Nanotube Content Research Articles

Design of PDMS/CNT flexible pressure sensor based on double structure with the regulation of electrical properties

Introducing microstructure on the surface or porous structure inside of dielectric layer can improve the sensitivity and monitoring range of the flexible pressure sensor. However, developing pressure sensors with high sensitivity in the high-pressure range is challenging because of the trade-off between sensitivity and linearity of pressure. Here, we report a design approach based on the collaboration of double structure and electrical characteristics that can improve sensor sensitivity at high pressure. The surface microstructural and internal porous structure of the dielectric layer provide a more comprehensive deformation range for the sensor from a mechanical perspective. The effects of the conductive carbon nanotube (CNT) content between two structures on the overall electromechanical characteristics of the sensor were studied. This collaborative (structure and component) design can effectively increase the monitoring range of the sensor and accomplish “gear shifting” of the sensitivity by the non-uniform distribution of CNT in the structure. The optimized capacitive pressure sensor exhibits outstanding sensitivity over a wide monitoring range (1.17 kPa−1 in the 0−100 kPa, 0.49 kPa−1 in the 100−350 kPa, and 0.23 kPa−1 in the 350−1000 kPa), and fast response capability (30 ms). The pressure sensor has excellent integrated sensing performance in rubber wheels' static/dynamic pressure monitoring, demonstrating application potential in high-pressure fields.

Liquid crystalline substances doped with carbon nanotubes as a sensitive medium of the CO2 sensor

The creation of highly sensitive optical CO2 sensors in air is an urgent problem, as it allows monitoring of the content of CO2 both indoors and in ambient air, where its level is usually 600…1000 ppm. As a sensitive element of the CO2 sensor, it is proposed to use a liquid crystal substance (cholesteric-nematic mixture based on 5CB with cholesteric impurities), supplemented with multi-layered carbon nanotubes. The spectral characteristics of the liquid crystal mixture in the range of 400…600 nm were studied. The content of carbon nanotubes ranged from 0.1 to 0.5 wt.%. It was established that with an increase in concentration in the range of 10…100 mg/m3, the transmission minimum shifts to the long-wave region of the spectrum. The maximum spectral sensitivity in this range is 6 nm ⁄ mg ⁄ m3. The researched material can be used as a sensitive element of an optical CO2 sensor. Further research should be conducted in the direction of investigating the interaction of such a composite with other gases, as well as finding opportunities to improve the properties of the composite. Perhaps the use of multi-walled carbon nanotubes.

Electromagnetic interference shielding performance of Ag/multi-walled carbon nanotubes-poly(methyl methacrylate) composites

An efficient strategy for synthesizing Ag/multi-walled carbon nanotubes-poly(methyl methacrylate) (Ag/MWCNT-PMMA) composites has been proposed. The synthesis concept is based on the modification of oxidized MWCNT with Ag nanoparticles and subsequent distribution of the obtained Ag/MWCNT-Ox hybrids in a PMMA matrix. Herein, Ag/MWCNT-Ox hybrids with various size and content of Ag nanoparticles serve as a tool for tuning the electrical conductivity of the two series of Ag/MWCNT-PMMA composites with MWCNT-Ox content before (4 wt%) and after (10 wt%) the percolation threshold. Adding 0.2 wt% of Ag to the first composite series with nanotubes content of 4 wt% leads to a decrease in the percolation threshold in a three-component system. In the case of the second composite series, the introduction of Ag up to 1 wt% leads to a monotonic increase in the conductivity within one order of magnitude. Ag/MWCNT-PMMA demonstrates high shielding efficiency for incident radiation in the frequency range of 26–37 GHz, most of which is absorbed due to the conductive nature of the material. The improved electromagnetic properties of the Ag/MWCNT-PMMA composites are explained by the uniform distribution of fillers in the polymer, which ensures the formation of a 3D conducting network inside the composite, and by the synergistic interaction between MWCNT and Ag. Thus, Ag/MWCNT-PMMA composites have broad application prospects in the field of electromagnetic compatibility.

