Influence Of Single-walled Carbon Nanotubes Research Articles

Influence of SWCNT on shielding and tensile properties of polyurethane nanocomposites

ABSTRACT The effect of single-walled carbon nanotubes (SWCNTs) as fillers in polyurethane matrix composites on the efficiency of attenuating electromagnetic waves in the X-band region (8–12 GHz) was studied in the current work. To meet the present-day challenges, the composites were tested using a tensile system. The inclusion of SWCNT in the polyurethane matrix proved the enhancement of electromagnetic interference shielding performance along with the improved mechanical properties. The composites were characterised by FTIR and FESEM. The dielectric properties were investigated in X-band frequencies. The shielding performance of the samples was found to be 28 dB for 1 wt% filler at 10 GHz. The effect of CNT on the mechanical performance of polyurethane composites was studied. The maximum tensile strength achieved was 2.87 MPa for 3 wt% CNT. The results showed that the synthesised sample materials found more shielding applications with favourable tensile properties.

Exploring the influence of Single-Walled carbon nanotubes substituted Mg–Ti alloy for hydriding and dehydriding properties

Currently, researchers are giving much more attention to carbon allotropes for hydrogen storage applications. SWCNT-(Mg–Ti) composites have been synthesized by the ball milling technique. The XRD patterns confirmed the solid solution formation of Ti in Mg. The substitution of SWCNT in Mg–Ti intermetallic alloy increases the dislocation density to 8.2x10−3nm−2 and reduces the crystal size from 46 to 28 nm and lattice strain of 0.54 to 0.28 %. The Raman analysis confirmed the existence of SWCNTs by presenting D and G bands and also confirmed the vibrations of Mg–Ti alloy. After the substitution of SWCNT, the exothermic peak reduced from 232 °C to 210 °C. The activation energy is also reduced after the substitution of SWCNT; it drastically reduces the activation energy to 66.59 kJ/mol for Mg67Ti29SWCNT4 alloy among the prepared samples. The impedance spectroscopy shows a higher diffusion coefficient of 5.2488x10−11 cm2s−1 for SWCNT substituted Mg–Ti alloy compared to pristine alloy. The hydriding/dehydriding studies were observed on the developed electrode material and Mg67Ti29SWCNT4 delivered a maximum storage capacity of 826 mAhg−1.

The Influence of Single-Walled Carbon Nanotubes on the Aging Performance of Polymer-Modified Binders.

The use of polymer-modified binders in asphalt concrete makes it possible to increase the efficiency and durability of highways. However, at present, there is an important and unresolved problem in this area, making it impossible to fully exploit the potential of modified binders. This is a tendency of aging processes that leads to the premature destruction of the pavement. In many literary sources, it is reported that reasons are related to the peculiarity of the chemical composition and occur at the submicron level. Therefore, the influence of single-walled carbon nanotubes has been studied for a better understanding of aging processes. The aging processes of the RTFOT (rolling thin film oven test) and PAV (pressure aging vessel) modified with SBS (styrene-butadiene-styrene) polymer, single-walled carbon nanotubes, and waste industrial oil were simulated in a laboratory furnace. Microstructural features were studied using the method of infrared spectral analysis. The dependences of viscoelastic properties on the component composition of binders were investigated. The optimal content of single-walled carbon nanotubes (0.001%), SBS (styrene-butadiene-styrene) polymer (3.5%), and waste industrial oil (4%) in the binder composition was established, which synergistically improved the performance of the modified binder from PG (52-22) (performance grade) to PG (64-34). It was established that single-walled carbon nanotubes provide improvement in the durability parameter ∆Tc binder by 150%, improved relaxation properties at low temperatures, and resistance to fatigue damage.

