Percentage Of Multi-walled Carbon Nanotubes Research Articles

MWCNT/Al–Bi–NaCl nanocomposites for enhanced H2 generation

H2 generation through hydrolysis of Al-composites has received eclectic attention for on-demand H2 applications such as low-power proton exchange membrane fuel cells. In this line, we prepared Multi-Walled Carbon Nanotubes (MWCNT)/Al–Bi–NaCl nanocomposites and tested them for enhanced H2 generation. These nanocomposites are prepared using high-energy ball milling followed by uni-axial cold compaction. H2 generation by these nanocomposites was tested using tap water at room temperature. An excellent maximum H2 generation rate of 13.33 mLg−1s−1 with an H2 yield of 98% and an induction time of less than 10 s is achieved. Analysis of different observations shows that adding an optimum percentage of MWCNT to the Al–Bi–NaCl composite results in flaky morphology, which facilitates easily accessible water pathways, enhancing the H2 generation rate of the nanocomposites. Also, an enhanced number of MWCNT/Al–Bi microgalvanic cells, optimum utilization of electrical conductivity of MWCNT, and dissolution of NaCl favored the H2 generation.

Characterization and Evaluation of Mechanical Properties of Carbon Nanotube Filler Epoxy Composite

The outstanding mechanical properties of carbon nanotubes (CNT) have made them the focus of extensive investigation. To characterize and study the effects of the different volume fraction of multi walled carbon nanotubes (MWCNTs) on the mechanical properties of the nanocomposites attempted. The purpose of this work is to use experimental techniques to ascertain the mechanical characteristics of the nanocomposite. Tests on mechanical tensile strength were conducted to see how the MWCNT filler content affected the reinforced epoxy nanocomposite. The result of altered percentage of MWCNTs on the mechanical properties of the composites had been inspected. Results showed that 0.2 wt% MWCNT addition has the best effect on the mechanical properties of the matrix.

Thermodynamic analysis of EMHD ternary nanofluid flow with shape factor effects over a shrinking sheet: A non-Fourier heat flux model

The investigation of the flow characteristics of ternary hybrid nanofluids through a contracting sheet has considerable importance due to its potential for achieving exceptionally high rates of heat transfer. The ternary hybrid nanofluid then absorbs heat from the surface and carries it away. The objective of this study is to analyze the influence of couple stress and activation energy parameters on the flow of a ternary hybrid nanofluid ( H 2 O + MWCNT + ZnO + Al 2 O 3 ) through a contracting sheet with electric forces and convective boundary conditions. The heat flux model created by Cattaneo and Christov is utilized to examine the mechanism of heat transmission. The equations necessary to depict the problem have been transformed into a system, which has subsequently been resolved using the bvp4c solver (MATLAB built-in function). It is found that there is a rise in the Bejan number with the increase in the couple stress parameter. An increase in the volume percentage of multi-walled carbon nanotubes ( ϕ MW ) is observed to result in an augmentation of entropy generation . It has been observed that there is a fall in the friction factor when the couple stress parameter rises and at 0 ≤ Ed ≤ 0.6 , (electric field parameter), the friction factor is seen to rise at a rate of 0.638797 (Platelet) and (0.638784). A positive correlation is observed between the thermal relaxation parameter ( ϒ ) and fluid temperature, indicating that a rise in the former leads to an increase in the latter. It is discovered that, when 0 ≤ ϒ ≤ 0.3 , the Nusselt number rises by 0.022587 (Platelet) and 0.022275 (Cylinder). There is a negative correlation between the upsurge in the activation energy parameter ( Eg ) and the corresponding rise in the Sherwood number. At 0 ≤ Eg ≤ 3 , the Sherwood number is seen to decline at a rate of 0.0321 (Platelet) and 0.03208 (Cylinder).

