Properties Of Multi-walled Carbon Research Articles

Preparation and Properties of Multiwalled Carbon Nanotube/Waterborne Polyurethane Superhydrophobic Conductive Coatings Using Electrostatic Spraying

Preparation and Properties of Multiwalled Carbon Nanotube/Waterborne Polyurethane Superhydrophobic Conductive Coatings Using Electrostatic Spraying

Structure and Properties of Multi-walled Carbon Nanotube/Acrylonitrile Butadiene Styrene Nanocomposite Specimens Prepared by Fused Deposition Modeling

Acrylonitrile butadiene styrene (ABS) nanocomposites reinforced with multi-walled carbon nanotubes (MWCNTs) were prepared by melt blending and then extruded in filaments for the fused deposition modeling (FDM) process. The structure and properties of the FDM printed specimens were investigated by scanning electron microscopy, Raman spectroscopy, tensile testing, and dynamic mechanical analysis. The results showed that MWCNTs were evenly dispersed in the styrene-acrylonitrile (SAN) phase of the ABS matrix and had strong interactions with the SAN, which resulted in improvements of the tensile strength and modulus of the printed specimens. The tensile strength and modulus of the specimen with 8 wt.% MWCNTs reached 52.1 and 2727.2 MPa, which was 29% and 40% higher than those of the ABS specimens, respectively. Furthermore, the addition of MWCNTs improved the storage modulus (E′), glass transition temperature (Tg) and the thermal stability properties of the ABS specimens.

Effect of coating process on the properties of multi-walled carbon nanotubes/waterborne polyurethane anticorrosive and conductive coating

A thicker layer of multi-walled carbon nanotubes (MWCNTs)/waterborne polyurethane (WPU) anticorrosive and conductive coating was respectively prepared on the Q235 steel substrate by brushing (Br) and electrostatic spraying (ES) in this work. The effect of coating process on the dispersion of the MWCNTs and the electrical conductivity, corrosion resistance, and bond strength of the coating was investigated. It was shown that the coating prepared by ES (ES coating) had a smooth surface, few defects and evenly dispersed MWCNTs. The coating prepared by Br (Br coating) had a rough surface, some defects and obviously agglomerated MWCNTs. The electrical conductivity, corrosion resistance, and bond strength of the ES coating were higher than those of the Br coating with the same MWCNT content. As the MWCNT content increased, the electrical conductivity of the ES coating increased, however, its corrosion resistance and bond strength first increased and then decreased. The resistivity of ES 0.3 wt% MWCNTs/WPU coating (12808.4 Ω·m) met the standard requirement of the conductive coating. Its corrosion rate was 3.50×10-5 mm/a immersed in 3.5 wt% NaCl solution. Its bond strength to the Q235 steel substrate was higher than that of ES pure WPU coating. As the MWCNT content increased, the electrical conductivity of the Br coating increased, however, its corrosion resistance and bond strength decreased. When the MWCNT content was 0.6 wt%, the Br coating would conduct electricity. Its corrosion rate was 5.24×10-2 mm/a.

Modeling creep behavior of carbon nanotube/fiber/polymer composite cylinders

In this research, the effects of multi-walled carbon nanotubes on the distribution of long-term creep strains in thick-walled multi-walled carbon nanotube/fiber/polymer three-phase laminated composites are studied. In the first step, micromechanical models are developed to calculate the elastic properties of multi-walled carbon nanotube/vinylester and multi-walled carbon nanotube/E-glass fiber/vinylester composites. Using classical lamination plate theory, equilibrium and compatibility equations and strain–displacement relations, the distribution of effective stresses is considered. Moreover, utilizing Schapery single-integral model for nonlinear viscoelastic materials, Prandtl–Reuss relations and Mendelson’s approximation method, not only the distribution of circumferential and radial strains is investigated but also the effects of fiber orientation and weight fraction (wt.%) of the multi-walled carbon nanotubes on the way of distribution are studied. The results demonstrated that the addition of the multi-walled carbon nanotube to the vinylester can reduce absolute values of the radial and circumferential creep strains and dimensionless effective stresses. Moreover, most reduction occurred in the inner wall of the cylindrical shell when fiber orientation was α = 90°.

