Multi-walled Carbon Nanotubes Support Research Articles

Comparative study of different carbon reinforcements at different length scales on the properties of polyvinyl alcohol composites

AbstractComparative studies on the mechanical behavior of the composites of polyvinyl alcohol (PVA) polymer with different carbon fillers such as multiwalled carbon nanotube (MWCNT), functionalized CNT (f‐CNT), and short carbon fiber (Cf), having similar geometry (1D) but different length scale, have been carried out. Microstructural analysis reveals better distribution of second phases with f‐CNT and Cf compared with MWCNT. Fourier‐transform infrared spectra indicate the interaction of functional groups of CNTs with the polymeric chain of PVA. X‐ray diffraction analysis shows improvement of crystallinity upon addition of carbon filler. Defect analysis of carbon reinforcement is carried out using Raman spectroscopy. The strength of the composite is increased by 138% with MWCNT reinforcement, by 201.8% with f‐CNT reinforcement, and by 87.9% with Cf reinforcement. The fractographs show pullout, branching, and bridging as strengthening mechanisms for MWCNT and f‐CNT in the PVA matrix, whereas mainly pullout as strengthening mechanism for Cf–PVA composite.

Effect of using multiwall carbon nanotube reinforced epoxy adhesive in enhancing glass fiber reinforced polymer composite through cocure manufacturing technique

AbstractThe high‐performance epoxy‐based cocure manufacturing technique has been used to join composite structures such as wings, frames, and ribs in aerospace applications. The present study aims to examine the influence of multiwall carbon nanotubes (MWCNTs) addition on mechanical and free vibrational behavior of glass fiber reinforced polymer composites fabricated through cocure manufacture technique. The experimental results revealed that the addition of 1 wt.% of MWCNTs enriched the tensile and flexural properties of cocured composites by 27.8% (344 Mpa) and 26.16% (379.12 Mpa), respectively. Shear analysis depicted that 0.25 wt.% MWCNT reinforcement significantly enhanced the shear strength of cocured lap joints by 63.8% (16.79 MPa). The scanning electron microscopy and atomic force microscopy indicated that homogenous dispersion of MWCNTs enriched the interfacial bonding, deviated the crack path, and formed uneven surfaces. A comparison between the failure mode of neat and modified adhesive demonstrated the effective presence of MWCNTs in changing the adhesive failure mode of cocured composite to cohesive. Thus, it enhanced the failure strength of cocured composites. The experimental free vibrational analysis affirmed that addition of 1 wt.% MWCNTs enhanced the fundamental natural frequency whereas, lower wt.% MWCNT addition increased the cocured composites' inherent damping due to higher‐level formation of agglomeration area in the composite. Thus, it increased the stress level and minimized the bonding between fiber and matrix.

Study on Properties of Multi Walled Carbon Nanotube Reinforced Aluminum Matrix Composite through Casting Technique

Composite materials are defined as material systems consisting of mixture of or combination of two or more micro constituents insoluble in each other and differing in form and or material composition. In this study Metal Matrix Composite (MMCs) has been produced using stir casting method for performing the mechanical properties. Most of the engineering industries want light and better mechanical properties of components; this can be achieved by MMCs of Aluminium because of its excellent performance. In this research work we fabricate the Aluminium by liquid route. Here Al 7075 is used as a base metal and Multi Walled Carbon Nanotubes (MWCNT) used as sub metal with various percentages. Experiments were conducted to analyze microstructure, hardness & tensile strength. By using optical microscope and Scanning Electron Microscope (SEM) we analyze the sample specimens are well dispersion in MWCNT with AA 7075. Hardness and tensile strength increases with increasing of wt. %. Hardness of material increases with increase in percentages of MWCNT, whereas tensile strength of the material increases with increase in percentages of MWCNT and Elongation reduces

Microstructural and mechanical studies of multi-walled CNTs/Mg composite fabricated through FSP

Flourishing trend of aerospace and automobile applications endlessly demand for significantly higher encouraging performance lightweight materials. Potentially Magnesium got limelight for having lightweight physical property and thus has great potential to energize mechanical property by making its composites. Therefore, magnesium composite was fabricated by incorporating multi-walled carbon nanotubes (MWCNTs) as reinforcement into magnesium matrix at volume percentages 10, 20 and 30, respectively through friction stir processing (FSP). Furthermore, the effect of MWCNTs was investigated and validated through various characterizations. The X-ray diffraction (XRD) investigation ensured the existence of parent phases of materials. The mechanical properties of MWCNT/Mg composites such as tensile strength and micro hardness were investigated and found optimum results at 20 vol% MWCNTs. The optimum upsurge in tensile strength attained was twice relative to pure magnesium. Moreover, the wear test was conducted to analyse the wear behaviour. Since the grain growth was obstructed by MWCNTs reinforcement and encouraged to enrich grain refinement, thus the wear resistance was improved. However, the mechanical properties deteriorated beyond 20% due to clustering of reinforcement revealed from fracture study.