Influence of carbon nanotubes on the plasma electrolytic oxidation process of aluminum under “soft” sparking conditions

Plasma electrolytic oxidation of aluminum (PEO) was performed with dispersed multi-walled carbon nanotubes (MWCNTs) into the electrolyte. The effect of the carbon nanotubes concentration, as well as that of the electrical processing conditions, on the PEO process was investigated. From the point of view of the electrical response of the process, results show that the “soft” sparking regime appears earlier in presence of MWCNTs. The process time at which the transition to the “soft” regime occurs decreases linearly with the increase in the MWCNTs concentration. Over a concentration threshold, depending on the applied pulse bipolar current waveform, the PEO process is inhibited. The dispersion of MWCNTs in the electrolyte results in thicker but more porous alumina layers. More specifically, the proportion of the α-alumina phase relative to the γ-alumina phase decreases with the increase in the MWCNTs concentration. Results are explained by considering the increased coating growth kinetics and lower heat accumulation from MWCNTs addition. Finally, the present study gives new insights into the right management of the PEO process under “soft” sparking regime with dispersed carbon-based nanoparticles in the electrolyte.

The effect of novel advanced method on the properties of novolac hybrid nanocomposites reinforced with carbon nanotube and glass fiber

AbstractIn this study, the effects of ball milling (BM) technique and carbon nanotube (CNT) content on the thermal and mechanical properties of hybrid reinforced composites were investigated. The composites were prepared using glass fiber (GF), novolac resin (No), and CNTs with different wt% (1, 2, and, 4). Various milling times were used to optimize the entanglement/agglomeration of CNTs in the polymer matrix and subsequently enhance the final thermal and mechanical properties. Through precise investigations, it was found that the nanocomposite with 2 wt% CNT reinforcement, subjected to 2 h of BM, exhibited remarkable enhancements in key properties. The tensile strength was significantly improved to 45.6 MPa, while the elastic modulus reached 3.419 GPa. Hardness was measured at 96 HRM, and thermal conductivity was enhanced to 0.463 W/mK. Moreover, this sample demonstrated a weight loss that was 43.65% lower compared to the sample reinforced with 1 wt% CNT and subjected to 1 h of BM. Overall, this study highlights the importance of optimizing the milling time and CNT content in the preparation of polymer nanocomposites, and it provides valuable insights for the development of advanced materials with superior performance in various applications.

Combustion and emissions characteristics of a diesel engine fuelled with diesel fuel and different concentrations of amino-functionalized multi-walled carbon nanotube

Nanoparticles have recently been used as fuel additives to enhance diesel engine performance and exhaust gas emissions. Amino-functionalized multiwalled carbon nannotubes (NH2-MWCNTs) are catalysts that can be applied in diesel engines because of their promising properties. This study conducted an experimental investigation to determine the impacts of adding NH2-MWCNTs to diesel fuel using a single-cylinder CI engine running at a constant speed (1500 rpm) and various loads. The NH2-MWCNTs were added to diesel fuel at four concentrations of 25, 50, 75, and 100 ppm. Also, the same doses of pristine multiwalled carbon nanotubes (MWCNTs) were added to diesel to be used as a reference for NH2-MWCNTs. Most NH2-MWCNTs blends were preferred in combustion characteristics, engine performance, and exhaust emissions compared to diesel and MWCNTs blends. Thus, there was a considerable increase in cylinder pressure and heat release rate compared to pure diesel. Also, the brake thermal efficiency was increased, and the brake-specific fuel consumption was decreased compared to diesel. Most NH2-MWCNTs combinations appeared to decrease NOx, soot, and CO levels significantly. The NH2-MWCNTs blends are generally favored over the pristine MWCNTs blends in reducing exhaust emissions.

The influence of single and multi-carbon nanotubes as additives in diesel-biodiesel fuel blends on diesel engine combustion characteristics, performance, and emissions

The introduction of biodiesel as a suitable alternative fuel has been made in response to the issues with fossil fuels, such as their overconsumption, threats to the environment, and rising costs. Researchers have therefore been interested in locating new sources for the manufacture of biodiesel. Additionally, due to their exceptional qualities, carbon nanotubes have attracted attention in other fields. The current study aims to examine the impact of single and multi-carbon nanotubes (SCNT and MCNT) as an additive at 25, 50, and 75 ppm on diesel engine combustion characteristics, performance, and emissions. The base fuel is a blend of pure diesel and biodiesel (B5, B10, B15, and B20). Nanotubes were created, TEM and XRD analyzed, and ultrasonically blended with diesel + biodiesel blends at 25, 50, and 75 ppm. When MCNT and SCNT are added to fuel blends, peak pressure rise and heat release rates increase by up to 18.88% and 19.65%, respectively. Increased carbon nanotube content in fuel 10 blends enhanced brake power, torque and BTE by 4.7–4.8%, 3.1–3.2% and 0.2–5.2%, respectively, while lowering brake-specific fuel consumption by 6.5–6.9%. HC, CO2, and NO x emissions were also higher by 0.2–5.2%, 0.5–8.7% and 0.3–6.8%, respectively.