Investigation on the effect of multiwalled carbon nanotubes in carbon fiber‐reinforced epoxy composites manufactured using vacuum infusion process and hand layup process followed by vacuum bagging

AbstractEpoxy/carbon fiber (CF) composites are widely used for structural applications owing to their exceptional mechanical and physical characteristics. The main aim of this work is to individually analyze the impact of multiwalled carbon nanotubes (MWCNTs) as nanofillers in epoxy/MWCNTs/CF composites prepared by vacuum infusion process (VIP) and hand layup followed by vacuum bagging technique (HLVB). Optimal Manufacturing Strategies were followed at various stages of manufacturing which include the selection of effective dispersion technique for MWCNTs, identification of optimal weight percentage of MWCNTs in epoxy/MWCNTs nanocomposites and preparation of epoxy/MWCNTs/CF composites. For HLVB samples, tensile and flexural strengths increased from 337.5 to 475 MPa and 615.40 to 677.09 MPa. For VIP samples tensile and flexural strengths increased from 371 to 521 MPa and 714.19 to 769.02 MPa. Thermogravimetric analysis (TGA) indicated improvement in the thermal stability of epoxy with the incorporation of MWCNTs/CF and improved weight percentage retention of 84.7% at 375°C. Fracture analysis of the epoxy/MWCNTs/CF composites prepared using VIP were analyzed by FE‐SEM and revealed that constant fiber rupture caused by better interface and improved bridging mechanism eventually led to enhanced mechanical performance. The predominant immediate fracture mechanism of MWCNTs also indicated this improved interfacial interaction.Highlights Pull‐out fracture mechanism was predominantly seen in high viscous epoxy/MWCNTs composites Immediate fracture mechanism of MWCNTs were predominant in low viscous epoxy/MWCNTs sample Constant fiber rupture of VIP samples indicated improved fiber matrix interface Incorporation of MWCNTs showed improved weight percentage retention 0.5 wt% MWCNTs incorporated VIP epoxy/CF composites showed improved performance

Ultrasonic-assisted of TiO2-MWCNT nanocomposite with advanced photocatalytic efficiency for elimination of dye pollutions

Nanocomposites of titanium dioxide (TiO2) and multi-wall carbon nanotubes (MWCNTs) were successfully synthesized (TiO2-MWCNTs) from MWCNTs and titanium tetrachloride (TiCl4) as starting precursors using ultrasonic-assisted technique. The impact of the different weight percentages of MWCNTs (1, 3, 5, and 7 wt%) on TiO2 optical, structural, and morphological properties were investigated. Subsequently, the photocatalytic activity was assessed by organic dyes degradation such as methylene Blue (MB) and rhodamine B (RhB) under ultraviolet (UV) light exposure. The characterization of synthesized materials demonstrated the anatase phase formation in both pure TiO2 and the TiO2-MWCNTs nanocomposite, according to X-ray diffraction analysis. The morphology analysis of TiO2-MWCNTs nanocomposites using FESEM and TEM confirmed the uniform dispersion of MWCNTs with an exterior diameter of 12–16 nm within the TiO2 matrix. The BET measurement of the sample's specific surface areas identified that the MWCNTs addition resulted in the increase of surface area from 76.34 to 194.35 m2 g−1 for pure TiO2 and TiO2/7 wt% MWCNTs, respectively. Furthermore, TiO2/7 wt% MWCNTs nanocomposite had lower optical bandgap energy and higher photocatalytic performance as compared to the pure TiO2. The photodegradation efficiency of TiO2/7 wt% MWCNTs nanocomposite increased from 63.63 % to 92.36 % for MB and 71.56 % to 94.13 % for RhB compared to pure TiO2, after 60 min UV light exposure.

Super plasticizer assisted bath ultra sonication for dispersion of multi walled carbon nanotubes in cement composites

This paper presents the observations and findings from an experimental study for dispersion of multiwalled carbon nanotubes (MWCNTs) by bath ultra-sonication in the presence of polycarboxylate ether (PCE) based superplasticizer. Commercial brand of superplasticizer (SP) compatible with cement was adopted for exploring its usage as surfactant during aqueous dispersion of MWCNTs. Cement composite pastes were evaluated for variation in compressive strength and fresh property for a fixed addition percentage of MWCNT. Aqueous dispersion of MWCNTs for incorporation to cement pastes was prepared considering three different sonication process variables; time period of sonication, SP to MWCNT dosage during sonication and temperature of sonication medium. A total of 168 experimental variations were evaluated for compressive strength of resulting cement–carbon nanotubes composite pastes at 7 days age to arrive at an optimal process of bath ultra-sonication with governing variables. Results showed that a sonication time period in the range of 4–5 hours with an SP to MWCNT ratio of 2.5–3 was necessary for satisfactory dispersion of MWCNTs over different temperature ranges of sonication bath medium. Further, the temperature of sonication medium in the range of 35–40°C during aqueous dispersion of MWCNTs was observed to induce noticeable enhancement in strength of composite system indicating improvement in dispersion within an optimal range of sonication medium temperature. Microscopic observations for optimal process variables of dispersion during bath ultra sonication showed evidence of physical changes in MWCNTs from an agglomerated state of particles to separated state.