Analysis of the Influence of Single-Walled Carbon Nanotubes on the Fluid–Structure Interaction Vibration Control in Bionic Hydraulic Pipelines

In previous research, a bionic hydraulic pipeline (BHP) with a three-layer structure for absorbing pulsation was invented. This paper proposes to disperse single-walled carbon nanotubes (SWCNTs) in the elastic layer material, namely silicone rubber (RTV), to enhance its ability to absorb pulsation. Firstly, the RTV-SWCNTs composite specimens with different SWCNT proportions are prepared and tested. It was found that the mechanical property is optimal when the volume content of the SWCNTs is 0.5 vol%. On this basis, BHPs with RTV-SWCNTs composite material as the elastic layer are fabricated to study the influence of the thickness and length of the elastic layer on the absorption flow pulsation. The results show that the addition of SWCNTs significantly improves the mechanical properties of silicone rubber and reduces the friction between the elastic material and oil, so that the BHP can absorb the pressure pulsation better. With the appropriate thickness and length of the elastic layer, the addition of SWCNTs can increase the pulsation suppression effect by 20%. Moreover, to analyze the influence of nanomaterials on pipeline friction, a comprehensive fourteen-equation model for describing the fluid–structure interaction (FSI) of the pipe conveying fluid considering friction coupling is established. And through numerical analysis and modal tests, the evaluation error for the modified dynamic model of the BHP is less than 5%, verifying the correctness of the proposed model and solution method.

Influence of Single-Wall Carbon Nanotube Suspension on the Mechanical Properties of Polymeric Films and Electrospun Scaffolds.

Carbon nanotubes (CNTs) are used in applications ranging from electrical engineering to medical device manufacturing. It is well known that the addition of nanotubes can influence the mechanical properties of various industrial materials, including plastics. Electrospinning is a popular method for fabricating nanomaterials, widely suggested for polymer scaffold manufacturing. In this study, we aimed to describe the influence of single-walled carbon nanotube (SWCNT) suspensions on polymeric poured films and electrospun scaffolds and to investigate their structural and mechanical properties obtained from various compositions. To obtain films and electrospun scaffolds of 8 mm diameter, we used poly-ε-caprolactone (PCL) and poly(cyclohexene carbonate) (PCHC) solutions containing several mass fractions of SWCNT. The samples were characterized using tensile tests, atomic force and scanning electronic microscopy (AFM and SEM). All the studied SWCNT concentrations were shown to decrease the extensibility and strength of electrospun scaffolds, so SWCNT use was considered unsuitable for this technique. The 0.01% mass fraction of SWCNT in PCL films increased the polymer strength, while fractions of 0.03% and more significantly decreased the polymer strength and extensibility compared to the undoped polymer. The PHCH polymeric films showed a similar behavior with an extremum at 0.02% concentration for strength at break.

Ecotoxicological influence of single-walled carbon nanotubes, graphene nanoribbons, and graphene quantum dots on marine microalgae

Ecotoxicological influence of single-walled carbon nanotubes, graphene nanoribbons, and graphene quantum dots on marine microalgae

Effect of Single Walled Carbon Nanotubes on the Series Resistance and Trap Energy of Malachite Green Dye Based Organic Device

In this paper, we have estimated the series resistance (Rs) and the trap energy (Ec) of the sandwiched type Malachite Green (MG) dye-based organic device and have also observed the influence of single-walled carbon nanotubes (SWCNT) on both of these parameters. To form the organic device, we have used Indium Tin Oxide (ITO) coated glass as the front electrode and Aluminium (Al) as a back electrode by using the spin coating technique. The values of series resistance are measured from both I-V characteristics and by utilizing Cheung Function due to the non ideal behavior of organic devices. We have also extracted the values of Rsby using H (I) versus I plot and verified the values with the measured values of Rsfrom the Cheung function. The extracted values of series resistance using these three processes remain consistent with each other in showing that the values of series resistance have been reduced considerably in the presence of SWCNT. The trap energy has been estimated from the steady-state current-voltage characteristics. There is a significant correlation in between series resistance and the trap energy of the organic device. The presence of Single-Walled Carbon Nanotubes reduces the trap energy from 0.086 eV to 0.057 eV. Lowering of the trap energy of the metal-organic layer interface in presence of Single Walled Carbon Nanotubes attributes to the reduction of the value of the series resistance. The extracted value of Rsdecreases from 0.154 MΩ to 0.0389 MΩ in presence of SWCNT. Decrease in the value of both of these parameters in the presence of SWCNT will definitely improve the charge transport mechanism of the organic device and thereby the conductivity.

