Amount Of Multi-walled Carbon Nanotubes Research Articles

Improved shape memory effects in multiwalled‐carbon‐nano‐tube reinforced thermosetting polyurethane composites

ABSTRACTShape memory thermosetting polyurethane (SMPU) composites containing different amount of multiwalled carbon nanotube (MWCNT) ranging from 0 to 0.250 phr were prepared. The shape memory behavior, tensile stress, and recovery stress were determined by using conventional thermomechanical cycle; however, the modified thermomechanical cycle designated as progressive stretch–relax–stretch (PSRS) cycle was also employed to create shape memory effects in studied composites. The test was carried out in water bath which was equipped with an electric heater, temperature controller, and tensile stress and strain measuring setup. The recovery and tensile stresses both were showing higher values for PSRS samples as compared with conventional samples. Loading of MWCNT improved the recovery stress of SMPU, thereby confirming reinforcing effect. The maximum recovery stress of 2.17 MPa for 0.188 phr MWCNT loading was observed as compared with 1.09 MPa of unreinforced SMPU specimen. The recovery time was also improved on reinforcement as demonstrated in this article. The morphology of fractured surface and degree of dispersion of MWCNT was studied using Field Emission Scanning Electron Microscope. The impact on glass transition temperature was also observed for MWCNT reinforcement on SMPU, which depends on the degree of dispersion and loading of MWCNT in the specimen. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44389.

Photoinactivation of bacteria by using Fe-doped TiO2-MWCNTs nanocomposites

In this study, nanocomposites of Fe-doped TiO2 with multi-walled carbon nanotubes (0.1- 0.5 wt. %) were prepared by using sol-gel method. The structural and morphological analysis were carried out with using X-ray diffraction pattern and transmission electron microscopy, which confirm the presence of pure anatase phase and particle sizes in the range 15-20 nm. X-ray photoelectron spectroscopy was used to determine the surface compositions of the nanocomposites. UV-vis diffuse reflectance spectra confirm redshift in the optical absorption edge of nanocomposites with increasing amount of multi-walled carbon nanotubes. Nanocomposites show photoinactivation against gram-positive Bacillus subtilis as well as gram-negative Pseudomonas aeruginosa. Fe-TiO2-multi-walled carbon nanotubes (0.5 wt. %) nanocomposites show higher photoinactivation capability as compared with other nanocomposites. The photoluminescence study reveals that the Fe-TiO2-multi-walled carbon nanotubes nanocomposites are capable to generate higher rate of reactive oxygen species species than that of other nanocomposites. Our experimental results demonstrated that the Fe-TiO2-multi-walled carbon nanotubes nanocomposites act as efficient antibacterial agents against a wide range of microorganisms to prevent and control the persistence and spreading of bacterial infections.

Effect of Multi-wall Carbon Nanotubes(MWNTs) on Structural and Mechanical Properties of Poly(3-hydroxybutirate) Electrospun Scaffolds for Tissue Engineering Applications

The aim of this study was to improve the electrospinning parameters and evaluate the effects of Multi-Walled Carbon Nano-Tubes (MWNTs) on the structural and mechanical properties of Poly-3-hydroxybutyrate (P3HB) electrospun scaffolds. To this end, to achieve optimal properties of the electrospinning machine, P3HB polymer solutions were prepared at different concentrations and spinned. After optimization, MWNTs at different weight percentages (0.5%, 0.75%, 1% and 1.25%) were added to the polymer solutions and electrospinned. The effects of different concentrations of MWNTs on the structure of fibers and properties of the scaffolds were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Evaluation of the scaffold morphology showed the presence of MWNTs into fibers, that Adding different amounts of nanotubes increased the average diameter of the fibers,with the mean increase reaching 700 nm from 240 nm. In addition, evaluation of porosity with the use of SEM photomicrographs and the MATLAB software program showed an increase in porosity from 81% to 84% in the presence of MWNTs. The analysis of mechanical properties of the PLGA/MWNTs composites revealed 158% improvement over pure PHB scaffold, So that the tensile strength in presence of only 0.5% MWNTs increased from 2 to 5.15 MPa. According to mechanical and structural properties obtained, the best amount of MWNTs was 0.5 wt%. Therefore, it is possible to significantly improve the structural and mechanical properties of pure P3HB scaffolds by incorporating some MWNTs to their structure so that they can become favorable for tissue engineering applications.