Effect of black ink loading on the properties of multi-walled carbon nanotubes/glass fibre/epoxy laminated hybrid composites

The demand for weight reduction is driven by the demand for better fuel efficiency and reduction of emissions. Polymer composites can offer lightweight benefits from 15 to 25% for glass fibre-reinforced composites in comparison to other metallic structure. Modification has been made to the fibre and polymer matrix by integrating with nanofiller, for example, multi-walled carbon nanotubes (MWCNT). In the present study, commercial black ink was utilized as dispersing agent to disperse pristine MWCNT in deionized water. The MWCNT solution was applied to the 3-ply glass fibre (GF)/epoxy using spreading method. The amount of MWCNT was fixed at 1.4 vol% whereas the black ink loading was varied from 1.4 to 5.6 vol%. The results of hybrid composites (3-ply MWCNT/GF/epoxy) were compared with 3-ply and 4-py GF/epoxy laminated composites (3GF and 4GF). It was found that about 100 and 14% improvement in flexural strength and modulus were observed for hybrid composites compared to 4GF, respectively. The storage modulus also increased up to 50% compared to 4GF. The superior properties of hybrid composites was attributed to the less MWCNT agglomerations occur during the fabrication process hence results in a good dispersion of MWCNT fillers on the fibres. This indicates that addition of MWCNT in the glass fibre laminates with the aid of black ink is able to reduce the number of glass fibre laminate and hence reduce the weight of the composite structure.

Improving mechanical properties of multi-walled carbon nanotube/epoxy composites through a simple stretch-drawing method

Horizontally aligned multi-walled carbon nanotube (CNT) sheets were produced from vertically aligned CNT arrays using drawing and winding techniques. Composites based on epoxy resin and an aligned 100-ply CNT sheet have been developed using hot-melt prepreg processing. However, wavy and poor-packed CNTs in the sheets have limited reinforcement efficiency of the CNTs in the composites. In this study, a new simple stretch-drawing method was used to modify the structures of the aligned CNT sheets for improving the composite properties. The stretch-drawing of the CNT sheets enhanced the composite properties considerably. The improved properties of the composites originated from straightening of the wavy CNTs and increasing the CNT dense packing in the composites. With a 3% stretch ratio, the aligned CNT/epoxy composites achieved their best mechanical properties in this study. The 3% stretched composites exhibit increased tensile strength by 113% and enhanced elastic modulus by 34% compared to non-stretched ones. Results show that the simple stretch-drawing is effective to produce highly aligned CNT sheets for the development of high-performance CNT composites. Compared to our previous stretching method, the stretch-drawing method in this study is more effective in improving the mechanical properties of aligned CNT/epoxy composites.

Strong increase of the dielectric response of carbon nanotube/poly(vinylidene fluoride) composites induced by carbon nanotube type and pre-treatment

Abstract The dielectric properties of multi walled carbon nanotube/poly(vinylidene fluoride) (CNT/PVDF) composites show large variations with carbon nanotube (CNT) type and fillers treatment during composite preparation. A preparation method involving toluene dispersion and corona discharge treatment has been developed allowing to obtain a maximum dielectric constant above 3000 and dielectric losses around 2.8 in a CNT/PVDF composite with 0.0419 CNT volume fraction. The electrical conductivity and dielectric response increase with CNT concentration within the composite with a strong variation around the percolation threshold. The main mechanism responsible for the large value of the dielectric constant is related to the preparation method, leading to an increase of the percolation threshold through the formation of a network of capacitors and resistors randomly connected in series and parallel. It is shown that the toluene and corona discharge methods decrease the electrical conductivity of the CNT/PVDF composite, increasing the dielectric response.

