi technique. The material removal rate in three multiaxial forging pass nanocomposite sample increased as peak current increases. However, increasing the pulse off time resulted in the lowest material removal rate. The surface roughness was found to be higher in the nanocomposite sample in comparison to as cast. The machining on nanocomposite multiaxial forged sample has a greater impact as compared to as cast. After machining, scanning electron microscopy was used to examine the surface morphology. The presence of different elements in the castings was validated using energy dispersive X‐ray spectroscopy.

Detailed investigation of the structural and electrical properties of ZnO/Fe3O4 nanocomposites

The nanocomposites with the formula (1-x)ZnO+xFe3O4 (x = 0, 0.01, 0.03, 0.05, 0.7 and 0.09) were prepared using the sonomechanical method, while the pristine ZnO and Fe3O4 were prepared using the co-precipitation technique. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and a high-resolution broadband impedance analyzer were used to examine the structural, microstructure, and dielectric properties of the investigated samples. XRD analysis assures the wurtzite hexagonal structure of ZnO for all nanocomposite samples. The FTIR showed the existence of a functional group of ZnO and Fe3O4. The ac conductivity, dielectric constant (ε′), dielectric loss (ε′), electric modulus, impedance, and Nyquist plot were studied as a function of frequency and at different temperatures. The results show that the small concentration of Fe3O4 affects the ac conductivity and dielectric properties. The Koops phenomenological theory and the Maxwell-Wagner interfacial model were used to analyze the observed dielectric dispersion. The analysis of modulus and impedance results indicated the existence of non-Debye relaxation and the involvement of both grains and grain borders in polarization. The impedance study reveals that just one semicircle is observed in all samples, indicating that the influence of grain boundaries is more significant than the contribution of grains.

Nano-titania and carbon nanotube-filled rubber seed oil as machining fluids

Machinists face persistent challenges in managing heat dissipation during cutting operations. To address this issue in an environmentally conscious manner, there is a need for nanofluids crafted from sustainable, eco-friendly materials. This study delves into developing nanocomposites (NCs) of nano-titania (nTiO2) derived from Terminalia catappa leaves and carbon nanotubes (CNTs) in varying compositions (nTiO2/CNTs: 90/10, 70/30, and 50/50 wt%). These NCs underwent comprehensive characterization using techniques such as BET, HRSEM/EDX, HRTEM, XRD, and FTIR. The aim was to evaluate their stability as potential fillers in rubber seed oils (RSOs) for machining operations. Furthermore, the homogenous NC samples in RSO revealed distinct polycentric rings, indicating the dispersion of nTiO2 in CNTs, forming Ti–O–C and Ti–O–Ti networks. XRD analysis identified anatase diffraction peaks, though the CNT peaks were less distinct due to overlap with TiO2 peaks. This successful fusion addresses challenges related to individual fillers, ensuring stable nanosuspension formulation. The TiO2/CNTs (50/50 wt%) NC emerged as particularly effective in dissipating heat from machining interfaces. The study highlights the nanomaterials' high thermal stability, complementing the abundant unsaturated fatty acids in RSOs to create advanced nanofluids for improved machining. The substantial pore volume and stable nanosuspension formation observed are attributed to the large surface area aiding heat removal. Ultimately, the reinforced RSO with nTiO2/CNTs shows promising potential for safe and efficient machining applications.

One-step preparation of silver nanoparticle containing polymer nanocomposites via stereolithography technique

As a technique that uses ultraviolet light to cure photo-polymers layer by layer with high spatial resolution and surface quality, stereolithography (SLA) allows for precise process control and optimization for various UV-curable polymers and their nanocomposites with various nanoparticles. In this study, UV-curable polymer nanocomposites were prepared with the addition of different contents of silver nitrate via SLA technique for use in antibacterial applications. In-situ synthesis of AgNPs was achieved during the SLA process without any additional treatments. The effect of AgNO3 addition on the curing of the resin and the mechanical properties of the nanocomposite specimens were investigated. To understand the fracture mechanism of the nanocomposite samples, the fractured surfaces of the samples were evaluated by SEM, and the AgNO3 content of the nanocomposite was evaluated by EDX. The nanocomposites containing 0.3 wt. % AgNO3 exhibited improved mechanical properties. Further increasing the AgNO3 content to 3 wt. % led to deterioration in the physical and mechanical properties of the polymer nanocomposites.

Effects of Halloysite Nanotube (HNT) on the Cd<sup>2+</sup> Adsorption Capacity of Cellulose Acetate (CA) Thin Film Membranes

This paper aims to investigate the effects of adding and increasing the concentration of halloysite nanotube (HNT) to a cellulose acetate (CA) membrane which is produced through non-solvent-induced phase separation via hand casting. Different characterization tests are performed on the nanocomposite samples: Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), and Atomic Absorption Spectroscopy (AAS). The addition of the filler itself increases the presence of peaks and valleys on the surface of the nanocomposite membrane. The 5% HNT nanocomposite membrane has the largest peaks and valleys-both in size and number. Using the following contact times: 2, 4, and 6 hours, the adsorption capacity of the CA-HNT membranes is obtained with the aid of AAS results. The 5% HNT sample leads to a nanocomposite membrane with a higher adsorption capacity relative to that of a pure CA membrane.