Combined effect of carbon nanotubes and polypyrrole on the electrical properties of cellulose-nanopaper

In the present study, 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (CNF) were combined with multi-walled carbon nanotubes (MWCNTs) and with hybrid MWCNT/polypyrrole to produce a variety of binary and ternary formulations of conductive nanopapers. By following a simple mixing/sonication/filtering process, a homogeneous and well-distributed CNF-MWCNT nanostructure was formed, resulting in a nanopaper of strong mechanical properties (141 MPa tensile strength and 9.41 GPa Young’s modulus) and good electrical conductivity (0.78 S cm−1), for the formulation with 50 wt% of MWCNT. The subsequent in situ polymerization of pyrrole in CNF-MWCNT mixtures produced ternary multiphase CNF-MWCNT-PPy nanopapers with much improved electrical conductivity (2.41 S cm−1) and electrochemical properties (113 F g−1 specific capacitance), even using little amounts of MWCNTs. With these materials, improved hybrid capacitors can be designed. The article presents a trend for the application of cellulose nanofibers in the field of green and flexible electronics.

Electrochemical determination of food colorants in soft drinks using MWCNT-modified GCEs

Food colorants are chemicals added to foods and soft drinks during manufacturing or processing. However, some of these chemicals represent potential risks to human health, especially if they are consumed in excess. Here, we modified a glassy carbon electrode (GCE) with multi-walled carbon nanotubes (MWCNTs) using 1,3-dioxolane as a dispersant agent, resulting in a stable and reproducible electrochemical sensor. The resulting sensor was applied to study the food dyes tartrazine, sunset yellow and carmoisine, showing high sensitivity and reproducibility. The influences of the scan rate, pH, amount of MWCNTs and accumulation time were studied. Moreover, the developed method was successfully applied in the determination of colorants in commercial soft drinks and compared with a chromatographic method. The resulting concentrations were compared based on the maximum amount of soft drink that a child and an adult can consume before reaching the admissible daily intake (ADI) of each colorant.

AOT assisted preparation of ordered, conducting and dispersible core-shell nanostructured polythiophene – MWCNT nanocomposites

Abstract Core-shell nanostructured polythiophene-multiwalled carbon nanotube nanocomposites (PT-CNTs) have been synthesised by in-situ chemical oxidative polymerization of thiophene in presence of multiwalled carbon nanotubes (MWCNT) and anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) using ferric chloride as an oxidizing agent in chloroform solution. Nanocomposites were prepared by introducing different weight percentage amount of MWCNT into a fixed monomer and surfactant composition. The formations of the polythiophene-multiwalled carbon nanotube nanocomposites have been characterised by fourier transform infrared spectroscopy and elemental analysis. Sodium bis(2-ethylhexyl) sulfosuccinate (AOT) has been used as dopant cum template for polythiophene and polythiophene-multiwalled nanocomposite preparation. WXRD studies reveal that polythiophene shows a broad peak at 2θ value 18.23°. On the other hand, PTCNT nanocomposites were shown a sharp peak at 2θ value 26.48° and the broad peak present in polythiophene was completely vanished upon nanocomposite formation. The scanning electron microscopic (SEM) analysis of the samples reveals that PTCNT nanocomposites have a fiber like nanostructures. The core-shell nanostructure formation was confirmed by transmission electron microscopy (TEM) analysis. The outer shell thickness of the carbon nanotubes in nanocomposite increases approximately 3 to 15 nm from the original thickness after the formation of nanocomposite. The PTCNT samples synthesised in presence of AOT were easily dispersed in chloroform, which enabled us to carry out the UV–Visible absorption spectroscopy. The characteristic absorption peak present at 340 nm corresponds to the π-polaron transition of polythiophene. The formation mechanism of core-shell nano structured composites was proposed based on the evidence from SEM, TEM, WXRD and spectroscopic studies. The four probe electrical conductivities of PTCNT samples were of the order of 1.5 times higher in magnitude than PT samples.