Influence of Carbon Primary Nano Materials in Polymer Modified Binders on the Temperature Sensitivity of Asphalt Concrete During Operation

The influence of the content of single-walled carbon nanotubes on the basic physical and mechanical properties of polymer-bitumen binders is studied. The effect of nanomodifiers on the morphostructural features of polymer-bitumen binders was studied using optical methods and fluorescence microscopy. The rational content of the modifying additive (0.0001 %) in the composition of the binder, which ensures the achievement of the specified parameters, is established. The influence of single-walled carbon nanotubes on morphostructural features is established. the nanomodifier initiates the processes of structuring interfacial layers, which leads to strengthening of physical bonds between the polymer macromolecules and the dispersed phase of the organic binder, which naturally affects the improvement of heat resistance, adhesive and cohesive strength of the binder. The study of polymer-bituminous binder films allowed us to record that when the nanomodifier is introduced, the polymer macromolecules decrease and their distribution over the binder volume is more uniform, which ensures its stability. It was found that the introduction of a rational amount of nanomodifier allows you to expand the required temperature range of asphalt concrete pavement performance by 25-34 %, while reducing the polymer content by 38 %.

Влияние добавок углеродных нанотрубок и оксидных нановолокон на механические свойства алюминия АД0 после термомеханической обработки

Cast aluminium composite materials based on AD0 aluminium, reinforced with carbon nanotubes and aluminium oxide nanofibers are obtained. It is shown that the additives of 0.05 wt % of single wall carbon nanotubes (SWCNT) and aluminum oxide nanofibers (AONF) allow increasing ultimate tensile strength of cast metal by 15 % and 16 % respectively. Strengthening of the metal is maintained after cold deformation and annealing. Aluminum AD0 with additives SWCNT or AONF retains high strength after annealing, while aluminum without additives is significantly weakened, this allows to obtain annealed aluminum wire, with a strength limit of 54 – 69 % and yield strength of 53 – 78 % higher than that of metal without additives. The influence of SWCNT and AONF on the size of aluminum grain AD0 in the cast state, after cold deformation and annealing has been studied. Nano-additives have been found to inhibit the growth of metal grains at the stage of collective recrystallization, as well as to influence the process of primary recrystallization of aluminum.

A comparative study of the incorporation effect of SWCNT-OH and DWCNT with varied microstructural defects on tensile and impact strengths of epoxy based nanocomposite

This study presents an investigation of the influence of Single-Walled Carbon Nanotubes (SWCNTs) and Double-Walled Carbon Nanotubes (DWCNTs) on tensile and impact strengths of epoxy based nanocomposites. Two different CNTs weight percentages were employed including 0.5 and 0.75 wt.% in order to verify their effects on microstructures and mechanical properties. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) were used to analyze the microstructural characteristics of the CNT doped epoxy including presence of defects such as air bubbles, tiny pores and aggregates. DWCNTs/epoxy nanocomposites presented higher amount of pores due to lack of functionalization, while SWCNTs/epoxy ones showed more entanglement mostly at high CNT loading due to its larger aspect ratio. Results showed that tensile strength was slightly enhanced (6 %) for 0.5 wt.% SWCNT, whereas for other nanocomposites it reduced in comparison with the neat epoxy, due to presence of manufacturing defects in the material. Impact strength significantly improved by 51 % and 31 % at 0.5 wt.% SWCNTs and 0.5 wt.% DWCNTs, respectively, resulting from activation of crack bridging and CNTs pull-out mechanisms. Different behaviours between tensile and impact tests are related to homogeneous stress distribution and localized stress concentration in tensile and impact tests, respectively.

The Influence of Single-Walled Carbon Nanotubes on the Dynamic Properties of Nematic Liquid Crystals in Magnetic Field.