High performance of asymmetric coin cells designed using optimized weight percentage of multiwalled carbon nanotubes in Ni/Co-MOFs nanocomposites

• 20% of F-MWCNTs in Ni/Co-MOF was better than other weight % of F-MWCNTs. • Ni/Co-MOF/20% F-MWCNTs exhibited a high Cs of 1779 F/g at 2 mV/s & 890 F/g at 2.5 A/g. • The coin cell with Ni/Co-MOF/20% F-MWCNTs//AC offered ED-56 Wh/kg & PD-11 kW/kg. • Six-coin cells in series were used to power three red coloured LEDs for 3 minutes. Nanocomposites (NC-X) of Ni/Co-MOFs with varying weight % of functionalized multiwalled carbon nanotubes (F-MWCNTs) were synthesized by solvothermal method. Physicochemical properties of NC-X were analyzed by different analytical techniques. Further, electrochemical studies were made to comprehend the effect of weight % of F-MWCNTs in the nanocomposites for high-performance supercapacitors. 20 weight % of F-MWCNTs in the nanocomposite exhibited higher supercapacitance performance (890 F/g at 2.5 A/g) than other nanocomposites. The fabricated asymmetric coin cell (ASC) offered high energy and power densities of 56.25 Wh/kg and 11.9 kW/kg respectively with 20,000 cycle stability at 25 A/g (1 M KOH). The ASC also retained 72% capacitance with 100% coulombic efficiency at 20,000 th cycle. Six ASC of each cell with operating potential window of 1.8 V were utilized in powering three red light emitting diodes (LEDs-12 V) connected in series. Thus, demonstrating the practical application of ASCs to power LEDs for 3 minutes.

A comparative study on thermophysical properties of functionalized and non-functionalized Multi-Walled Carbon Nano Tubes (MWCNTs) enhanced salt hydrate phase change material

Thermal energy storage (TES) system is one of the best options for harvesting, storing, and saving energy for long-term or short-term use of a modern energy production system. The nano-enhanced phase change materials (NePCM) are a new type of phase change materials (PCM) formed by suspended nano-sized particles in base PCM to improve the thermophysical properties of the base PCM. The major challenge in nanoparticle dispersion in PCM, especially for solar energy applications, is its poor thermal conductivity and light transmission capability. Present research aims to address the thermal conductivity and light transmission capability issues by dispersing pristine multi-walled carbon nanotube (MWCNT) and functionalized multi-walled carbon nanotube (FMWCNT) particles in various weight concentrations (0.1, 0.3, 0.7, and 1.0%) into the salt hydrate PCM. A two-step technique was implemented to develop the NePCM for various weight percentage of MWCNT and FMWCNT. The Fourier transform infrared (FTIR) spectrum shows the MWCNT and FMWCNT nano-sized particles physically mixed well in salt hydrate PCM and without disturbing the chemical properties. The thermal conductivity of developed composites at 0.7 wt% MWCNT/S50 (S50M-0.7) and 0.7 wt% FMWCNT/S50 (S50F-0.7) are 0.78 W/mK, and 0.92 W/mK, respectively. The Differential Scanning Calorimetry (DSC) results revealed that the maximum improvement in latent heat by 14.66% and 31.17% for 0.1 wt% MWCNT/S50 (S50M-0.1) and 0.3 wt% FMWCNT/S50 (S50F-0.3) respectively. Light transmittance of S50M-0.7 and S50F-0.7 reduced to 92% and 93.49% than pure salt hydrate PCM. It exhibits the reduction in transmittance, greater improvement in solar spectrum absorption, and excellent photothermal conversion. • Study on Functionalized and non-Functionalized MWCNT enhanced PCM. • Comparative thermal performance of MWCNT and FMWCNT enhanced salt hydrate PCM. • A remarkable enhancement in thermal conductivity by 100% for S50F-0.7 • A substantial reduction in light transmittance by 93.49% for S50F-0.7 than base PCM.