Preparation of Multi-Walled Carbon Nano-Tube Composite Copper Plating from Acidic Solution

Copper has excellent thermal properties including thermal conductivity; therefore copper has been used as the thermal heat dissipation materials. However, the materials with more excellent thermal properties are needed for the increasing of the packaging density of electronic equipment. The authors have focused on the excellent thermal properties of Multi-Walled Carbon Nano-Tube (MWCNT). MWCNT has excellent thermal properties, mechanical properties and electrical properties, then, it is expected to be applied to various fields such as electronic component, semiconductor, medical, biotechnology and so on. It was considered that the thermal properties of the copper plating could be greatly improved by compositing MWCNT with copper plating. The purpose of this study is to prepare MWCNT composite copper plating with more excellent thermal properties than conventional copper plating. MWCNT composite copper plating was obtained from the copper sulfate bath with suspended MWCNT by general electrolytic method. Various plating conditions had been investigated in order to increase the content of MWCNT in the films such as the concentration of MWCNT and pH of the plating baths, surfactant, current density, film thickness and agitation speed were researched. The content of MWCNT in the films was measured by combusting the samples in oxygen atmosphere and measuring amount of generated gas, CO and CO2, by infrared absorption method. There were optimal conditions for preparing the composite copper plating with higher amount of MWCNT. It should be noted, that the higher amount of MWCNT in the films increased the thermal conductivity of the films, but that the using additives for MWCNT dispersion reduces the thermal conductivity comparing to the copper plating without additives by the thermal conductivity measurement. Then the authors also focused on the hydrothermal treatment to MWCNT in various acidic solutions as a method that used no additives. It was effective for improvement of the amount of MWCNT in the films. The samples containing the largest amount of MWCNT was prepared when using MWCNT treated in mixed acid of sulfuric acid and nitric acid at the ratio of 3 to 1 at 150 °C for 2 hours. The MWCNT content in the copper film was 1.01 mass%, which was maximum value in this study. The sample which was prepared using hydrothermal treated MWCNT, without using addition agent, had slightly higher thermal conductivity than that of the conventional copper plating without additives.

Multiwalled Carbon Nanotubes (MWCNTs) as Ignition Agents for Air/Methane Mixtures

The possibility to ignite the single wall carbon nanotubes (SWCNTs) once exposed to the radiation of a flash camera, was observed for the first time in 2002. Subsequently, it was proposed to exploit this property in order to use nanostructured materials as ignition agents for fuel mixtures. Lastly, in 2011, it was shown that SWCNTs can be effectively used as ignition source for an air/ethylene mixture filling a constant volume combustion chamber; the observed combustion presented the characteristics of a homogeneous-like combustion. In the presented experimental activity, the potentiality of igniting an air/methane mixture by flashing multiwall carbon nanotubes (MWCNTs) has been exploited, and the results compared with those obtained igniting the mixture with a traditional spark plug. In detail, two types of tests have been carried out: the first, aiming at comparing the combustion process flashing a variable amount of nanoparticles introduced into the combustion chamber at fixed air/methane ratio; the second, at comparing the combustion process with the one obtained using a traditional engine spark plug, varying the air/methane ratio and at fixed amount of MWCNTs. During tests, the combustion process has been characterized measuring the pressure into the combustion chamber as well as acquiring images with a high-speed camera. The results confirm that the ignition triggered with MWCNTs leads to a faster combustion, without observing a well-defined flame front propagation, observed, as expected, with the spark assisted ignition. Moreover, dynamic pressure measurements show that the MWCNTs photo-ignition determines a more rapid pressure gradient and a higher heat release rate compared to spark assisted ignition.