Fabrication and Characterization of Cold-Pressed and Sintered Aluminium - MWCNT Composites

In the present article aluminium matrix composites were fabricated by cold pressing and sintering technique. Multi-walled carbon nanotube (MWCNT) with various weight percentage 0.5, 1.0, 1.5 and 2.0 were added as a reinforcement to aluminium (Al) matrix. A planetary ball mill was used for mechanical alloying and even dispersion of carbon nanotubes (CNTs) in aluminium matrix. Tin (Sn) with 1.0 weight percent was used in composite to incite the sintering. The sintering was carried out at 500°C inside a tube furnace in an argon atmosphere. The morphology and structure of CNT and Al-Sn-CNT composite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. The effect of MWCNT reinforcement on microhardness and wear properties of Al-Sn-CNT composite was investigated. The hardness of composites was improved significantly with increase in CNT fraction. The reduction in the coefficient of friction and improvement in the wear resistance of the Al-Sn-CNT composite was noticed with the increase in percentage of CNTs in the composite.

Experimental Novel Investigation of Electrostatic Charged Multi Walled Carbon Nanotubes Reinforced Epoxy Based Polymer Composite

Experimental Novel Investigation of Electrostatic Charged Multi Walled Carbon Nanotubes Reinforced Epoxy Based Polymer Composite

The influence of processing conditions on tensile properties of wholly thermoplastic composites reinforced with nanotubes

AbstractThis paper is concerned with novel wholly thermoplastic composites (WTCs) reinforced with supercritical carbon dioxide‐aided exfoliated multi‐walled carbon nanotubes (MWCNTs) and the enhancement of mechanical properties. The bicomponent in situ injection molded plaques consist of polyamide 6 (PA6) and microfibers of thermotropic liquid crystalline polymer (TLCP) with miss‐matched melting temperature. Multiple mixing histories with MWCNTs and processing temperatures were studied and tested for minimizing matrix thermal degradation and maximizing tensile properties of the multi‐scale WTCs. The optimum in situ injection molding temperature was found at 300°C with melt blending nylon 6 matrix and exfoliated MWCNTs in advance. Exfoliated MWCNTs acted as bridging elements between the TLCP and the nylon 6 matrix, which lead to effective stress transfer from the nylon 6 matrix to the TLCP fibrils. Compared to the WTCs without MWCNTs reinforcement, tensile modulus and tensile strength in longitudinal and latitudinal directions were both improved. Furthermore, with the reinforcement of TLCP and exfoliated MWCNTs, the tensile modulus and tensile strength of nylon 6 were enhanced by 173% and 35% in the fluid flow direction, respectively. These experimental results for 20 wt% TLCP/PA6 were even better than the mechanical properties of 20 wt% carbon fiber (CF)/PA6 reported in the literature.

Development of a new analytical framework for deflection analysis of un-symmetric hybrid FRP laminates with arbitrary ply arrangement and MWCNT reinforcement

This research explores the influence of various parameters on the cured shape of hybrid fiber reinforced polymer (FRP) laminates. A new analytical framework based on micromechanics models is developed in MATLAB containing all formulations for deflection analysis of laminated composite structures with fibrous and multi-walled carbon nanotubes (MWCNTs) reinforcements. After verifying the reliability and accuracy of represented computational model, we studied the influence of mold radius on the cured shape of laminates with cross-ply and non-cross-ply arrangements. The effects associated with shear strain deformation term are similarly examined for both ply arrangements. Next, the curvature response of several arbitrary configurations as well as reinforcing with different MWCNT percentages are studied. Finally, some points are suggested regarding the optimal design of hybrid FRP composite structures considering curvature response.

Comparison of Carbon Supports in Anion Exchange Membrane Fuel Cells.