A Study on the Optimization of Nano-B4C Content for the Best Wear and Corrosion Properties of the Al-Based Hybrid Nanocomposites

This investigation is dedicated to producing hybrid nanocomposites based on AA2024, achieved through the utilization of powder metallurgy methods encompassing mechanical milling and hot pressing. The research focused on studying how changes in B4C content influence the mechanical, wear, and corrosion behavior of AA2024/h-BN/B4C hybrid nanocomposites. The findings revealed that as the B4C content increased, the relative density values decreased, and higher porosity values were observed in the hybrid nanocomposite samples. Among the tested samples, the hybrid nanocomposite with 4 wt% B4C exhibited the most favorable properties. It demonstrated significantly higher hardness and ultimate tensile strength compared to AA2024 matrix alloy, with values of 161 HB and 372 MPa, respectively. In contrast, the matrix alloy showed hardness and ultimate tensile strength values of 105 HB and 237 MPa, respectively. Furthermore, the wear resistance of hybrid nanocomposite with 4 wt% B4C displayed approximately 14 times greater wear resistance under 40 N load compared to the unreinforced AA2024 matrix alloy. The corrosion test results have revealed that the corrosion resistance of the hybrid nanocomposite reinforced with 4wt% B4C is nearly 47% higher compared to the corrosion resistance of the unreinforced AA2024 alloy. This nanocomposite exhibits the highest polarization resistance of 5.21 Ω.cm2.

Graphene oxide-wrapped tungsten trioxide for adsorptive removal of methylene blue

Graphene oxide (GO) is a graphene derivative, but different from graphene (Gr), it has a high dispersibility and a high potential to composite with other materials. In order to reveal the effect of graphene oxide (GO) on the enhancement of methylene blue (MB) adsorption, in this study, different GO contents (0, 0.3, 0.5, and 0.7 wt%) were in situ composited with tungsten oxide nanostructures prepared by a simple one-pot hydrothermal method. The physicochemical analysis implies that the in situ compositing helps create a strong interaction between GO and platform material - tungsten oxide. As the GO content increased from 0 to 0.7 wt%, the average crystallite size decreased slightly from 26.7 nm to 24.0 nm, while the microstrain increased from 0.31 to 0.53 %, respectively. Both pristine and nanocomposite samples showed good adsorption capacity with methylene blue (MB), which increases with GO content in the nanocomposites. The sample composited with 0.7 wt% GO showed the highest adsorption activity with the highest adsorption capacity of 76.1 mg/g after 150 min at the optimum condition (15 mg absorbent and 100 ml of MB 30 mg/ml). The MB adsorption kinetics is consistent with the second-order kinetics model with the maximum rate of 2.3 × 10−3 g/mg·m at the optimum condition, while the adsorption isotherm is well described by the Langmuir model with the Langmuir adsorption constant of 0.37 l/mg. These results show that the one-pot hydrothermal method is a facile and efficient method for in situ preparing the Gr-based nanocomposite absorbent.

Mechanical recycling and electro‐thermal welding of epoxy vitrimer nanocomposites

AbstractVitrimers constitute a new class of recyclable thermosets based on the incorporation of associative dynamic covalent bonds, such as disulfide bonds, into the crosslinked matrix. These reversible bonds usually require excess dynamic bonds to confer proper self‐healing and recycling capabilities to the thermoset. In that way, we manufacture epoxy resins cured with 4‐aminophenyl disulfide (AFD) in a stoichiometric ratio, and with 10 and 20 wt% of AFD excesses to analyze the effect of composition on resin properties. Beyond the neat vitrimers analysis, we manufacture nanocomposites doped with carbon nanotubes (CNT) to obtain electroactive vitrimers. These epoxy resins and nanocomposites can be mechanically recycled by milling and hot‐pressing. The recycled nanocomposites conserve partially CNT integrity and dispersion. Even more, recycled nanocomposites with AFD excesses maintain the mechanical strength of the pristine nanocomposites. Vitrimer nanocomposite samples can be also electrically welded, due to their heating by the Joule effect, through a relatively low voltage application, and therefore with low energy consumption, to obtain a monolithic specimen. In summary, the manufactured epoxy vitrimers and nanocomposites are recyclable and sustainable epoxy materials, which can be processed and reprocessed using technologies easily implementable, fast, and with low energy consumption.Highlights Electroactive and re‐processable vitrimer nanocomposites are manufactured. Nanocomposite vitrimers show conductivities similar to conventional epoxies. Bond exchanging temperatures can be reached by Joule heating. CNT addition enhances disulfide exchanges and thermo‐mechanical recyclability. Electrothermal welding of vitrimer nanocomposites is successfully tested.

Physicochemical study of natural zeolite modified with lavender essential oil

Zeolite-containing nanocomposites as candidates for Lavender oil delivery systems were investigated. The nanocomposite samples and lavender oil delivery systems were investigated by pore size distribution and X-ray diffraction (XRD), the specific surface area with Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FT-IR) spectrometer, energy-dispersive spectroscopy (EDX) analysis and Scanning Electron Microscopy (SEM). These initial results could significantly contribute to the further development of applications for lavender essential oil delivery systems based on natural zeolites as innovative bioactive products.