Clay‐Graphene Nanoplatelets Functional Conducting Composites

An approach to functionalize graphene‐based materials has been developed by assembling graphene nanoplatelets (GNP) with clay minerals. Under convenient sonomechanical treatment, clay–GNP mixtures may produce very stable water dispersions in particular using sepiolite fibrous clay. While in the absence of clay a rapid decantation of GNP in water is observed, in the presence of sepiolite the resulting dispersions remain stable during months without syneresis effects. Rigid but flexible self‐supported films are easily obtained by filtering of these dispersions. As the electrical percolation threshold corresponds to sepiolite/GNP composites of 0.5:1 in weight, doping these systems with multiwalled carbon nanotubes (MWCNTs) significantly enhances their electrical conductivity. The particular microporosity of the sepiolite component allows interactions with molecules, such as organic dyes, as well as polymers, such as biopolymers, opening the way to functional materials for advanced applications due to their inherent conductivity afforded by the GNP and MWCNTs carbonaceous components. In fact, using very small amount of MWCNT together with GNP can obtain composites with significant electrical conductivity, maintaining the enhanced mechanical properties, at a lower cost.

Moisture-sensitive properties of multi-walled carbon nanotubes/polyvinyl alcohol nanofibers prepared by electrospinning electrostatically modified method

Polyvinyl alcohol (PVA) nanofibers reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated by electrospinning. MWCNTs were introduced into the PVA matrix through the application of an electric field. The morphology of the composite MWCNTs/PVA fibers was characterized by scanning electron microscopy. Results show that the nanofibers had a diameter between 48 and 103nm and contained a variable amount of MWCNTs. The electrical properties of MWCNTs/PVA nanofibers were investigated by fabricating impedance-type sensors. The impedance and electrical conductivity of the samples were evaluated in the range 46% and 89% relative humidity.

The effects of carbon nanotubes, blend composition and glycidyl methacrylate-grafted polypropylene compatibilizer on the morphology, mechanical and electrical properties of polypropylene-polyamide 6 blends

The effect of multi-walled carbon nanotubes (MWCNTs) and a glycidyl methacrylate grafted polypropylene (PP-g-GMA) on the morphology, electrical and mechanical properties of polypropylene (PP), polyamide 6 (PA6) and their respective blends (PP/PA6), prepared by melt mixing, was investigated. The study of MWCNT nanocomposites from PP/PA6 blends is of significant interest, given that they combine the thermomechanical properties of PA6 with the processability of PP, resulting in materials with a wide range of mechanical and electrical properties. In this work, it was demonstrated that the addition of the same amount of MWCNTs to immiscible PP/PA6 blends produced nanocomposites with different morphologies, mechanical and electrical properties depending on the polymer proportion, and that the PP-g-GMA improved mechanical properties while preserving the electrical properties. SEM and TEM images showed that MWCNTs were comparatively better dispersed in PA6 than in PP; however, the addition of PP-g-GMA to PP matrix improved MWCNT dispersion. On the other hand, SEM micrographs showed different morphologies of PP/PA6 blends, depending on the composition of the polymers in the blend. The addition of PP-g-GMA to PP/PA6 blends and PP/PA6/MWCNT nanocomposites reduced significantly the domain size in both dispersed and continuous phases. Regardless of compatibilization, MWCNTs were located preferentially in the PA6 phase. The electrical characterization showed that PP/PA6/MWCNT nanocomposites exhibited lower volume resistivity values (108 Ω cm) compared to PA6/MWCNT nanocomposites (1011 Ω cm), at the carbon nanotube load employed, as a result of the confinement of the MWCNTs in the PA6 phase. The incorporation of PP-g-GMA to the PP/PA6 blends and PP/PA6/MWCNT nanocomposites did not cause a significant change in the volume resistivity of the blends; moreover, PP-g-GMA considerably improved the modulus and tensile strength of the PP/PA blends (i.e. up to 90 and 97 %, respectively for PP/PA 80/20 blend).