Anion exchange membrane fuel cells (AEMFCs) are attractive alternatives to proton exchange membrane fuel cells due to their ability to employ nonprecious metals as catalysts, reducing the cost of AEMFC devices. This paper presents an experimental exploration of the carbon support material effects on AEMFC performance. The silver (Ag) nanoparticles supported on three types of carbon materials including acetylene carbon (AC), carbon black (CB), and multiwalled carbon nanotube (MWCNT)—Ag/AC, Ag/CB, and Ag/MWCNT, respectively—were prepared using the wet impregnation method. The silver loading in the catalysts was designed as 60 wt.% during the synthesizing process, which was examined using thermogravimetric analysis. The elemental composition of the prepared Ag/AC, Ag/CB, and Ag/MWCNT catalysts was confirmed using X-ray diffraction analysis. The nanoparticle size of Ag attached on carbon particles or carbon nanotubes, as observed by scanning electron microscopy (SEM), was around 50 nm. For the performance tests of a single AEMFC, the obtained results indicate that the maximum power density using Ag/MWCNT as the cathode catalyst (356.5 mW·cm−2) was higher than that using Ag/AC (329.3 mW·cm−2) and Ag/CB (256.6 mW·cm−2). The better cell performance obtained using a MWCNT support can be ascribed to the higher electrical conductivity and the larger electrochemical active surface area calculated from cyclic voltammetry measurements.

Določanje mehanskih lastnosti Al/MWCNT kompozitov, ojačanih z bakrom oplaščenimi večstenskimi ogljikovimi nanocevčicami (MWCNT)

Določanje mehanskih lastnosti Al/MWCNT kompozitov, ojačanih z bakrom oplaščenimi večstenskimi ogljikovimi nanocevčicami (MWCNT)

The Effect of the Processing Parameters on the Properties of the Liquid Phase Spark Plasma Sintered 80Fe-20(Al + MWCNT) Magnetic Metal Matrix Nanocomposites

In this paper, the liquid phase sintering was performed using spark plasma sintering to produce iron (Fe: 80 vol%)–aluminum (Al)–multi-walled carbon nanotubes (MWCNTs) magnetic hybrid metal matrix nanocomposites. The properties of the nanocomposites were investigated by considering different parameters of materials processing. The reinforcement of MWCNT with a content of 0–2 vol% did not affect the saturation magnetization of the nanocomposites but increased the coercivity and reduced both the electrical resistivity and the mechanical transverse rupture strength. It was found that milling the powders for 24 h resulted in composite with high saturation magnetization (148.820 A·m2/kg) and high coercivity (2175.6 A/m) but further milling time had reduced the values of magnetic properties. The mixture of Fe nanoparticles and Fe microparticles in composites with a nanoparticles-to-microparticles volume ratio of 1:1 has led to the enhanced saturation magnetization up to 157.820 A·m2/kg and reduced the coercivity of 50.20% in comparison with the Fe nanoparticles based nanocomposites. That mixture exhibited good electrical resistivity but caused the reduction of mechanical strength. The post-sintering annealing has significantly improved the magnetic softness of the composites by reducing the coercivity up to 854.30 A/m and increased the saturation magnetization.

Effect of reinforced multiwall carbon nanotubes on the damping characteristics of Sn-Ag-Cu lead-free solder

Sn-3Ag-0.5Cu solder exhibits an internal friction peak, which corresponds to the sliding of the grain boundaries, in the heating internal friction curve. The activation energy of the internal friction peak increases with the number of reinforced multiwall carbon nanotubes (MWCNTs) because the Sn-3Ag-0.5Cu solder has a finer grain size and more abundant sliding grain boundaries after reinforcement with MWCNTs. The activation energy of the high-temperature damping background (HTDB) of the Sn-3Ag-0.5Cu solder decreases after reinforcement with MWCNTs, indicating that MWCNT reinforcement accelerates the dislocation diffusion process and creep process at the HTDB temperature of the Sn-3Ag-0.5Cu solder.

Microstructure evolution and hardness of MWCNT-reinforced Sn-5Sb/Cu composite solder joints under different thermal aging conditions