Application of Molecularly Imprinted Poly-Itaconic/Multiwalled Carbon Nanotubes for Selective and Sensitive Electrochemical Detection of Linagliptin

In this work, we report the first molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of the antidiabetic drug Linagliptin (LNG) in pure sample, tablets, and spiked human urine and serum samples. Using a graphite electrode, differential pulse voltammetry (DPV) was applied to study the electrochemical behavior of LNG in a Britton Robinson (BR) universal buffer of pH 8 with Ag/AgCl electrode and Pt wire. The sensor is based on the modification of the traditional carbon paste sensor with Itaconic acid (IA) as monomer, which cross-linked using ethylene glycol dimethacrylate (EGDMA) and multiwalled carbon nanotubes (MWCNTs) as a modifier. The different factors were optimized, such as ratio of MIP components, percentage of multiwalled carbon nanotubes (MWCNT), pH, accumulation time, accumulation potential and scan rate. The proposed sensor was characterized morphologically using: Scanning electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) and electrochemically applying electrochemical impedance spectroscopy (EIS)and cyclic voltammetry (CV). DPV was applied to obtain the calibration curve and optimization of different factors, the proposed sensor shows a wide linear range of 1 × 10−12M (0.47 ng l−1) to 1 × 10−7M (47.26 μg l−1) and limit of detection (LOD)1 × 10−13M (0.05 ng l−1) while the limit of quantification (LOQ)was found to be 3.3 × 10−13M (0.16 ng l−1) in addition to good reproducibility and selectivity.

Durability characteristics and mechanical properties of multi-walled carbon nanotubes reinforced concrete, a case study: Caspian seawater curing condition

Using multi-walled carbon nanotubes (MWCNTs) as an additive in a concrete mixture with an amount of 0.05 to 0.2% wt. of cement weight with a constant W/C ratio using local materials was investigated in this research. Specimens were cured in water and the Caspian Seawater curing conditions, and compressive strength tests were performed on samples up to 365 days of age. Also, flexural strength, water absorption after immersion, water permeability and porosity tests and, SEM studying were performed on specimens. Results showed that increasing the amount of MWCNTs up to 0.2% of cement weight improved the workability, compressive, and flexural strength of concrete mixtures. The addition of MWCNTs caused a mild improvement in concrete specimens’ strength which were cured in Caspian Seawater compared with control concrete. In the water absorption and water permeability tests, it was seen that a lower percentage of MWCNTs decreased the results, but more amount of MWCNTs may affect vice versa. In porosity studying, it was seen that more amount of MWCNTs may cause smaller pore sizes, however may increase the porosity and CNTs’ agglomeration in concrete.

Response parameters modeling of abrasive jet machined composite using artificial neural network

Machining of polymer based nanocomposite is very challenging. Though these materials possess unique properties and developed for specific applications. Therefore analysis of material processing performance of a particular machining process is become essential. Performance of a process can be understood by establish a mathematical relationship between input and output parameters. This empirical relationship can be useful for election of significant variable factors. Once these factors elected then better quality characteristics can be obtained at economical cost. In present study mathematical models for surface roughness and kerf taper of abrasive jet machined nanocomposite are developed using artificial neural network. To check the accuracy of developed models the predicted values of consider quality characteristics are compared with previous published experimental values. Input parameters jet pressure, traverse rate, weight percentage of multi-walled carbon nanotubes and stand of distance for abrasive jet machining of carbon fiber reinforced polymer composite are considered. Average percentage prediction error found less than 5% that shows predicted values from developed models are accurate.