Effect of Different Hybrid Method on Properties of Carbon Nanotubes/Dolomite Hybrid Filled Phenolic Composites

Hybridization of multi wall carbon nanotubes (MWCNTs) with other filler in polymer matrix composites (PMC) is one of the techniques for combining different properties of fillers for making more unique composites. In this work, the hybrid filler (CNTs–dolomite) are prepared via chemical vapour deposition (CVD hybrid) and the milling method (physically hybrid). The effect of different hybrid method on properties of multi wall carbon nanotubes/dolomite hybrid filled phenolic composites were studied. Phenolic/CVD hybrid composites and phenolic/physically hybrid composites with different filler loadings were prepared using hot mounting press. The prepared samples were characterized for their thermal conductivity and hardness. The thermal conductivity was measured using the Transient Plane Source (TPS) method, using a Hot-DiskTM Thermal Constant Analyzer and the hardness was measured using Rockwell micro-hardness. The results showed that at 5% filler loading, the phenolic/CVD hybrid composites were capable of increasing the thermal conductivity and micro-hardness up to 7.22% and 101.6% respectively compared to pure phenolic.

Preparation, Solubility, and Electrical Properties of Multiwalled Carbon Nanotubes/Poly(1-vinyl-1,2,4-triazole) Composites via in situ Functionalization

The chemically modified multiwalled carbon nanotubes (MWCNT)/poly(1-vinyl-1,2,4-triazole) (PVTri) composites were prepared via in situ emulsion polymerization. The morphological and structural properties of the surface-modified MWCNT and the synthesized MWCNT/PVTri composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrical properties of the composite material were analyzed by conductivity measurements. The thermal analysis and the Tg value of the polymer were determined by differential scanning calorimetry technique. The obtained novel MWCNT/PVTri composites exhibited excellent solubility and possessed a slightly higher glass transition temperature than that of the pure polymer.

Effect of carbon nanotubes shape on the properties of multiwall carbon nanotubes/polyethylene flexible transparent conductive films

Transparent conductive material is used in a wide range of applications and is particularly interesting. In the present work, a series of multiwall carbon nanotubes/low density polyethylene nanocomposites with different carbon nanotubes were prepared via solution casting method. The optical transparency, morphology, and resistivity of transparent conductive films have been characterized by using UV–Vis Spectrophotometer, Field emission scanning electron microscope and Multimeter, respectively. Their electrically conductive and optically transparent properties were studied and compared. The result showed that thinner and longer multiwall carbon nanotubes were more suitable for the fabrication of flexible transparent conductive nanocomposites. The sample filled with 1 wt% of T.1 (outside diameter <8 nm, length 10–30 μm) had good transparent conductive properties (volume conductivity of 3.12 × 10−3 S m−1 and optical transmittance of 62.8 % at the light wavelength of 600 nm). The high volume conductivity and optical transparency demonstrated that such kind of nanocomposite films had favorable potential in the applications from electromagnetic interference shielding to transparent electrodes.

Enhanced electrical properties of multiwalled carbon nanotube/poly(vinylidenefluoride) films through a rolling process

Poly(vinylidene fluoride) (PVDF) films containing multiwalled carbon nanotubes (MWCNTs) were prepared by solution casting method, followed by a rolling process. With the presence of MWCNTs (up to 0.3 wt%), the influence of rolling process on the crystal structure and the electrical properties of PVDF was studied. It is shown that rolling can induce phase transition as well as increase in the crystallinity of PVDF, leading to enhancement of ferroelectric and dielectric properties. In addition, MWCNTs may promote the phase transition of PVDF, while impeding the increase of crystallinity during the rolling process. With a higher breakdown field and a lower coercive electric field in comparison with the original films, the rolled films can be efficiently poled to obtain good piezoelectricity. Moreover, with the presence of MWCNTs, electric field-induced changes in crystallinity can be obviously observed in the poled MWCNTs/PVDF films. With the highest crystallinity of β-phase, the rolled films containing 0.075 wt% MWCNTs possess the highest piezoelectric coefficient d33 of ~33 pC/N while that of pure PVDF films is only ~22 pC/N.