In this work, multi-walled carbon nanotubes (MWCNTs) reinforced Sn-5Sb/Cu composite solder joints were synthesized and the effects of MWCNTs addition on the microstructure evolution and hardness of the Sn-5Sb solder alloy during various thermal aging conditions were investigated. After conducting a thorough microstructural analysis, the SbSn and Cu6Sn5 intermetallic compounds (IMCs) were observed in the β-Sn matrix of the composite solder joints subjected to reflow soldering while the latter was also present at the solder/Cu interface. However, after subjecting the composite solder joints to isothermal aging, the Cu3Sn IMC emerged between the Cu6Sn5 IMC at the solder/Cu interface and the Cu substrate. With the promising properties exhibited by MWCNTs as a reinforcement material, experimental results showed that MWCNTs refined the bulk solder microstructure and inhibited growth of the interfacial IMC layer in the Sn-5Sb-xCNT/Cu samples. In general, the composite sample reinforced with 0.05 wt% MWCNTs showed the least IMC layer thickness and diffusion coefficient in the ranges of 2.6–11.99 μm and 1.07 × 10−14-14.9 × 10−14 cm2/s respectively. Meanwhile, the strengthening mechanism triggered by MWCNTs addition was clearly evident in the MWCNT-reinforced Sn-5Sb/Cu as superior hardness values within a range of 20.6–15.3 HV were registered for the as-soldered and aged composite solder joints with 0.05 wt% MWCNTs reinforcement.

Mechanical characterization of sol-gel alumina-based ceramics with intragranular reinforcement of multiwalled carbon nanotubes

Multiwalled carbon nanotubes (MWCNTs) have been widely considered for mechanical reinforcement of ceramic matrix composites. Nevertheless, the efficiency of this reinforcement strategy is under debate due to fabrication issues, such as a good homogenization or the location of the MWCNTs inside the matrix composite. Regarding this, the intragranular location of the MWCNTs has been deemed a crucial feature for optimizing the reinforcement compared to the typical intergranular placement achieved by conventional procedures. Recently, the sol-gel method has been reconsidered, as it promotes the intragranular placement of the MWCNTs. This work presents the mechanical characterization of these composites synthesized by the sol-gel method, where crack-bridging has been revealed as toughening mechanism. Finally, the conventional use of the bibliographical Young's modulus of pure alumina for the estimation of the fracture toughness is discussed, obtaining significant improvements of the fracture toughness when indentation measurements are treated by considering elastic moduli obtained by nanoindentation.

Vibration analysis of the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow shell panels: An experimental and numerical study

In this study, free and forced vibration analysis of the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow shell panels has been performed. The governing differential equation of motion of the doubly curved laminated composite shallow shell panel is formulated using higher order shear deformation theory with the Lagrangian approach. In a finite element formulation , the mathematical model is derived with a nine-node quadrilateral element considering seven degrees of freedom at each node. The efficiency of the present finite element model (FEM) is demonstrated and compared by validating the results with the available literature, and it is also compared with the experimental measurements of the cylindrical laminated composite shell panel with and without multi-walled carbon nanotube reinforcement. Material properties of the laminated composite structure with and without multi-walled carbon nanotube reinforcements are evaluated through the impulse excitation vibration test in accordance with the ASTM E1876-15. The influence of multi-walled carbon nanotube on the stiffness and structural integrity of the curved laminated composite shallow shell panels is also studied in terms of natural frequencies. Parametric analysis for the multi-walled carbon nanotube reinforced doubly curved laminated composite shallow panel is performed to study the influence of radius of curvature, shell geometry, thickness ratio, aspect ratio, stacking sequence, and the boundary conditions on structural performance. The forced vibration behavior of the curved composite shallow shell panel is studied with the different geometry configuration, and the influence of multi-walled carbon nanotube in the transverse vibration response is also studied. It has been concluded that the rigidity and structural performance of the doubly curved laminated composite shell panels are enhanced with the reinforcement of multi-walled carbon nanotube.

Free vibration analysis of the MWCNT reinforced hybrid laminated composite sandwich beam

Abstract In this study, free vibration investigation of the hybrid laminated composite sandwich beam were performed with and without the reinforcement of multi walled carbon nanotube (MWCNT). MWCNT were dispersed with the epoxy through ultrasonic liquid processor to achieve a good surface contact between the epoxy and MWCNT. Sandwich beam specimens were fabricated with reinforcement of the MWCNT in the laminated composite skin and the structural integrity of the laminated hybrid composite sandwich beam were studied at the distinctive limit conditions. The influence of MWCNT in the sandwich composite structure were studied in the terms of natural frequencies and damping behavior. The infusion of the MWCNT in the laminated composite sandwich structures enhanced the better natural frequencies and damping ratio and this study exposes the impact of the MWCNT on the laminated composite structure

Functionalized Multi-Walled Carbon Nanotubes and Micro Cellulose Reinforced Poly (Vinyl Alcohol) Hybrid Composite Films: Characterization and Reprocessing Performance