EVALUATION OF A HYBRID BIOCOMPOSITE OF HA/HDPE REINFORCED WITH MULTI-WALLED CARBON NANOTUBES (MWCNTs) AS A BONE-SUBSTITUTE MATERIAL

In this investigation, multi-wall carbon nanotubes (MWCNT) with various percentages (0.6%, 1%, 1.4%, 2%) were combined into ​and High-density polyethylene HDPE (60) wt. % and hydroxyapatite (40) wt. % to form biocomposite using hot-press techniques. The surface topography by AFM images illustrates differences in the roughness of the sample's surface with different adding percentages of MWCNT. The DSC technique exhibits the effect of adding MWCNT in different percentages with the degree of crystallinity, which its effect on mechanical properties for samples. The in vitro bioactivity was investigated by immersion the samples in Ringer's solution as simulated body fluid (SBF) at (0, 3, 6, 9, 12) days (after immersing). The FE-SEM and EDx image explained the apatite layers formation on the sample's surface after 3 days immersed in Ringer solution. Based on XRD Technique, after immersion days in the Ringer solution, the crystallographic structure of hydroxyapatite is formed, forming the monetite. ​The enhancement of bioactivity has been shown during the incorporation of MWCNT into HA/HDPE composite. These results exhibited excellent indications of biocompatibility properties with the possibility of making promising biomaterials for making bone substitute applications.

Mechanical Properties of novel hardened cement paste reinforced with Multi-Walled Carbon Nano-Tubes (MWCNTs) and Glass Fibers Nano material

To improve the mechanical and durability properties of ordinary Portland cement (OPC) mortar and paste, the incorporation of multi walled Carbon nanotubes (MWCNTs) and their dispersion procedures, functionalization, and ultra sonication have been intensively implemented. Most of the studies showed significant enhancements in the mechanical properties of OPC mortar or paste; however, others showed impairments. The recent studies regarding the implementation of MWCNTs and Glass Fibres on the mechanical properties of OPC paste and mortar were reviewed and these properties include compressive, tensile, flexural strengths, and elastic modulus. A statistical study was conducted to evaluate the mechanical properties of concrete by dispersion of MWCNT’s and Glass Fibres in the cement paste. In these composites, the percentage of MWCNTs was fixed at 0.75% by weight of cement, while the percentage of Glass Fibers was fixed at 0.25% by weight of cement. The samples were cured in tap water for 28 days at 25 + 2?C.Composite specimens were tested for compression and flexure in order to evaluate their mechanical properties such as compressive strength, flexural strength, toughness and ductility and compared with the results of plain cement control beams. The maximum deflection was found to be 0.5mm with a maximum load of 500N. The flexural strength was observed to be 1250.50 N/mm2 as per ASTM D 790 which is 20% more than the flexural strength obtained with Plain Cement+MWCNT’s and 60 to 70% more than that obtained with Plain Cement + Glass Fibres. The flexural modulus as per deflection criteria is 535.94 N/mm2 which is 10 to 20% more than that obtained of Plain Cement+MWCNT’s and Plain Cement+ Glass Fibres. The compressive strength of Plain Cement+0.75% MWCNT’s+0.25% Glass fibres was found to be 65 N/mm2 which is greater than Plain cement and Plain cement+MWCNT’s. Surface morphology by Scanning Electron microscopy of the specimens infers the clustering of glass fibres and demonstr

Synthesis of composite material of cobalt oxide (Co3O4) with hydroxide functionalized multi-walled carbon nanotubes (MWCNTs) for electrochemical determination of uric acid

The gout is mainly found due to accumulation of uric acid crystals into the joints which produces the inflammatory symptoms. Thus, it is highly demanded to detect uric acid from our body. Herein, we prepare a composite material of cobalt oxide (Co3O4) with hydroxide functionalized multi-walled carbon nanotubes (MWCNTs) by hydrothermal method. The composite material is used for the modification of glassy carbon electrode (GCE) and investigated for the electrochemical determination of uric acid (UA). The analytical techniques such as scanning electron microscopy (SEM), powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Fourier Infra-red spectroscopy (FTIR) are used to characterize the composite material. The Co3O4 exhibits a dendrite morphology and very well chemically coupled with MWCNTs. The elemental analysis confirms the presence of cobalt (Co), oxygen (O) and carbon (C) as main constituent of the composite material. The Co3O4 exhibitsa cubic unit cell crystallography in the composite system. The FTIR study reveals the characteristic bands of Co–O bands in the composite material. The cyclic voltammetry isused to study the electrochemical properties of prepared materials. The composite sample with highest percentage of MWCNTs shows an excellent electrochemical activity towards the oxidation of uric acid in phosphate buffer solution pH 7.3. The enzyme free uric acid sensor possesses a linear range of 0.1 mM to 3 mM with a quantified limit of detection of 0.005 ± 0.0023 mM. The modified electrode is stable, selective, and very sensitive towards uric acid, therefore it may be used for the monitoring of uric acid from clinical samples. The proposed composite material can be of great interest for energy and biomedical fields.

