Presence Of Multi-walled Carbon Nanotubes Research Articles

Effects of grinding α–β Titanium with 3% CNTs in CBN grinding wheel: An Experimental Study

Carbon Nano Tubes (CNTs) have found an immovable niche in the world of manufacturing in the form of reinforcements in composites. Their many advantageous properties have allowed their usage in innumerable ways and this has led to a plethora of innovations in engineering. In advanced manufacturing of very-hard-to-machine materials like titanium, where surface integrity is of prime importance, the presence of multi-walled CNTs even as less as 3% alongside Cubic Boron Nitride (CBN) in grinding wheels, has demonstrated improved surface finish on Titanium alloy (Ti-6Al-4V). This proposed grinding wheel for use on Titanium, reduces surface roughness and improves Material Removal Rate (MRR) on the Titanium work pieces. It also shows slight improvement in the contour of the wheel.

Reciprocal effects of multi-walled carbon nanotubes and oppositely charged surfactants in bulk water and at interfaces

In this work we made the complementary use of nuclear magnetic resonance spectroscopy, dynamic light scattering, electric conductivity and surface tension methods to study the micellization of cationic surfactants cetyl trimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB), as well as anionic surfactant sodium dodecyl sulfate (SDS) in the presence of multi-walled carbon nanotubes (CNT). It was shown that the CNTs is effectively dispersed in water medium due to the adsorption of surfactant ions at CNT surface. The NMR spectral analysis (chemical shifts and line broadening) specified that surfactants interact with CNTs surface both by alkyl chains and by charged head groups. For cationic CTAB and DTAB this interaction occurs mainly through methylene (CH2)n groups of alkyl radicals, at the same time, the anionic SDS interacts with the CNTs surface by terminal methyl groups (CH3). Interaction specificity of cationic and anionic surfactants leads to their different structural organization to CNT surface. Experimental observations make it possible to propose the model where the attraction of cationic DTAB and CTAB positively charged head groups with negatively charged CNT surface results to the orientation of cationic surfactants along CNT surface. In contrast to positively charged DTAB and CTAB the repulsion of SDS with negatively charged head group from CNT surface and contacted SDS terminal groups results in the normal orientation of anionic surfactant to CNT surface. The consistency of proposed orientation model arrived from conductivity study of surfactant-CNT dispersions. According to conductivity data, the non-micellized cationic surfactants follow complete dissociation in the presence of CNT no matter are they free or bound to CNT. On the contrary the absence of complete dissociation of anionic surfactant in the pre-micellar systems may be the result of SDS ordering on CNT surface and forming the charged surface with double electric layer binding the portion of counter-ions.

Decolourization of Acid Orange 74 Aqueous Solutions in Presence of Multi-Walled Carbon Nanotubes under Ultrasound Irradiation

Few researches focused on the combination of ultrasound and multi-walled carbon nanotubes (MWCNT) in wastewater treatment. In this study, it was found that the combination of ultrasound and MWCNT was more effective in the removal of Acid orange 74 (AO 74) in comparison to single method. And there was a remarkable synergistic effect in the ultrasound/MWCNT combined system. The adsorption behaviour of AO 74 by the combination of ultrasound and multi-walled carbon nanotubes (MWCNT) was investigated under various experimental conditions. The adsorption performance was slightly inhibited with increasing temperature. This fact showed that the adsorption process was exothermic. The removal ratio was improved with increase in MWCNT dosage, which could be attributed to the increased adsorption sites and increased surface area. The dye removal decreasedfrom 96.0 to 41.5% with an increase in the initial concentration of dye from 15 to 100 mg/L. Lower removal ratios at higher dye concentrations were due to the saturation of adsorption, though the adsorption capacity increased from 14 to 41.5 mg/g. It may be due to the high concentration of dye which can provide a high driving force of concentration gradient to overcome all mass transfer resistance. With the increase in pH, removal ratios of AO 74 decreased gradually from pH 3 to 11. At low pH values, the surface of the adsorbent solids was positively charged and easily adsorbed the AO 74 ions having negative charges. But at high pH values, the surface charge of MWCNT got negatively charged, which did not favour the adsorption of negatively charged dye anions. Experimental isotherm data were represented with Langmuir and Freundlich adsorption models. Langmuir isotherm equation fitted better than Freundlich isotherm equation for this system, which meant adsorption of dye onto MWCNT was monolayer adsorption with a finite number of identical sites. The adsorption of AO 74 followed pseudo second-order kinetics. Kinetics analysis suggested lower temperature was favourable for AO 74 adsorption on MWCNT under ultrasound and justified the exothermic adsorption process.