This article aims to study the impact of carbon nanotube dispersions in liquid crystals. A theoretical model for the system’s dynamics is presented, considering the elastic continuum theory and a planar alignment of liquid crystal molecules on the nanotube’s surface. Experimental calculation of the relaxation times in the magnetic field was made for two cases: when the field was switched on (τon), and when it was switched off (τoff). The results indicate an increase of the relaxation time by about 25% when the magnetic field was switched off, and a smaller increase (about 10%) when the field was switched on, where both were in good agreement with the theoretical values.

Influence of single-walled carbon nanotubes induced exciton dissociation improvement on hybrid organic photovoltaic devices

Torch-plasma-grown single-walled carbon nanotubes (SWCNTs) are integrated with regioregular poly(3-hexylthiophene) (P3HT) and a fullerene derivative 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61 (PCBM) as a hybrid photoactive layer for bulk heterojunction solar cell devices. We demonstrate that molecular information could be accurately obtained by time-of-flight secondary ion mass spectrometry throughout the hybrid organic photoactive solar cell layers when sputtering is performed using a Cs+ 2000 eV ion source. Furthermore, the photovoltaic (PV) performance of the fabricated devices show an increase in the short-circuit current density (Jsc) and the fill factor (FF) as compared to the pristine devices fabricated without SWCNTs. The best results are obtained with 0.5 wt. % SWCNT loads, where an open-circuit voltage (VOC) of 660 mV is achieved, with a Jsc of 9.95 mA cm−2 and a FF of 54%, leading to a power conversion efficiency of 3.54% (measured at standard test conditions, AM1.5 g). At this optimum SWCNT concentration of 0.5 wt. %, and to further understand the charge-transfer mechanisms taking place at the interfaces of P3HT:PCBM:SWCNT, Jsc is measured with respect to the light intensity and shows a linear dependency (in the double logarithmic scale), which implies that losses in the charge carrier are rather governed by monomolecular recombination. Finally, our results show that our hybrid devices benefit from the fullerene electron accepting nature and from the SWCNT fast electron transportation feature that improve substantially the exciton dissociation efficiency. The influence of the SWCNTs on the Fermi level and the work function of the photoactive composite and its impact on the PV performance is also investigated.

Alumina-based composites reinforced with single-walled carbon nanotubes

Monolithic Al2O3 ceramics and Al2O3 - 3 vol% single-walled carbon nanotubes (SWCNTs) composites were prepared by spark plasma sintering. The influence of SWCNTs and sintering temperature on sintering behavior and mechanical properties were investigated. Nanotubes were relatively homogeneously distributed in the composite powder, although some agglomerates/bundles existed. It was found that SWCNTs addition retards slightly the sinterability of alumina by nanotubes hindering of particle rearrangement. The average microhardness of the composites was lower than that of Al2O3 ceramics, but there were also high microhardness values of composites (20.41 GPa). The reduction in microhardness is explained in this paper. The average values of the fracture toughness (4.94 MPa-m1/2) from the composite sintered at 1500 °C were approximately 6% and 12% higher than those from the Al2O3 ceramics sintered at 1500 °C and 1600 °C, respectively. In addition, the analysis of the phase composition and the parameters of the crystal structure of the samples were made.

Polyaniline photoluminescence quenching induced by single-walled carbon nanotubes enriched in metallic and semiconducting tubes

The influence of single-walled carbon nanotubes enriched in semiconductor (S-SWNTs) and metallic (M-SWNTs) tubes on the photoluminescence (PL) of polyaniline (PANI), electrosynthesized in the presence of the H2SO4 and HCl solutions, is reported. The emission bands peaked at 407–418 and 440–520 nm indicate that the electropolymerization of aniline (ANI) leads to the formation of short and longer macromolecular chains (MCs), respectively. We demonstrate that the reaction product consists of ANI tetramers (TT) and trimers (TR) as well as PANI-salt. Using Raman scattering and IR absorption spectroscopy, a covalent functionalization of SWNTs with shorter and longer MCs of PANI-salt is demonstrated. The presence of S-SWNTs and M-SWNTs induces a decrease in ANI TT weight in the reaction product mass consisting in S-SWNTs and M-SWNTs covalently functionalized with PANI-emeraldine salt (ES) and PANI-leucoemeraldine salt (LS), respectively. A PANI PL quenching is reported to be induced of the S-SWNTs and M-SWNTs. A de-excitation mechanism is proposed to explain PANI PL quenching.