Studies on the influence of weight percentage of multiwalled carbon nanotubes in Mn/Ni/Co nanocomposites for hybrid supercapacitors

In this work, four composites of varied percentage of multiwalled carbon nanotubes (MWCNTs) with Mn, Ni, and Co oxide nanoparticles (TMO) were prepared by hydrothermal process and abbreviated as MNC-1, MNC-2, MNC-3 and MNC-4. The prepared materials were characterized for their physico-chemical properties by Powder XRD, SEM, TEM, BET, XPS, FT-IR and Raman analytical techniques. The electrochemical properties of the composites were evaluated in a three-electrode system incorporating the composite as the working electrode. Among the nanocomposites investigated, the MNC-3 sample with the TMO and MWCNTs ratio of 1: 0.25 showed lowest surface area, pore volume and pore diameter. Further, this sample exhibited highest specific capacitance of 985 F/g at 2 mV/s by cyclic voltammetry in 1 M KOH solution. This material when checked for its stability at high current density of 15 A/g for 5,000 cycles, showed 83% capacitance retention which subsequently changed to 70% after 10,000 cycles. An asymmetric supercapacitor device was designed using MNC-3 as the positive electrode and a commercial activated carbon as negative electrode. The device exhibited significant specific capacitance, energy density and power density values of 58 F/g, 17 Wh/kg, and 1768 W/kg, respectively. A life cycle test conducted for the fabricated device at a current density of 15 A/g showed capacitance retention of 78% even after 10,000 cycles. The practical application of the device was checked and demonstrated by powering two red LEDs connected in series for 12 mins.

Multi-walled carbon nano-tubes for enhancing the performance of cementitious composites

Due to exceptional properties, multi-walled carbon nano-tubes (MWCNTs) are designated as a promising reinforcing material for the nano-modified cementitious composites. The performance of cementitious composites with MWCNTs on the mechanical, durability, and microstructure properties was investigated in this study. The MWCNTs were effectively dispersed by the sonication method using high-frequency ultrasonic waves. The flexural strength, compressive strength, density, porosity, and stress-strain curves of cementitious composites reinforced with different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5 wt%) of MWCNTs were studied. The enhanced flexural and compressive strength demonstrates the exceptional reinforcing behaviour of the MWCNTs. Additionally, density outcome indicates that as the percentage of MWCNTs in the matrix increases, density increases, and the optimum content was obtained as 0.3 wt%. The pores of cementitious composites can be reduced by adding carbon nano-tubes, which was perceived through a microstructural study using SEM micrographs. Study outcomes establish that in addition to the advantages provided by the nano-tube reinforcement in augmenting strength, nano-tubes can also help in reducing the porosity of the composites. The effectiveness of this promising nanomaterial related to its field application is also highlighted.

Mechanical, corrosion and cavitation erosion properties of LM 9 grade aluminium – multi-walled carbon nanotubes composites

ABSTRACT This paper is intended to study mechanical, corrosion and cavitation erosion properties of aluminium metal matrix composites with Multiwalled carbon nanotubes (MWCNTs) as reinforcement. Multi-walled carbon nanotubes in different weight percentages (1, 2 and 3%) are reinforced in Light metal 9 (LM 9) aluminium alloy using the ultrasonic stir casting method. Hardness, pitting corrosion potential and erosion resistance are evaluated to assess the influence of different weight percentages of MWCNTs as reinforcements in LM 9 alloy. The results indicate that Aluminium – MWCNTs composites possess an improved hardness of up to 150 % compared to base LM 9 alloy. The pitting corrosion resistance of composites was found to be excellent with minimum corrosion damage to the composite specimen. Cavitation erosion test performed as per ASTM G32 indicates a decrease in erosion wear for composites reinforced with MWCNTs compared to base material LM 9. The property improvement of the LM 9 – MWCNT composite under dynamic conditions is verified using SEM micrographs. The effect of weight percentage of MWCNTs found to be significant in the enhancement of properties. There are 16 % and 30 % reductions respectively in pitting corrosion potential and erosive wear respectively for composite with 3 % MWCNTs.