Analysis of mechanical and thermal properties of epoxy multiwalled carbon nanocomposites

The main objective of this study was to investigate the efficiency of the sonication process and of multi-walled carbon nanotubes (MWCNTs) content on the mechanical and thermal properties of an epoxy matrix. Three different sonication powers (25, 50 and 75 W) were used to disperse the MWCNTs (0.2%, 0.4% and 0.6% wt.) in the epoxy matrix. Tensile tests were performed to determine the mechanical properties of the nanocomposites, while the thermal properties were determined by the thermogravimetric analysis (TGA) and the Differential Exploratory Calorimetry (DSC). Finally, a SEM analysis was used to investigate the morphology of the tensile fractured surface and the dispersion of the nanotubes in the polymeric matrix, since the quality of dispersion influences the mechanical and thermal properties of nanocomposites. It was found that the addition of carbon nanotubes to the epoxy matrix and the parameters of the sonication process affect the mechanical and thermal properties of nanocomposites. An increase of approx. 14% in tensile strength and 15% of Young’s modulus, when compared to the pure epoxy matrix was found for 75 W sonication power output and 0.6% MWCNTs weight percentage. The thermal analysis indicated that the presence of MWCNTs increased the Tonset of the nanocomposites when compared to pure epoxy resin. Finally, increasing the sonication power output leads to higher Tg of the nanocomposites studied here.

Antagonistic effects of multi-walled carbon nanotubes and BDE-47 in zebrafish (Danio rerio): Oxidative stress, apoptosis and DNA damage

In natural environments, organisms are often exposed to several environmental pollutants at any one time, and the potential effects of such co-exposures on human and environmental health are of considerable concern. It is thought that multi-walled carbon nanotubes (MWCNTs) may interact with other pollutants in aquatic systems and induce considerably different effects compared with exposure to a single contaminant. The objective of this study was to evaluate the potential acute combined effects of mixtures of MWCNTs and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on embryonic development stages, oxidative stress, apoptosis and DNA damage in developing zebrafish (Danio rerio). The embryos were treated with BDE-47 (5, 10, and 50 μg/L) and MWCNTs (50 mg/L), either combined or individually, for 96 h. Following exposure, BDE-47 induced significant acute toxicity, while the MWCNTs exhibited slight toxicity. When compared with BDE-47-only exposure, the inhibited growth induced by BDE-47 was weakened in the presence of MWCNTs. Similarly, the levels of oxidative stress biomarkers (reactive oxygen species, superoxide dismutase, catalase activities and malondialdehyde), apoptosis (apoptosis rate, caspase-3 and caspase-9 activities) and DNA damage (comet assay and comet olive tails) decreased in the presence of MWCNTs compared to those exposed to BDE-47 alone. These results demonstrate that MWCNTs can weaken the developmental inhibition, oxidative stress, apoptosis and DNA damage induced by BDE-47 in the early stages of zebrafish development.

Enhanced Functional Properties of Low-Density Polyethylene Nanocomposites Containing Hybrid Fillers of Multi-Walled Carbon Nanotubes and Nano Carbon Black.

In this work, hybrid filler systems consisting of multi-walled carbon nanotubes (MWCNTs) and nano carbon black (nCB) were incorporated by melt mixing in low-density polyethylene (LDPE). To hybrid systems a mixture of MWCNTs and nCB a mass ratio of 1:1 and 3:1 were used. The purpose was to study if the synergistic effects can be achieved on tensile strength and electrical and thermal conductivity. The dispersion state of carbon nanofillers in the LDPE matrix has been evaluated with scanning electron microscopy. The melting and crystallization behavior of all nanocomposites was not significantly influenced by the nanofillers. It was found that the embedding of both types of carbon nanofillers into the LDPE matrix caused an increase in the value of Young’s modulus. The results of electrical and thermal conductivity were compared to LDPE nanocomposites containing only nCB or only MWCNTs presented in earlier work LDPE/MWCNTs. It was no synergistic effects of nCB in multi-walled CNTs and nCB hybrid nanocomposites regarding mechanical properties, electrical and thermal conductivity, and MWCNTs dispersion. Since LDPE/MWCNTs nanocomposites exhibit higher electrical conductivity than LDPE/MWCNTs + nCB or LDPE/nCB nanocomposites at the same nanofiller loading (wt.%), it confirms our earlier study that MWCNTs are a more efficient conductive nanofiller. The presence of MWCNTs and their concentration in hybrid nanocomposites was mainly responsible for the improvement of their thermal conductivity.