Microstructure, mechanical, and rheological properties of natural rubber/ethylene propylene diene monomer nanocomposites reinforced by multi‐wall carbon nanotubes

Nanocomposites based on natural rubber (NR)/ethylene propylene diene monomer (EPDM)/multi‐wall carbon nanotubes (MWCNT) have been prepared in an internal and a two roll‐mill mixer in two steps. The effect of carbon nanotubes (MWCNTs) and rubber composition were studied on microstructure, mechanical and rheological properties of the vulcanizated NR/EPDM/MWCNT nanocomposites. Ethylene propylene diene monomer grafted with maleic anhydride (EPDM‐g‐MAH) was prepared using a solution process. Grafting of maleic anhydride on EPDM confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR). The effects of compatibilizer (EPDM‐g‐MAH) and functionalized carbon nanotubes (f‐MWCNTs) on mechanical properties of NR/EPDM/MWCNT nanocomposites was investigated as well. Dynamic mechanical thermal analysis (DMTA) results demonstrated the glass transition temperature (Tg) of nanocomposites were slowly enhanced with increasing the amount of MWCNTs. The microstructure of nanocomposites have been characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which showed that the observed MWCNTs were in both NR and EPDM phases. The rheological behavior has been evaluated by a rubber processing analyzer (RPA). The ozone resistance times of the nanocomposite samples indicated that by increasing the amount of MWCNTs ozone resistance was improved. POLYM. COMPOS., 39:E745–E753, 2018. © 2016 Society of Plastics Engineers

Mechanical properties, thermal behaviors and oil resistance of epoxidized natural rubber/multiwalled carbon nanotube nanocomposites prepared via in situ epoxidation

Epoxidized natural rubber (ENR)/multiwalled carbon nanotube (MWCNT) nanocomposites were prepared via in situ epoxidation of natural rubber (NR) using a molar ratio of formic acid/hydrogen peroxide to isoprene unit at 0.75/0.75 with five loadings of MWCNTs, ranging from 0.5–2.5 parts per hundred parts of rubber (phr), at 50°C for 4 h. Based on Fourier transform infrared spectra, the epoxide content of ENR in the nanocomposites was about 32.5–33.2 mole%. Accordingly, the products were referred to ENR30/MWCNT nanocomposites. The curing characteristics, mechanical properties (tensile properties, tear strength, and hardness), glass transition temperature ( Tg), thermal stability, and oil resistance of these in situ ENR30/MWCNT nanocomposites were investigated and compared with NR and neat ENR30. The results showed that the scorch and cure times of ENR30/MWCNT nanocomposites were the longest followed by NR and ENR30. The incorporation of an appropriate amount of MWCNTs into the in situ epoxidation apparently improved the properties of NR. Among them, the nanocomposites filled with 2 phr MWCNTs exhibited the highest mechanical properties, Tg, thermal stability, and oil resistance. The mechanical properties of the in situ nanocomposites were also compared with those of the control nanocomposites prepared by adding MWCNTs directly in the prepared ENR30 latex. It was found that at similar MWCNT loadings, the in situ nanocomposites exhibited higher mechanical properties than the control nanocomposites.

Bioaccumulation of Multiwall Carbon Nanotubes in Tetrahymena thermophila by Direct Feeding or Trophic Transfer.