Effect of multi-walled carbon nanotubes on the microstructure and properties of Sn-58Bi solder alloys

The influence of multi-walled carbon nanotube (MWCNT) content on the melting properties, wettability, microstructure, and intermetallic compounds (IMCs) of Sn-58Bi-xMWCNT (x = 0, 0.01, 0.02, 0.03, 0.05, and 0.10 wt.%) and the effects of MWCNT on the tensile strength of Cu/Sn-58Bi-xMWCNT/Cu solder joint were analyzed. The results show that MWCNT addition at a small trace amount into Sn-58Bi solder could increase the spreading area of Sn-58Bi solder, refine the solder matrix microstructure, inhibit the growth of interfacial IMCs, and significantly improve the tensile strength of Sn-58Bi solder joints. However, the melting point and melting range remained the same or slightly changed. The wettability of Sn-58Bi alloys increased first and then decreased with the addition of MWCNT. The spreading area and the tensile strength of solder joint were the maximum when the MWCNT content was 0.01 wt.%, and they were 42.23 mm2 and 50.07 MPa, respectively. The reason may be related to the improved microstructure of solder alloys and the morphology of IMCs due to MWCNT addition at trace level.

Printable Poly(N-acryloyl glycinamide) Nanocomposite Hydrogel Formulations

Printable synthetic polymer formulations leading to hydrogels with high strengths, swelling resistance, and bioactivities are required to control the mechanical and functional characteristics of biological scaffolds. Here, we present nanocomposite hydrogels prepared with the upper critical solution (UCST)-type polymer ink poly(N-acryloyl glycinamide) (PNAGA) and different concentrations of carbon nanotubes (CNTs). Nanofiller CNTs are recommended for increasing the bioactivities of hydrogel scaffolds. Printing methods were established in which the CNTs were included before and after the fabrication of the ink. The methods were compared to each other and their temperatures and shear-thinning properties were determined from the rheologies. A self-thickening method was utilized for 3D printing of nanocomposite constructs, and the printabilities varied with the CNT content and preparation method. After photopolymerization of the printed constructs, the nanocomposite hydrogel exhibited a slightly higher mechanical strength (15,500 Pa, Emod = 0.697 ± 0.222 MPa), great elasticity (elongation ~500%) and an electrical conductivity (5.2‧10−4 ± 1.5‧10−4 S‧m−1) comparable to that of the neat PNAGA hydrogel. Since high-strength constructs can be 3D printed with good resolution and low cytotoxicity, these nanocomposite hydrogel scaffolds could be used in biological and tissue engineering applications.

Modulation of complex permittivity of carbon nanotubes/epoxy foam composites reinforced by three-dimensional woven spacer fabric

3D woven spacer composites (3DWSC) with integrated structure have immense potential as design platforms for high-performance microwave absorbent materials. In this work, the complex dielectric constant of 3DWSC was modulated by the content of carbon nanotubes (CNTs) in the epoxy foam sandwich. The theoretical model was proposed for predicting the dielectric constant of 3DWSC-CNT/epoxy foam. The error between model prediction, measured results and finite element results was less than 5%. The excellent mechanical properties of 3DWSC-CNT/epoxy foam were demonstrated by compression and impact experiments. The absorption performance and radar cross section (RCS) reduction in the frequency range of 4–18 GHz were calculated by finite element method. The maximum effective absorption bandwidth was 5.5 GHz. The RCS of 3DWSC- CNT/epoxy foam of the same size at 10 GHz was only 1% of that of carbon fiber composites. 3DWSC endowed with microwave absorption function have great potential in the practical application of anti-radar detection.

Effect surface micro-wrinkles and micro-cracks on microwave shielding performance of copper-coated carbon nanotubes/polydimethylsiloxane composites

Surface where microwaves reach firstly is significantly important on microwave shielding. However, the construction of surface multiple structure to enhance microwave shielding property is still a great challenge. Herein, conductive micro-cracks and micro-wrinkles are designed on surface of flexible copper/polydimethylsiloxane-carbon nanotubes to enhance excellent shielding performance. The surface microstructures can be tuned by controllably tailoring the carbon nanotube (CNT) concentration, substrate thickness, and pre-stretching strain before copper sputtering deposition. At the same thickness and CNT content, the amount of micro-cracks and micro-wrinkles grows as pre-stretching strain increases, which effectively boosts specific surface area and micro-capacitance effect on the surface, thus enhancing the electromagnetic wave shielding effectiveness of the composites. Meanwhile, the micro-cracks can cause the surface conductivity to be considerably orientated, which in turn severely affected the field distribution and conduction losses on the surface of the composites. Furthermore, the experimental and simulation results are consistent concerning the effect of surface micro-cracks and micro-wrinkles on microwave shielding performance.