Cloud Point Extraction in Presence of Multi-walled Carbon Nanotubes for Removal of Direct Green 26 from Aqueous Solutions: Optimization by Box-Behnken Design and Desirability Functions

The novel approach of cloud point extraction in the presence of multi-walled carbon nanotubes (CPE/MWCNTs) is presented for removal of Direct Green 26 (DG26) from aqueous solutions. The experiments were conducted based on the Box-Behnken experimental design and the removal process was optimized by the response surface modeling and desirability function (DF) approach. Effects of the experimental variables (MWCNTs amount, solution pH, clouding time and volume of Triton X-100 solution) on the process efficiency were modeled using a quadratic equation with the coefficient of determination (R2) value of 0.9944 and Fisher ratio of 177.07. Using the DF approach, optimum levels of the variables determined as MWCNTs amount of 0.7 mg, pH 3, clouding time of 40 min and Triton X-100 solution volume of 993 µL. Experimental checking of the conditions resulted in the dye removal efficiency of 95.86%. Results of the study proved the applicability of the proposed method for DG26 removal from real water samples.

Preparation of stable metal/COOH-MWCNT hybrid nanofluid

Multiwall carbon nanotube (MWCNT) nanofluid have potential to deliver high rate of heat transfer due to the presence of MWCNT which are having high thermal conductivity. Dispersion of MWCNT in polar basefluid is a difficult task because MWCNT are hydrophobic in nature which makes their utilization as a heat transfer fluid challenging. Metal nanoparticles can be attached with MWCNT which can possibly improve their dispersion. These nanofluid are called as hybrid nanofluid. The present study investigates the dispersion stability of hybrid of COOH-functionalized multi-walled carbon nanotubes (COOH-MWCNT) with different metals such as silver (Ag/COOH-MWCNT), copper (Cu/COOH-MWCNT), iron (Fe/COOH-MWCNT) and zinc (Zn/COOH-MWCNT) dispersed in distilled water as a basefluid. Chemical reduction method was used to synthesize hybrid nanoparticles by reducing metal cations in the presence of MWCNT. Dispersion of hybrid metal-MWCNT hybrid has been investigated by spectra analysis method (UV–Vis spectrophotometer) and zeta potential. Scanning electron microscope imaging with EDAX confirmed distribution of metal nanoparticle on the MWCNT surface. Thermal conductivity was measured using KD2 pro thermal analyzer. Results revealed that the sequence of dispersion stability and thermal conductivity of prepared nanofluid was Cu/COOH-MWCNT > Fe/COOH-MWCNT > Ag/COOH-MWCNT > Zn/COOH-MWCNT in distilled water.

Stress-induced stabilization of pyrolyzed polyacrylonitrile and carbon nanotubes electrospun fibers

The unique properties of graphitic carbons have gained widespread attention towards their development and application. Carbon materials can be synthesized by thermal decomposition and, more specifically, carbon pyrolysis from polymer precursors. The paper shows the pyrolysis process of polyacrylonitrile (PAN) in the presence of multi-walled carbon nanotubes (MWCNTs) according to different manufacturing process conditions. The electrospinning process of the PAN-MWCNTs solution on multi-plates collectors was firstly analyzed. The morphology and the particles arrangement of the electrospun fibers was studied under scanning and transmission electron microscopes. Moreover, the composite fibrous mats were characterized by RAMAN spectroscopy to identify the effects of a mechanical tension application during the thermal stabilization phase performed before the pyrolysis treatment to obtain carbon fibers from the precursor polymer. The results show that the graphitization of the pyrolyzed fibers is enhanced by the combination of MWCNTs and a mechanical stress applied during the thermal treatment.