Synthesis, characterization, and interactions of single-walled carbon nanotubes modified with doxorubicin with Langmuir\u2013Blodgett biomimetic membranes

The synthesis, characterization, and the influence of single-walled carbon nanotubes (SWCNTs) modified with an anticancer drug doxorubicin (DOx) on the properties of model biological membrane as well as the comparison of the two modes of modification has been presented. The drug was covalently attached to the nanotubes either preferentially on the sides or at the ends of the nanotubes by the formation of hydrazone bond. The efficiency of the modification was proved by the results of FTIR, Raman, and thermogravimetric analysis. In order to characterize the influence of SWCNT-DOx conjugates on model biological membranes, Langmuir technique has been employed. The mixed monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) and SWCNT-DOx with different weight ratio have been prepared. It has been shown that changes in the isotherm characteristics depend on the SWCNTs content. While smaller amounts of SWCNTs do not exert significant differences, the introduction of the prevailing content of the nanotubes increases area per molecule and decreases the maximum value of compression modulus, leading to more fluid monolayer. However, upon increasing the surface pressure, the aggregation of carbon nanotubes within the thiolipid matrix has been observed. Mixed layers of DPPTE/SWCNT-DOx were also transferred onto gold electrodes by means of LB method. Cyclic voltammetry showed that SWCNT-DOx conjugates remain adsorbed at the electrode surface and are stable in time. Additionally, higher values of peak current and DOx surface concentration obtained for side modification prove that side modification allows for more efficient conjugation of the drug to carbon nanotubes.Graphical abstractᅟ

Influence of single-walled carbon nanotubes’ diameter and length on the thermal conductivity of polymer composites

Physical properties of composite materials can be improved by carbon nanotubes (CNTs). However, the thermal resistance between the polymer matrix and CNT at nanoscale can result in lower thermal conductivity. The paper analyses influence of CNTs’ diameter and length on effective thermal conductivity in epoxy-based composites. It analyses the effect of the diameters, lengths and volumetric fraction of CNT on composites’ thermal conductivity.

Pyrene containing liquid crystalline asymmetric phthalocyanines and their composite materials with single-walled carbon nanotubes

In the present work we have studied the dispersion of single-walled carbon nanotubes in liquid crystalline asymmetrically substituted phthalocyanines (MPc, where M [Formula: see text] Cu, Co, and 2H) bearing one pyrene and six polyoxy groups as side chains. The influence of single-walled carbon nanotubes on the phase behavior of MPcs was investigated using X-ray diffraction, polarized optical microscopy and differential scanning calorimetry. It was demonstrated that the incorporation of small amounts of single-walled carbon nanotubes ([Formula: see text]1 wt.%) does not alter the MPc mesophases. The structural features and the sensor response of composite thin films of MPc with single-walled carbon nanotubes to ammonia vapor (10–50 ppm) was studied and compared with those of the films of pure MPc derivatives.

Influence of Single-Walled Carbon Nanotubes on the Performance of Poly(Azomethine-Ether) Composite Materials