Characterization and Investigation of Magnetic and Microwave Properties of Multiwalled Carbon Nanotube/SrFe10MnSn0.5Ti0.5O19 Nanocomposites

SrFe10MnSn0.5Ti0.5O19/multiwalled carbon nanotube (MWCNT) nanocomposites with different volume percentages of MWCNT content were synthesized by a sol–gel method. The results of x-ray diffraction, field-emission scanning electron microscopy, and Fourier-transform infrared spectrometry analyses demonstrated that the SrFe10MnSn0.5Ti0.5O19 nanoparticles were attached on the external surfaces of the MWCNTs. Mossbauer spectroscopy indicates that the substituted cations preferentially occupy the 12k sites. Magnetic properties were measured using a vibrating-sample magnetometer, and microwave absorption properties were investigated using a vector network analyzer. It was found that, with increasing volume percentage of MWCNT content, the saturation magnetization as well as the coercivity decrease, but the reflection loss widely increases. To investigate the effect of sample thickness on the absorption properties, different values of thickness (1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, and 2 mm) were selected. The results showed that, with increasing thickness of the absorber, the reflection loss and bandwidth broadly increase.

Microwave absorption properties of rare metal-doped multi-walled carbon nanotube/polyvinyl chloride composites

Using rare metal nitrate-doped multi-walled carbon nanotubes as the absorber and polyvinyl chloride as the matrix, the microwave electromagnetic and absorbing properties of multi-walled carbon nanotube/polyvinyl chloride composites were studied. The complex permittivity of the composites doped with different rare metal nitrate decreased in the frequency region of 8.2–12.4 GHz. The minimum reflection loss of rare metal nitrate-doped multi-walled carbon nanotube/polyvinyl chloride composites decreased and shifted slightly to the higher frequency region, and the absorption bandwidth (&lt;−10 dB or &gt;90%) increased in the frequency range of 8–18 GHz compared to multi-walled carbon nanotube/polyvinyl chloride composites. The reflection loss (&lt;−10 dB) of 0.2 wt% La(NO3)3-doped multi-walled carbon nanotube/polyvinyl chloride composites is the widest from the absorption bandwidth (maximum is 5.12 GHz).

Preparation and properties of multi-walled carbon nanotube/poly(organophosphazene) composites

Carbon nanotubes (CNTs) are promising materials because of their unique properties. However, the poor solubility in solvents limits the function of CNTs and hinders their applications in many fields. Surface modification of CNTs with polymers is an efficient method to solve this problem. Several polymers were tested for the preparation of CNT dispersions. In comparison with organic polymers, poly(organophosphazenes) are highly stable macromolecules with adjustable properties which depend on the side groups. This article is to describe the synthesis of thermally stable and soluble multi-walled CNT/poly(organophosphazene) composites. The poly(organophosphazene)s substituted with (a) 100 % quaternary protonated pyridinoxy (PPY), (b) 50 % quaternary protonated pyridinoxy and 50 % a long aliphatic chain alcohol (1-dodecanol) (PDK), and (c) 50 % quaternary protonated pyridinoxy and 50 % a glycol ether [(2-(2-methoxyethoxy)ethanol] (PET) have been synthesized. f-MWCNT/poly(organophosphazene) composites have been prepared by the treatment of the functionalized multi-walled carbon nanotubes (f-MWCNT) with the protonated polyphosphazenes (PPY, PDK, and PET) using different feed ratios [Rfeed = 1:1, 1:3, 1:5, 1:10 (w:w)]. The thermal stability of prepared composites (f-MWCNT/PPY, f-MWCNT/PDK, and f-MWCNT/PET) have been investigated by TGA. By considering thermal stabilities and solubility of all prepared composites, f-MWCNT/PPY1:5, f-MWCNT/PDK1:5, and f-MWCNT/PET1:5 have been chosen as optimum composite composition and characterized by 31P NMR, 1H NMR, XRD, Raman spectroscopy, and EDX analysis. The morphologic characterizations of the f-MWCNT/PPY1:5, f-MWCNT/PDK1:5, f-MWCNT/PET1:5 nanocomposites have been carried out by HRTEM. Excellent dispersions of the nanocomposites in water and common organic solvents have been achieved. The solubility and thermal stability of nanocomposites depend on the side groups on poly(organophosphazene).