Effects of multi-walled carbon nanotubes on the enantioselective toxicity of the chiral insecticide indoxacarb toward zebrafish (Danio rerio)

The mass production and usage of carbon nanotubes (CNTs) have led to the inevitable release into the environment, and the effects of CNTs on the toxicity of co-existing pollutants have been well documented. However, knowledge of the effects of CNTs on the enantioselective toxicity of chiral compounds is limited. Using zebrafish as an experimental model, the enantioselective expression of the apoptosis, CYP3C and EAAT-related genes were analyzed following exposure to multi-walled carbon nanotubes (MWCNTs) (0.05 and 0.5 mg/L), rac-/R-/S-indoxacarb (0.01 mg/L), or the combination of rac-/R-/S-indoxacarb mixed with MWCNTs for 28d. Sex-specific differences were observed in both the liver and brain of zebrafish. The expression of apoptosis and CYP3C-related genes was 16.55–44.29 times higher in the livers of males treated with R-indoxacarb than in S-indoxacarb treated groups. The EAAT-related genes were expressed at 1.38–2.56 times higher levels in the brain of females treated with R-indoxacarb than in S-indoxacarb-treated groups. In the presence of MWCNTs, the expression of caspase-3, cyp3c3, cyp3c4, eaat1a, eaat1b and eaat2 in the livers of males and brains of females treated with S-indoxacarb were 1.65–15.33 times higher than in fish treated with R-indoxacarb. Based on these results, MWCNTs affected the enantioselective toxicity of indoxacarb toward zebrafish.

Rational integration of porous organic polymer and multiwall carbon nanotube for the microextraction of polycyclic aromatic hydrocarbons.

By integration of benzene-constructed porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT), a MWCNT-KBF hybrid material was constructed through in situ knitting benzene with formaldehyde dimethyl acetal inthe presence of MWCNTs to form anetwork. MWCNT-KBF was then adopted as a novel solid-phase microextraction (SPME) fiber coating. Coupled togas chromatography-flame ionization detection, the MWCNT-KBF-assisted SPME method showed large enhancement factors (483-2066), low limits of detection (0.04-0.12μgL-1), good linearity (0.13-50μgL-1), and acceptable reproducibility (4.2-10.2%) for the determination of polycyclic aromatic hydrocarbons (PAHs). The method recoveries of seven PAHs were in the range 80.1-116.3%, with relative standard deviations (RSDs) ranging from 3.5 to 11.9%. The SPME method was successfully applied to the determination of PAHs in river, pond, rain, and waste water, providing a good alternative for monitoring trace level of PAHs in environmental water. Graphical abstract Schematic representation of the rational integration of porous organic polymer (KBF) and multiwalled carbon nanotube (MWCNT) to form a MWCNT-KBF hybrid material through in situ knitting benzene with formaldehyde dimethyl acetal at the presence of MWCNT.

Statistical methods for determining rheological parameters of mortars modified with multi-walled carbon nanotubes

This paper investigates the influence of composition in the presence of multi-walled carbon nanotubes (MWCNT) on the rheological properties of mortars over the time. A rheometer Viskomat NT was used to assess rheological parameters, yield stress and plastic viscosity. On the basis of rheological results, a statistical model of composition variability on the rheological parameters of mortars in the presence of MWCNT was determined by the multiple regression method. The significance of the influence of variable factors and their interactions on parameter of yield stress and plastic viscosity was presented by means of ANOVA. It was found that w/c ratio has the most significant influence on rheological properties mortar modified with MWCNT, for both yield stress and plastic viscosity. For the yield stress parameter, immediately after mixing the ingredients, apart from the largest influence of w/c ratio, the impact is also shown by: amount of superplasticizer (SP), a combination of w/c ratio and SP, amount of MWCNT.

Electrodeposition of Hydroxyapatite-Multiwalled Carbon Nanotube Nanocomposite on Ti6Al4V

This work aims to study the optimal conditions to synthesize hydroxyapatite-multiwalled carbon nanotube (HAp-MWCNT) coatings on Ti6Al4V by electrodeposition technique. The structural behaviors, morphology, and mechanical properties of the coatings were characterized by various advanced methods. The analyzed results showed that the obtained coatings were composed of hydroxyapatite (HAp) and multiwalled carbon nanotube (MWCNT) phases. The presence of MWCNTs in the HAp-MWCNT composite, which improved adhesion between the coatings and the substrate about 2.3 times, increased 20% of hardness and decreased about 40% the solubility of HAp-MWCNTs/Ti6Al4V in comparison with pure HAp coating on Ti6Al4V.