The effects of single-walled carbon nanotubes dispersion and agglomeration in aluminum matrix: Fabrication and finite element simulation

This paper provides novel research on the effect of full dispersion and agglomeration of single-walled carbon nanotubes (SWCNT) in the Aluminum (AL) matrix. The effect was investigated using the representative volume element (RVE) and finite element method (FEM). The acquired findings were compared to the experimental method (EXP) to assess the correctness of the employed method. In the investigation to anticipate the SWCNT rule in AL/SWCNT mechanical properties, RVE and FEM approach focused on two primary conditions: SWCNT complete dispersion and via agglomeration. Al/SWCNT was manufactured using powder technology. SEM images revealed that there were local SWCNT agglomerations within the composites at greater carbon nanotube concentrations, resulting in a decrease in the specimens' elastic modulus and mechanical strength. Based on RVE and EXP methods, the elastic modulus was increased until dispersed SWCNTs were added up to 2 wt%, after which the modulus was decreased as more SWCNTs were added. The elastic modulus with EXP was compared to the RVE curve cylinder SWCNT full dispersion and curve cylinder with SWCNT agglomeration results under periodic boundary conditions (PBC). The comparison demonstrated that EXP and RVE were in an acceptance agreement. In addition, AL-SWCNT RVEs were studied under damage condition.

Impact of carbon nanotubes concentrations on the performance of carbon nanotubes/zinc oxide nanocomposite for photoelectrochemical water splitting

Under the influence of visible light, the photoelectrochemical (PEC) method of water splitting offers a green method for producing sustainable hydrogen. In this work, several volume ratios of carbon nanotubes (CNTs) were incorporated in the zinc oxide (ZnO) matrix to prepare ZnO/CNTs nanocomposites on a glass substrate as photoelectrodes for hydrogen production. These electrodes were synthesized via the spray pyrolysis technique and chemical vapor deposition. Various approaches were used to analyze the chemical composition, crystal structure, morphology, and optical properties of pure ZnO and ZnO/CNTs nanocomposites. The structural properties showed that crystallite size is decreased from 44.2 nm to 36.8 nm, and the optical shows that the energy bandgap (Eg) enhanced from 3.07 to 2.87 eV for pure ZnO and the optimum sample of ZnO/7 mL CNTs nanocomposite, respectively. The maximum photocurrent density (Jph) was found for the 7 mL CNTs among the produced ZnO/X CNTs nanostructures. The value of Jph for ZnO/7 mL CNTs (200.7 µA/cm2) is around 33 times greater compared with pure ZnO (6.96 µA/cm2). At 490 nm, the incident photon-to-current efficiency (IPCE) of ZnO/7 mL CNTs is roughly 9.85 %. The ZnO/CNTs photoelectrode showed a hydrogen evolution rate of 4.34 mmole/h.cm2. The improved photoelectrode additionally exhibits strong chemical stability and a lengthy lifetime under visible light without photo-corrosion. Finally, the electrochemical impedance spectroscopy and the PEC water-splitting mechanism for ZnO/CNTs were discussed. This study presents a simple method that enables the fabrication of inexpensive and efficient ZnO/CNTs photoelectrode for renewable energy applications.

Preparation Methods and Properties of CNT/CF/G Carbon-Based Nano-Conductive Silicone Rubber