ABSTRACTThe present work is aimed to fabricate a new set of composite materials containing conducting poly(azomethine-ether) reinforced with single-walled carbon nanotubes in the form of single-walled carbon nanotube/poly(azomethine-ether)1–5 for excellent enhanced thermal as well as conducting behavior of poly(azomethine-ether). Single-walled carbon nanotubes of variable loading have been embedded into conducting poly(azomethine-ether) using in situ polymerization technique. Before attempting the polymerization, 1,3-thiazole established poly(azomethine-ether) and its conformable monomers have been prepared and their chemical structures have been correlated by spectral analyses. Furthermore, ηinh and Mw values for poly(azomethine-ether) were found 0.89 dL g−1 and 39723.6, respectively. The fabricated single-walled carbon nanotube/poly(azomethine-ether)1–5 composites were specified and characterized by wide-angle X-ray diffraction patterns, Fourier transform infrared spectroscopy, thermal behavior, scanning electron microscopy, and transmission electron microscopy characterization techniques. A perfect indicative response for this composite material was estimated by Fourier transform infrared spectra and X-ray diffraction as well. Both techniques displayed all intensive characteristic peaks regarding single-walled carbon nanotubes and poly(azomethine-ether) in the spectra or diffraction pattern for single-walled carbon nanotube/poly(azomethine-ether)1–5. The role of single-walled carbon nanotubes on the performance of poly(azomethine-ether) was considerably examined. Single-walled carbon nanotube/poly(azomethine-ether)1–5 showed relatively higher thermal stability. Single-walled carbon nanotube/poly(azomethine-ether)1 displayed the lowest final composite degradation temperature value (552°C), whereas single-walled carbon nanotube/poly(azomethine-ether)5 displayed the highest value (621°C). T10 and T25 values showed a gradual temperature increased while single-walled carbon nanotubes increased. Single-walled carbon nanotube/poly(azomethine-ether)1 showed the lowest thermal stability and single-walled carbon nanotube/poly(azomethine-ether)5 showed the highest thermal stability between all fabricated products. Furthermore, transmission electron microscopy images showed a prominent increase in single-walled carbon nanotubes diameters (40–60 nm). The conductivity values were significantly increased while single-walled carbon nanotubes content was increased and reached to the semiconductors. ε′ values were also increased in both single-walled carbon nanotube/poly(azomethine-ether)4,5 which have higher single-walled carbon nanotubes content.

The influence of single-walled carbon nanotubes on optical properties of the poly[(2,5-bisoctyloy)-1, 4-phenylenevinylene] evidenced by infrared spectroscopy and anti-Stokes photoluminescence

Significant differences are reported for the IR spectra of poly[(2,5-bisoctyloy)-1, 4-phenylenevinylene] (BO-PPV) recorded onto the KBr, Ag and Au supports. In this work, a decrease in the absorbance of the IR spectra of the BO-PPV films deposited onto Au and Ag supports as increasing the macromolecular compound film thickness is reported. A preferential orientation of the BO-PPV molecules and its composite with single-walled carbon nanotubes (SWNTs) versus metallic supports of Ag and Au is assessed using the IR absorption spectroscopy under s and p polarized light. An anti-Stokes photoluminescence (ASPL) is reported to characterize the BO-PPV macromolecular compound. The BO-PPV ASPL spectra intensity dependent both of the thickness of the macromolecular compound layer deposited onto the metallic supports and the SWNTs weight in the BO-PPV/SWNTs composite mass.

Influence of single-walled carbon nanotubes enriched in semiconducting and metallic tubes on the electropolymerization of tetrabromo ortho-xylene: Insights on the synthesis mechanism of poly(ortho-phenylenevinylene)

New composite materials based on single-walled carbon nanotubes effectively separated into semiconducting (S-SWNTs) and metallic tubes (M-SWNTs) and poly(ortho-phenylenevinylene) (POPV) were synthesized by the electrochemical polymerization of the α,α,α′,α′-tetrabromo-o-xylene monomer onto the surface of Au supports covered with carbon nanotubes films. Using FTIR spectroscopy, an increase of the quinoid structure weight is highlighted when a charge transfer is induced to take place between the two constituents of the POPV/S-SWNT composite material. In addition, a down-shift of the Raman line belonging to POPV (from 530cm−1 to 515cm−1), which was accompanied by an increase in relative peak intensity, is reported as a result of steric hindrance effects induced by the covalent bonding of POPV onto the S-SWNT surface. The non-covalent functionalization of M-SWNTs with POPV is demonstrated to occur by Raman scattering and FTIR spectroscopy. The photoluminescence (PL) spectrum of POPV exhibits two bands at 2.82 and 2.25eV, which were assigned to the electronic emission transitions of macromolecular chains having 3 and 7–10 repeating units, respectively. We demonstrate that POPV photoluminescence quenching in the presence of M+S-SWNTs, M-SWNTs and S-SWNTs is achieved by tubes with chirality (14,7), (12,10) and (11,9), respectively.