Functionally Decorated Carbon Nanotube Networks for Energy Storage in Supercapacitors

A novel approach has been developed for the fabrication of Fe3O4 decorated multiwalled carbon nanotubes (MWCNT) for energy storage in negative electrodes of electrochemical supercapacitors. Synthesis of Fe3O4 was performed in the presence of MWCNT, dispersed using various cationic and anionic polyaromatic dispersants. The comparison of experimental results obtained using different dispersants provided an insight into the influence of the chemical structure of the dispersant molecules on the microstructure of the Fe3O4-MWCNT materials. It was found that positively charged groups and chelating catechol ligands of the dispersants facilitated the formation of Fe3O4 decorated MWCNT with low agglomeration. The Fe3O4 -MWCNT materials, prepared using different dispersants were used for the fabrication of electrodes with mass loading of 40 mg cm-2. The highest capacitance was obtained in 0.5 M Na2SO4 electrolyte for Fe3O4 decorated MWCNT prepared using cationic celestine blue dye as a dispersant. Improved cyclic voltammery profile was obtained using FeOOH as an additive. Asymmetric devices were fabricated and tested based on the Fe3O4 decorated MWCNT negative electrodes and MnO2-MWCNT positive electrodes.

Cost-Effective Potentiometric Platforms Modified with Multi-Walled Carbon Nanotubes (MWCNTs) and Based on Imprinted Receptors for Fluvoxamine Assessment.

A simple, efficient and reliable analytical method was developed and used for the determination of the fluvoxamine drug (FLV) in pharmaceutical preparations and biological fluids. The method is based on the cost-effective screen-printed platform for the potential transduction of the drug. Host-tailored molecular imprinting polymer (MIP) was integrated with the potentiometric platform as a recognition receptor, in which FLV, acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA) and acetonitrile were used as a template, functional monomer, cross-linker, and solvent, respectively. MIP particles were dispersed in plasticized poly (vinyl chloride) (PVC) and the membrane was drop-casted on carbon screen-printed electrode. The MIP, in addition to non-imprinted polymers (NIP), was characterized and the binding experiment revealed high affinity and adsorption capacity of MIP towards FLV. The proposed sensor displayed near-Nernstian cationic slope of 55.0 ± 0.8 mV/decade (r2 = 0.999) with a low detection limit of 4.8 × 10−6 mol/L over a wide pH range (3.0–8.5). The electrochemical features of the proposed sensors including electrochemical impedance spectroscopy (EIS) and chronopotentiometry measurements (CP) in the presence of multi-walled carbon nanotubes (MWCNTs) as a solid contact transducer were also investigated. The applications of the proposed sensor for the determination of FLV in different dosage forms with recovery values (98.8%–101.9%) and (97.4%–101.1%), respectively compared with the reference HPLC method with acceptedFandt-student tests values at the 95% confidence level.

Effect of MWCNT on the Structure and Property of Nanofibrous Bundles by Blown Bubble Spinning.

Many spinning patents and technologies have been explored to produce diverse types of nanomaterials for different applications. As a novel method, the blown bubble-spinning is a one-step process for fabrication of nanofibrous bundles. In this study, polyamide6/66(PA6/66) nanofibrous bundles filled with different concentrations of multi-walled carbon nanotubes (MWCNTs) were prepared by the blown bubble-spinning. The dispersion of MWCNT in nanofibers under different treatments was investigated and a detailed characterization focusing on the influence of the presence of MWCNT on the morphology, thermal property and electrical property was carried out. The results showed that MWCNTs treated by Tween60 and ultrasonication were embedded in the PA6/66 nanofibers with uniform dispersion. In addition, it was observed that thermal stability and electrical conductivity of nanofibrous bundles increased with an increase in MWCNT content. The PA6/66/MWCNT nanofibrous bundles fabricated by the blown bubble spinning have the great potential applications in sensors and supercapacitors.

Influence of multi-walled carbon nanotubes on the microbial biomass, enzyme activity, and bacterial community structure in 2,4-dichlorophenol-contaminated sediment