Carbon-based nano-conductive silicone rubber is a kind of composite conductive polymer material that has good electrical and thermal conductivities and high magnetic flux. It has good application prospects for replacing most traditional conductive materials, but its mechanical and tensile strengths are poor, which limit its applications. In this study, carbon fiber (CF), graphene (G) and carbon nanotubes (CNT) are used as fillers to prepare carbon-based nano-conductive silicone rubber via solution blending, and the preparation methods and properties are analyzed. The results show that when the carbon fiber content is 7.5 wt%, the volume resistivity of carbon fiber conductive silicone rubber is 9.5 × 104 Ω·cm, the surface resistance is 2.88 × 105 Ω, and the tensile strength reaches 2.12 Mpa. When the graphene content is 5.5 wt%, the volume resistivity of graphene conductive silicone rubber is 8.7 × 104 Ω·cm, and the surface resistance is 2.4 × 106 Ω. When the carbon nanotube content is 1.25 wt%, the volume resistivity of carbon nanotube conductive silicone rubber is 1.34 × 104 Ω·cm, and the surface resistance is 1.0 × 106 Ω. The three conductive nano-fillers in the blended carbon nano-conductive silicone rubber form a stable three-dimensional composite conductive network, which enhances the conductivity and stability. When the tensile rate is 520%, the resistance of the blended rubber increases from 2.69 × 103 to 9.66 × 104 Ω, and the rubber maintains good resilience and tensile sensitivity under repeated stretching. The results show that the proposed blended carbon nano-conductive silicone rubber has good properties and great application prospects, verifying the employed research method and showing the credibility of the research results.

The Effect of Heat Treatment on Wear Properties of Ni-B-CNT Electroless Coating with Different Carbon Nanotube Concentration on AISI 4340 Steel

Study wear resistance for heat treatment of Ni-B-CNT electroless coatings. Different concentrations for CNT (0 ,0.35 and 0.7 g/l Ni-B-CNT composite coatings deposition on 4340 steel. After the procedure of coating, all samples were heat treatment. The test wear of a coating was valued with pin on disk technique. Preparation of Ni–B–CNT electroless coatings are with using nickel chloride in alkaline bath, borohydride and Multi walled carbon nanotubes. characterization with FESEM, micro hardness, XRD and surface roughness. Study for surfaces of worn with EDS and FESEM. Micro hardness results are show that the larger hardness1010 HV is gained by heat treatment for coating (Ni-B- 0.35 g/L CNT) because of concentration CNT caused structure conversion for coating Ni-B from amorphous to crystalline. Also, CNT prevent maximum heat production and decrease of the friction coefficient during test wear. CNT aggregation was noted result the presence for more particles (Ni-B - 0.7g/l CNT) that occur create roughness and also lead to increase in rate of wear because of big particles with weakly joined in matrix of Ni.

Laser-Formed Sensors with Electrically Conductive MWCNT Networks for Gesture Recognition Applications.

Currently, an urgent need in the field of wearable electronics is the development of flexible sensors that can be attached to the human body to monitor various physiological indicators and movements. In this work, we propose a method for forming an electrically conductive network of multi-walled carbon nanotubes (MWCNT) in a matrix of silicone elastomer to make stretchable sensors sensitive to mechanical strain. The electrical conductivity and sensitivity characteristics of the sensor were improved by using laser exposure, through the effect of forming strong carbon nanotube (CNT) networks. The initial electrical resistance of the sensors obtained using laser technology was ~3 kOhm (in the absence of deformation) at a low concentration of nanotubes of 3 wt% in composition. For comparison, in a similar manufacturing process, but without laser exposure, the active material had significantly higher values of electrical resistance, which was ~19 kOhm in this case. The laser-fabricated sensors have a high tensile sensitivity (gauge factor ~10), linearity of >0.97, a low hysteresis of 2.4%, tensile strength of 963 kPa, and a fast strain response of 1 ms. The low Young's modulus values of ~47 kPa and the high electrical and sensitivity characteristics of the sensors made it possible to fabricate a smart gesture recognition sensor system based on them, with a recognition accuracy of ~94%. Data reading and visualization were performed using the developed electronic unit based on the ATXMEGA8E5-AU microcontroller and software. The obtained results open great prospects for the application of flexible CNT sensors in intelligent wearable devices (IWDs) for medical and industrial applications.

Effects of MWCNTs content and dry density on hydro-structural characteristics of bentonite during drying and wetting

Bentonite has been an essential component of geosynthetic clay liners due to its low hydraulic conductivity, which has been used as a barrier against hazardous pollutants in landfills. During the drying and wetting processes caused by high temperatures and leachate in landfills, the hydro-structural characteristics of bentonite vary as the moisture content change. This article investigates the effect of dry density and multi-walled carbon nanotubes (MWCNTs) content on the soil shrinkage characteristic curve (SSCC), the soil free-swelling characteristic curve (SFSCC), the soil water characteristic curve (SWCC), and microstructure of bentonite during the drying and wetting processes. Experimental results indicate that the addition of MWCNTs can slow down the volume variation of bentonite at the normal shrinkage stage and at the initial swelling stage and improve the water retention capacity in the low suction range. Meanwhile, reducing bentonite’s dry density can increase the void ratio during drying, decrease the void ratio during wetting, and improve the water retention capacity in the low suction range. Dry density and MWCNTs content both have no influence on the SSCC at the residual shrinkage stage and the zero shrinkage stage, the SFSCC at the residual swelling stage, and the SWCC at the high suction range.