Preparation and Luminescence Property of Multi-Walled Carbon Nanotubes/Europium Doped Yttria Oxide Hybrids

In order to improve their optical property, multi-walled carbon nanotubes (MWNTs) were decorated with europium doped yttria oxide (Y2O3:Eu3+) nanoparticles by co-deposition method, and the products were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and luminescence spectroscopy. Experimental results illuminate that MWNTs can be decorated by the Y2O3:Eu3+ nanoparticles at annealed temperature of 600 and 750°C, respectively. The optical property of MWNTs/Y2O3:Eu3+ nanohybrids shows the most excellent when the MWNTs concentratin is 0.5 wt.% and the molar ratios of Eu to Y is 5:95.

Mechanical and electrical properties of multi walled carbon nanotube/ABC block terpolymer composites

Composites of multi-walled carbon nanotubes (MWCNTs) in ABC block terpolymer matrices of different compositions are studied. The composites were obtained by dispersion of MWCNTs in poly(styrene-block-butadiene-block-methyl methacrylate) (SBM) in a selective solvent for the M block, followed by solvent evaporation and compression molding. The structures of the MWCNT/SBM composites are investigated by transmission electron microscopy. The processing conditions, i.e. solvent cast or compression molding, induce different non-equilibrium microstructures and the MWCNTs modify the SBM organization only locally. We show that by fixing the processing procedure we are able to obtain samples with reproducible microstructure and properties. The electrical conductivity thresholds of these composites are lower than 1wt.%. The reinforcing effect of the MWCNTs measured by dynamical mechanical analysis is mainly related to the SBM microstructures of the matrix and to the MWCNT dispersion quality.

146 無加圧焼成法により作製したカーボンナノチューブ/アルミナ複合材料の機械的特性評価に関する研究(材料力学II,一般講演)

146 無加圧焼成法により作製したカーボンナノチューブ/アルミナ複合材料の機械的特性評価に関する研究(材料力学II,一般講演)

多層カーボンナノチューブを用いた天然ゴムコンポジットに関する電気的特性に及ぼすチューブの直径とその分散状態の影響について

多層カーボンナノチューブを用いた天然ゴムコンポジットに関する電気的特性に及ぼすチューブの直径とその分散状態の影響について

Improvement in properties of multiwalled carbon nanotube/polypropylene nanocomposites through homogeneous dispersion with the aid of surfactants

AbstractThe effects of different surfactants on the properties of multiwalled carbon nanotubes/polypropylene (MWCNT/PP) nanocomposites prepared by a melt mixing method have been investigated. Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) were used as a means of noncovalent functionalization of MWCNTs to help them to be dispersed uniformly into the PP matrix. The effects of these surfactant‐treated MWCNTs on morphological, rheological, thermal, crystalline, mechanical, and electrical properties of MWCNT/PP composites were studied using field emission scanning electron microscopy, optical microscopy, rheometry, tensile, and electrical conductivity tests. It was found that the surfactant‐treatment and micromixing resulted in a great improvement in the state of dispersion of MWCNTs in the polymer matrix, leading to a significant enhancement of Young's modulus and tensile strength of the composites. For example, with the addition of only 2 wt % of SDS‐treated and NaDDBS‐treated MWCNTs, the Young's modulus of PP increased by 61.1 and 86.1%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

An electrochemical study of the synthesis and properties of multi-walled carbon nanotube/poly ortho aminophenol composites

Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good uniformity for use as electrodes in electrochemical capacitors were prepared by electropolymerization by using the ionic surfactant as electrolyte, for dispersing CNTs within conducting polymer/carbon nanotube composite films. The capacitance properties were investigated with cyclic voltammetry (CV), discharge tests and ac impedance spectroscopy. The composite electrode shows much higher specific capacitance, better power characteristics and is more promising for application in the capacitor than a pure POAP electrode. The effect and role of MWCNT in the composite electrode are discussed in detail. In comparison with a Ni–POAP/glassy carbon (GC), a Ni–MWCNT–POAP/GC electrode shows a better catalytic performance for the electrocatalytic oxidation of methanol.