The rise in manufacture and use of carbon nanotubes has aroused the concern about their potential risks associated with coexisting pollutants in the aquatic environment. 2,4-dichlorophenol (2,4-DCP), with a high toxicity to many aquatic organisms, is a widespread pollutant resulting from the extensive use of pesticides and preservatives. In this article, the adsorption of 2,4-DCP by riverine sediment and the responses of sediment microbial community to 2,4-DCP were studied in the presence of multi-walled carbon nanotubes (MWCNTs). Adding MWCNTs significantly increased the adsorption amount of sediment for 2,4-DCP from 0.541 to 1.44 mg/g as the MWCNT concentration increased from 0 to 15 mg/g. The responses of sediment microbial community were determined after one-month exposure to MWCNTs at different concentrations (0.05, 0.5, 5, and 50 mg/g). The microbial biomass carbon in the sediment contaminated with 2,4-DCP increased in the presence of 5 mg/g of MWCNTs (from 0.06 to 0.11 mg/g), but not significantly changed at other MWCNT concentrations. For the sediments contaminated with 2,4-DCP, the presence of MWCNTs made no difference to urease activity, while the dehydrogenase activity slightly increased with the addition of 5 mg/g of MWCNTs and decreased in the presence of 50 mg/g of MWCNTs. The changes of sediment bacterial communities were further determined by 16S rRNA gene sequencing. Based on the weighted UniFrac distance between communities, the clustering analysis suggested that the contamination of 2,4-DCP affected the bacterial community structure in a greater degree than that caused by MWCNTs at relatively low concentrations (≤5 mg/g). Bacteroidetes, Planctomycetes, and Nitrospirae were feature bacterial phyla to reflect the effects of MWCNTs and 2,4-DCP on sediment bacterial community. These results may contribute to the understanding of microbial community response to co-exposure of MWCNTs and 2,4-DCP and the assessment of associated ecological risks.

Synthesis of multiwall carbon nanotubes in presence of magnetic field using underwater arc discharge system

In present work, we have used the underwater arc-discharge to synthesize carbon nanotubes (CNTs). Copper rod and graphite rode are used as a cathode and anode, respectively for CNTs synthesis. In addition to the DC current of 50 amp, a perpendicular magnetic field is also applied across the electrodes while producing CNTs. The CNTs are characterized using X-ray diffraction (XRD), FTIR and RAMAN spectroscopy. We have found that the MWCNTs synthesized in the presence of both electric and magnetic field have a smaller diameter compared to conventional arc discharge method.

Aldehyde functionalized multiwalled carbon nanotubes to synthesize highly conducting polyaniline-MWNT thin films

Polyaniline (PANI) and its composites with other materials gains great attraction in the field of conducting polymers as their properties can be easily tuned to the desired level. Multiwalled Carbon nanotubes (MWNT) are such a promising material to make composites with PANI. Presence of MWNT in PANI composite enhances its conductivity and makes the composite thermally stable. But dispersivity of PANI-MWNT composite in solvents is very low while preparing thin film samples. To improve the solubility and processability of PANI-MWNT composite, MWNT has to be modified by attaching suitable functional groups to the side walls of carbon nanotubes without changing the composition of nanotubes. The functionalization of multi-walled carbon nanotubes was carried out using HCl treated MWNTs. MWNTs were reacted with formaldehyde and attached into methylol groups (–CH2OH). The presence of methylol group makes the carbon nanotubes more lyophilic than the pristine form and improves the processability of MWNTs and MWNT containing composites. Structural characterization is carried out by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. Electrical characterization of the samples were carried using standard four point probe method. Pristine MWNT shows flat temperature response of DC electrical conductivity. The room temperature conductivity of pristine MWNT, PANI and PANI-MWNT composites are 9.5 S/cm, 2.27 S/cm and 11.8 S/cm respectively. In the present work, we have achieved significant dispersivity of PANI-MWNT composites as a result of the functionalization and the thin film sample shows electrical conductivity of 565.44 S/cm which is very high for conducting polymer composites. These composites show metallic character and its temperature coefficient of resistance (α) is found to be 0.0038 °C−1, which is less than that of copper.

Melt-mixed nanocomposites of SIS/MWCNT: rheological, electrical and structural behavior

Abstract In this work, nanocomposites based on the triblock copolymer polystyrene-b-polyisoprene-b-polystyrene (SIS) thermoplastic elastomer filled with multiwall carbon nanotubes (MWCNT) were obtained by melt mixing. The nanocomposites were characterized by oscillatory rheometry, electrical resistivity, small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM). The results showed that both, rheological and electrical percolation were achieved at MWCNT loadings between 1-3 vol.%. Rheological tests revealed that the insertion of MWCNT into SIS significantly enhanced the process of relaxation of SIS blocks. Resistivity measurements revealed that conductive nanocomposites were obtained at MWCNT loadings ~1.6 vol.%. The electrical resistivity decreased eleven orders of magnitude from neat SIS to SIS/ 5 vol.% MWCNT. Finally, SAXS and TEM showed that the melt mixing process and the presence of MWCNT hampered the self-assembly of SIS into well-ordered domains.