Consumer goods contain multiwall carbon nanotubes (MWCNTs) that could be released during product life cycles into the environment, where their effects are uncertain. Here, we assessed MWCNT bioaccumulation in the protozoan Tetrahymena thermophila via trophic transfer from bacterial prey (Pseudomonas aeruginosa) versus direct uptake from growth media. The experiments were conducted using (14)C-labeled MWCNT ((14)C-MWCNT) doses at or below 1 mg/L, which proved subtoxic since there were no adverse effects on the growth of the test organisms. A novel contribution of this study was the demonstration of the ability to quantify MWCNT bioaccumulation at low (sub μg/kg) concentrations accomplished by employing accelerator mass spectrometry (AMS). After the treatments with MWCNTs at nominal concentrations of 0.01 mg/L and 1 mg/L, P. aeruginosa adsorbed considerable amounts of MWCNTs: (0.18 ± 0.04) μg/mg and (21.9 ± 4.2) μg/mg bacterial dry mass, respectively. At the administered MWCNT dose of 0.3 mg/L, T. thermophila accumulated up to (0.86 ± 0.3) μg/mg and (3.4 ± 1.1) μg/mg dry mass by trophic transfer and direct uptake, respectively. Although MWCNTs did not biomagnify in the microbial food chain, MWCNTs bioaccumulated in the protozoan populations regardless of the feeding regime, which could make MWCNTs bioavailable for organisms at higher trophic levels.

Synergistic effect of multiwalled carbon nanotubes and carbon black on rheological behaviors and electrical conductivity of hybrid polypropylene nanocomposites

The monograph, electrical conductivity, and rheological behaviors of isotactic polypropylene /carbon black (CB)/multiwalled carbon nanotubes (MWCNTs) composites were studied. Ternary composites including MWCNTs and CB revealed an electrical property similar to the binary MWCNTs composites. This work showed that a synergistic effect result in preserved electrical behavior with a simultaneous effective reduced of the MWCNTs amount. Moreover, the combination of conductive fillers also resulted in a decreased rheological percolation threshold, an accelerated formation of rheological network and a delay in the destruction of the filler network. The similar value of the activation energy for CB/MWCNTs and MWCNTs verified the existence of a co‐supporting networked formed by MWCNTs and CB. Two strain‐softening processes are found in a strain sweep for the ternary composite melt with high filler loading. The low‐strain‐softening process may be an indication that the MWCNTs filler network is broken into separated aggregated structures, while the high‐strain‐softening process should be related to the breakdown of the temporary network structure. POLYM. COMPOS., 39:E723–E732, 2018. © 2016 Society of Plastics Engineers

Enhanced performance of immobilized laccase in electrospun fibrous membranes by carbon nanotubes modification and its application for bisphenol A removal from water

Multi-walled carbon nanotubes (MWCNTs) were used as modified materials to improve the performance of laccase-carrying electrospun fibrous membranes (LCEFMs). The MWCNTs modified LCEFMs (MWCNTs-LCEFMs) were successfully fabricated via emulsion electrospinning, with active laccase and MWCNTs encapsulated inside the fibers. After modified by an optimal amount (1.5wt%, vs. polymer) of MWCNTs, the obtained MWCNTs-LCEFMs showed not only higher activity recovery (85.3%, vs. free laccase) than LCEFMs (71.2%), but also better storage and operational stability, which were mainly attributed to the promoted electron transfer in laccase-catalytic reaction. Furthermore, the specific surface area and tensile strength of MWCNTs-LCEFMs have also been enhanced nearly 2 and 3 times than those of LCEFMs, respectively. The MWCNTs-LCEFMs were applied to remove the widespread bisphenol A from water, where their removal efficiency reached above 90%, with the degradation efficiency accounting for over 80%, and their adsorption efficiency increased about 45% than that of LCEFMs. In addition, the endurances of MWCNTs-LCEFMs to environmental factors such as pH and temperature were also improved.

Mechanical Properties and Durability of Ultra High Strength Concrete Incorporating Multi-Walled Carbon Nanotubes.