The aim of this research paper was to investigate the synergetic effect of micro cellulose and multi-walled carbon nanotubes (MWCNTs) combination on physicochemical, mechanical and reprocessing performance of Poly (Vinyl Alcohol) hybrid composite films. The hybrid composite films production was carried out by the solution casting method, and the reprocessed films were produced using defective (torn, faulty) films from primary production by the same method. The combined use of MWCNTs and micro cellulose improved the hydrophobicity approximately 85% in ratio. After the reprocessing, decreased intensities of the peaks in the FTIR and Raman results confirmed the reduced molecular interaction between all components of the hybrid composite film, moreover, SEM and TEM revealed the negative defects such as agglomeration which caused mechanical strength decrease. The tensile strength of PVA hybrid composite films loaded cellulose/MWCNTs, reached 97 MPa strength value and elongation at break decreased to 33% according to the neat PVA film. The study results revealed that hybridization had a remarkable impact on improving characteristic properties of composite films and reprocessing process might have been compatible with solution casting method.

Comparative Study of Multi-walled Carbon Nanotube Reinforced Natural Rubber Nanocomposite and Multiflex Dynamic Response – 2 Artificial Foot

The desire to restore the quality of life to amputees has been on the front burner in recent years. This study compares the functional properties of a home-grown nanocomposite (NC) and multiflex dynamic response-2 artificial foot (M.DR2). The inherent challenge of ensuring uniform distribution of multi-walled carbon nanotube (MWCNT) in host matrices was addressed by the use of sodium dodecylbenzene sulfonate (C18H29NaO3S). Carbon nanotubes (CNTs) were synthesised via catalytic chemical vapour deposition (CCVD) technique and the NC was produced using an electrically heated hydraulic press. While the initial decomposition temperature (Tonset) showed that the newly developed material with 260.01 °C is more thermally stable than M.DR2 artificial foot with the temperature of 238.17 °C, incorporation of MWCNTs into the unfilled NR matrix proved a significant change in Tonset. MWCNT loading was found to influence the moisture content of the reinforced matrix by about 7% with the NC being 35% more thermally stable than M. DR2 artificial foot. SEM/EDS micrographs indicated complete embedment of MWCNTs in NR matrix, thereby making it more suitable than M. DR2 foot which was inundated with cavities, thereby making it susceptible to early failure. While it took both materials 120 days to attain saturation point NR/MWCNT-3 is 93% more dimensionally stable that M. DR2 and also demonstrated better resistance to wear. The wear rate results revealed that M. DR2 wears faster than NR/MWCNT-3 by approximately 32%. It can, therefore, be concluded from the foregoing that the home-grown material is to be preferred to its foreign counterpart for anthropomorphic prosthetic foot application.

Graphene oxide-assisted multi-walled carbon nanotube reinforcement of the transport properties in cementitious composites

The superior mechanical properties of multi-walled carbon nanotubes (MWCNTs) and prominent dispersibility of graphene oxide (GO) make their hybrid materials have the potential capability for modifying the transport properties of cementitious composites. GO sheets will produce π–π stacking interactions between MWCNTs which not only assist the dispersion but also inhibit the re-agglomeration of the materials. However, as one type of tough two-dimensional materials, GO sheets would cut down the tube length of MWCNTs at the same time, particularly during the ultrasonication process. Thereby, this study characterizes the influence of GO on the dispersion and hydrodynamic size of the hybrid particles using an ultraviolet–visible spectrophotometer and laser particle-size analyzer, respectively. The transport properties of GO/MWCNTs-OPC pastes containing different ratios of hybrid materials were measured, and their microstructure was investigated by mercury intrusion porosimetry and scanning electron microscopy (SEM). The results of this study confirm that 0.02 wt% GO mixed into 0.04 wt% MWCNTs would balance the dispersion-assisted and nanoparticle cutdown effects well and obtain the optimal decrease in resisting water permeability of the materials, about 55.3%, while excessive GO mixing may deteriorate particle-size and influence reinforcing efficiency. Two analytical models and SEM images reveal the mechanism of transport properties reinforcement; GO/MWCNTs not only play a significant role as nucleating sites in assisting the hydration reaction but also form a net-like distribution in the microstructure of cementitious composites. The findings of this study can guide GO/MWCNTs hybrid composite implementation in the future.

Optimization of the Vibration Isolation Performance of an Impact-testing Machine Using Multi-walled Carbon Nanotubes Reinforced Elastomeric Machine Mounts

Optimization of the Vibration Isolation Performance of an Impact-testing Machine Using Multi-walled Carbon Nanotubes Reinforced Elastomeric Machine Mounts