Experimental investigation on heat transfer behavior of the novel ternary eutectic PCM embedded with MWCNT for thermal energy storage systems

In this paper, the variation of thermophysical properties such as the thermal conductivity, thermal energy storage capacity, viscosity, and phase change temperature of the novel ternary eutectic phase change material (PCM) with respect to multi-walled carbon nanotubes (MWCNTs) concentration are investigated. The novel ternary eutectic PCM was formed by the permutation of oleic acid, isopropyl palmitate, butyl stearate in a eutectic mole fraction of 0.44–0.33–0.23. The heat transfer analysis of the materials encapsulated in spherical ball was experimentally investigated. The results concluded that the ternary eutectic PCM with 0.10 mass percentage of MWCNT enhances the heat transfer rate by 34.45% with respect to the pure PCM. Furthermore, the thermal conductivity of the MWCNT dispersed ternary eutectic PCM shows an increasing trend and reaches the maximum enhancement of 67.28% for 0.10 mass percentage of MWCNT concentration. The crystallinity decrement of the composite PCM was increased linearly from 0.19 to 3.2% for the increasing MWCNT concentration along with the convergence of melting and solidification enthalpy at the maximum dispersion of MWCNT concentration. New correlations governing the variation of thermal conductivity, viscosity and thermal expandability of the ternary eutectic PCM with respect to MWCNT concentrations have also been developed and presented in this study. The novel ternary eutectic PCM with 0.10 mass percentage of MWCNT with good thermal reliability after 500 thermal cycles and compatibility with the spherical encapsulated high-density polyethylene ball could be an eminent candidate for low-temperature cold storage applications.

Evaluation of the rheological behavior, hydration process, and mechanical strength of Portland cement pastes produced with carbon nanotubes synthesized directly on clinker

Multi-walled carbon nanotubes (MWCNTs) have been incorporated in cementitious composites and important results in terms of rheological and mechanical performance have been obtained. Despite the current MWCNT dispersion procedures found in the literature, MWCNT synthesized directly on clinker is an alternative route to employ this nanomaterial in cementitious composites. It is also much more compatible with the procedures used by the construction industry. Based on this scenario, this study presents results in terms of rheological behavior, hydration process and mechanical strength of cement pastes (with a water/cement ratio of 0.4), produced with MWCNTs synthesized directly on clinker. The percentage of MWCNTs was equal to 0.15 and 0.30% with respect to cement content (bwoc). A reference paste without MWCNTs was also produced for comparison. In terms of the rheological behavior, the cement pastes with MWCNTs showed adequate performance for the application. It was also verified that MWCNTs promoted an increase in the cement hydration rate, reducing the initial setting time and changing the hydration period. This was most evident when the MWCNT rate was increased from 0.15 to 0.30% bwoc. With respect to compressive and tensile strength, the pastes with MWCNTs showed gains of 28% and 43% respectively at the age of 28 days for the 0.15% carbon nanotube content.

Effect of Ultrasonic Stir Casting Technique on Mechanical and Tribological Properties of Aluminium–Multi-walled Carbon Nanotube Nanocomposites

This paper studies the enhancement of the mechanical and tribological properties of multi-walled carbon nanotubes (MWCNT)-reinforced aluminium nanocomposites prepared by ultra-sonication-assisted stir casting method. The investigations were made to assess the effect of MWCNT weight percentage on the property enhancement of nanocomposites. MWCNTs in 1, 2 and 3% weight is added to LM 9 grade aluminium and processed in a stir casting machine with an ultrasonic probe. The ultra-sonication during casting resulted in a better dispersion of MWCNTs in the base materials. The results indicate a significant improvement in the hardness of the nanocomposite. The wear rate and coefficient of friction of Aluminium–MWCNTs composite have notably reduced during the test on a pin on disk tribometer compared to LM 9 aluminium base material. The percentage of MWCNTs is found to be a significant factor, and there is a progressive improvement in the properties with 3 wt% of MWCNTs–Aluminium composite giving the best performance.