In this work, the effect of the addition of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and durability of ultra high strength concrete (UHSC) is reported. First, the MWCNTs were dispersed by a nano sand-mill in the presence of a surfactant in water. The UHSC specimens were prepared with various amounts of MWCNTs, ranging from 0% to 0.15% by weight of cement (bwoc). Results indicated that use of an optimal percentage of MWCNTs (0.05% bwoc) caused a 4.63% increase in compressive strength and a 24.0% decrease in chloride diffusion coefficient of UHSC at 28 days curing. Moreover, the addition of MWCNTs also improved the flexural strength and deformation ability. Furthermore, a field-emission scanning electron microscopy (FE-SEM) was used to observe the dispersion of MWCNTs in the cement matrix and morphology of the hardened cement paste containing MWCNTs. FE-SEM observation revealed that MWCNTs were well dispersed in the matrix and no agglomerate was found and the reinforcing effect of MWCNTs on UHSC was thought to be pulling out and microcrack bridging of MWCNTs, which transferred the load in tension.

Enhancement of the ferroelectricity of poly(vinylidene fluoride)/multiwalled carbon nanotube composite scaffolds and its effect on the cellular metabolic activity

Abstract The highly polar surfaces having a strong effect on the cellular growth are desirable for the preparation of effective scaffolds. Here, we demonstrate that poly(vinylidene fluoride) (PVDF)/multiwalled carbon nanotube (MWCNT) composite films having a very high β-phase that shows the ferroelectric properties are quite effective for cell growth of RT4-D6P2T cells (Schwannoma cell line of rats), U87-MG (glioblastoma cell line of human) and SH-SY5Y (neuroblastoma cell line of human) cells. The contents of polar β-phase in the nanocomposite films could be finely tuned by the variation of MWCNT amount. The cell growth behavior of the three types of cells was congruent with the amount of the polar β-phase. Addition of 0.5 wt% MWCNT could generate 10% more β-phase in the composite, but show 250% more cell proliferation rates for all three cells than neat PVDF film after 7days of incubation. In vitro tests revealed synergy effects of scaffold’s stiffness and ferroelectricity on the cellular activity with the amount of MWCNT in the composite film.

Carbon nanotube reinforced alkali-activated slag mortars

The paper reports on a study of the effect of multi-walled carbon nanotubes (MWCNTs) when used as dispersed reinforcement on the fracture properties and microstructure of alkali-activated slag mortars. The amount of MWCNTs added varied in the range of 0.05–1.0% of the mass of slag. Mechanical and fracture properties were determined using fracture tests carried out on 40×40×160mm specimens with a central notch. The observed parameters were compressive strength, modulus of elasticity, effective fracture toughness and specific fracture energy. Specimen response during fracture tests was also monitored by means of acoustic emission, and this method was also used for the determination of cracking tendency due to autogenous and drying shrinkage occurring during the hardening process. It is shown that the addition of up to 0.2% of MWCNTs improves the fracture properties of alkali-activated slag. Although a higher dosage of MWCNTs reduced the number of microcracks observed by acoustic emission, the mechanical properties of the slag deteriorated due to the less effective dispersion of the MWCNTs and the formation of bundles.

Effect of MWNTs-addition on cathodic performance of Ti-V-Ni composites for Ni-MH batteries

Composites of Ti1.4V0.6Ni alloy and various amounts of multiwalled carbon nanotubes (MWNTs) have been synthesized by high energy mechanical ball-milling method. The composites mainly contain icosahedral quasicrystal and TiNi-type phases. In contrast to Ti1.4V0.6Ni, all milled composites have excellent activation properties activated at the first charge/discharge cycle, together with excellent rate discharge abilities. The composites are able to deliver outstanding maximum discharge capacities of 295.5 mAh g−1 enhanced by 68.2 mAh g−1 in comparison to Ti1.4V0.6Ni alloy, and good cycling stabilities with capacity retention of more than 40% after 100 charge/discharge cycles higher than Ti1.4V0.6Ni alloy. Experimental and theoretical investigations suggest that the unusual electrochemical performance of this composite is depended on the copacetic electrocatalytic activity of MWNTs addition and the enhancement of hydrogen diffusion progress.