Carbon nanotube production from algal biochar using microwave irradiation technology

In this study, we evaluated the transformation of algal-based biochar into carbon nanotubes by irradiation in a microwave oven at low energies (100–300 W). Three species of algae (Macrocystis pyrifera, Sarcothalia crispata, and Scenedesmus almeriensis) were selected and pyrolyzed to obtain biochar for carbon nanotubes (CNTs) growth in the presence of ferrocene as the catalyst. The CNTs obtained were characterized by dynamic light scattering, UVVIS spectroscopy, Raman spectroscopy, transmission electron microscopy, X-ray diffraction, and electrical conductivity. The results indicate that algal biochar can be used for CNT growth. The heterogeneous structure of algal biochar can initiate the graphitization process for the formation of CNTs. The characteristics of synthesized CNTs vary with the biochar source used as a precursor. Thus, both the degree of graphitization of the wall and the content of nanotubes were higher using biochar with higher carbon content (from microalga Scenedesmus almeriensis); otherwise, the hydrodynamic diameter and electrical conductivity were higher using biochar with upper mineral ash content (from microalga Macrocystis pyrifera). Furthermore, it was found that a low catalyst concentration was required to promote growth due to the reactivity of the mineral ash of the biochar, and it was demonstrated that microwave heating conditions, such as microwave power and temperature, lead to variations in the optical properties of CNTs, such as the band gap energy, CNTs content, and measurement of the size such as the hydrodynamic diameter.

Experimental investigation on fabrication, characterization and properties of spark plasma sintered alumina-based tungsten carbide composites reinforced by carbon nanotubes

In this study, the alumina-based tungsten carbide (WC-Al2O3) composites reinforced by different weight percentages of carbon nanotubes were successfully prepared by the advanced spark plasma sintering technique. This study has the novelty that such composites with the given compositions were never sintered before using spark plasma sintering. The WC-Al2O3-CNTs composites were fabricated to design advanced tool materials with an optimum set of mechanical and thermal properties for high-temperature cutting applications. The experimental results revealed considerable growth in micro-hardness and fracture toughness in WC-Al2O3-CNTs composites as compared to WC-Al2O3 composites. The ideal set of mechanical properties was acquired by WC-Al2O3-CNTs-0.5 composite which also exhibited a minimum value of grain size. At higher concentrations of carbon nanotubes, the mechanical properties of composites tend to degrade due to the agglomeration of carbon nanotubes. The study presented better results in sintered composites than the composites fabricated through other sintering techniques. The improved strengthening and toughening results of WC-Al2O3-CNTs composites along with the fine microstructures were mainly acquired by inhibiting grain growth during sintering, improved dispersion of the constituents in the composites (electron probe microscopy analysis/wavelength dispersive spectroscopy mapping) and consolidation at shorter sintering periods in spark plasma sintering. A thermal study was also conducted to discuss the thermal stability of sintered composites at ambient as well as at higher temperatures to estimate the behavior of thermal conductivity and thermal diffusivity of composites at different temperatures.

Effect of the concentration of carbon nanotubes (CNTs) on the rheological behavior in a lubricating oil of plant-derived lubricant

Nanofluids have attracted a lot of attention since their significant enhancement in thermal properties, however there are few reports on the study of the viscosity of nanofluids from an experimental point of view. In this work, the rheological behavior of functionalized multi-walled carbon nanotubes (F-MWCNTs) and coated with MoS2 (MWCNTs-MoS2) in a commercial palm oil as base fluid was evaluated. The purification and functionalization process of the MWCNTs was performed by acid leaching and investigated by FTIR, and stable nanofluids were prepared with MWCNTs concerning time. The rheological behavior of nanofluids with MWCNTs was performed as a function of temperature at different concentrations (0.1, 0.5 and 1% wt.). The effect of time, temperature, shear rate and shear stress versus shear rate were determined. The results indicate that the nanofluid behaves as a Newtonian fluid independently of the MWCNTs concentrations and temperatures evaluated. The viscosity index increases by 16% at a concentration of 1% wt. of F-MWCNTs and for nanofluids added with MWCNTs-MoS2 had significant effect on the effect of temperature.