scholarly journals Highly Deformable Porous Electromagnetic Wave Absorber Based on Ethylene–Propylene–Diene Monomer/Multiwall Carbon Nanotube Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 858 ◽  
Author(s):  
Hasti Bizhani ◽  
Ali Asghar Katbab ◽  
Emil Lopez-Hernandez ◽  
Jose Miguel Miranda ◽  
Raquel Verdejo
Keyword(s):  
Electromagnetic Interference ◽  
Multiwall Carbon Nanotubes ◽  
Multiwall Carbon Nanotube ◽  
Ethylene Propylene Diene Monomer ◽  
Ethylene Propylene ◽  
Electrical Percolation ◽  
Vulcanized Rubber ◽  
Electrical Percolation Threshold ◽  
High Flexibility ◽  
Multiwall Carbon

The need for electromagnetic interference (EMI) shields has risen over the years as the result of our digitally and highly connected lifestyle. This work reports on the development of one such shield based on vulcanized rubber foams. Nanocomposites of ethylene–propylene–diene monomer (EPDM) rubber and multiwall carbon nanotubes (MWCNTs) were prepared via hot compression molding using a chemical blowing agent as foaming agent. MWCNTs accelerated the cure and led to high shear-thinning behavior, indicative of the formation of a 3D interconnected physical network. Foamed nanocomposites exhibited lower electrical percolation threshold than their solid counterparts. Above percolation, foamed nanocomposites displayed EMI absorption values of 28–45 dB in the frequency range of the X-band. The total EMI shielding efficiency of the foams was insignificantly affected by repeated bending with high recovery behavior. Our results highlight the potential of cross-linked EPDM/MWCNT foams as a lightweight EM wave absorber with high flexibility and deformability.

Plain para-aramid/phenolic multiwall carbon nanotubes prepreg/multistiched preform composites: Experimental characterization of mode-I toughness

2018 ◽  
Vol 53 (13) ◽  
pp. 1847-1864 ◽  
Author(s):  
K Bilisik ◽  
E Sapanci
Keyword(s):  
Fracture Toughness ◽  
Multiwall Carbon Nanotubes ◽  
Beam Theory ◽  
Mode I ◽  
Multiwall Carbon Nanotube ◽  
Axial Filament ◽  
Pull Out ◽  
Fiber Bridging ◽  
Nanotube Composites ◽  
Multiwall Carbon

The fracture toughness (mode-I) properties of nanostitched para-aramid/phenolic multiwall carbon nanotube prepreg composites were investigated. The fracture toughness (GIC) of the stitching and nanostitched composites showed 42-fold and 41-fold (beam theory), 18-fold and 21-fold (modified beam theory) increase compared to the control, respectively. The prepreg para-aramid stitching yarn and nanostitched yarn were dominant parameters. The toughness resistance to arrest crack growth in the nanostitched composite was primarily due to nanostitching fiber bridging and pull-out, and was secondarily due to nanotubes and biaxial fiber bridging and pull-out. The failed surfaces of the nanostitched and stitching composites had tensile filament failures in the aramid stitching fibers where filament/matrix/nanotube debonding and axial filament fibrillar splitting were found. The results indicated that stitching yarn and the nanotubes arrested the crack propagation. Therefore, the nanostitched and stitched para-aramid/phenolic composites displayed a better damage resistance performance compared to those of the control or nanotube composites.

Electroless Coating of Silver on Multiwall Carbon Nanotubes

2012 ◽  
Vol 710 ◽  
pp. 774-779
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Carbon Nanotubes ◽  
Surface Modification ◽  
Multiwall Carbon Nanotubes ◽  
Activation Process ◽  
Multiwall Carbon Nanotube ◽  
Effective Utilization ◽  
Electroless Coating ◽  
Silver Matrix ◽  
Electrical Brush ◽  
Multiwall Carbon

Silver reinforced with carbon nanotubes, instead of graphite, would increase both the electrical conductivity, hardness and wear resistance of the electrical brush materials. The effective utilization of carbon nanotubes in the Ag/CNT composite depends strongly on its uniform distribution and strong interfacial adhesion to the silver matrix and thus demands for its surface modification. In order to carry out the surface modification of carbon nanotubes, electroless coating was given to them after liquid phase oxidation, sensitization and activation process. The room-temperature chemical treatment results in a nominally complete coating over the entire outer surface of multiwall carbon nanotube. The surface morphology of the carbon nanotubes after each step has been studied using TGA, DSC, XRD, FTIR and SEM.

scholarly journals Multiwall Carbon Nanotube-Induced Apoptosis and Antioxidant Gene Expression in the Gills, Liver, and Intestine ofOryzias latipes

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jin Wuk Lee ◽  
Young Chul Choi ◽  
Rosa Kim ◽  
Sung Kyu Lee
Keyword(s):  
Gene Expression ◽  
Multiwall Carbon Nanotubes ◽  
Gene Induction ◽  
Multiwall Carbon Nanotube ◽  
Antioxidant Gene ◽  
Significant Gene ◽  
Antioxidant Gene Expression ◽  
And Gender ◽  
Induced Apoptosis ◽  
Multiwall Carbon

Multiwall carbon nanotubes (MWCNTs) have many attractive properties with potential applications in various fields. Despite their usefulness, however, the associated waste can be hazardous to the environment. To examine adverse effects in aquatic environments,Oryzias latipeswere exposed to MWCNTs dispersed in water for 14 days and apoptosis and antioxidant gene expression were observed. This work showed that in gills exposed to 100 mg/L MWCNTs for 4 days, there was significantp53,caspase-3 (Cas3),caspase-8 (Cas8), andcaspase-9 (Cas9)gene expression relative to the controls, whilecatalase (CAT)andglutathione-S-transferase (GST)expression were reduced. At 14 days,CAT,GST, andmetallothionein (MT)were induced significantly in the gills andCas3,Cas8, andCas9were induced in the liver. No significant gene induction was seen in intestine. Intracellular reactive oxygen species (ROS) were increased significantly only at 14 days. Histologically, no apoptosis was observed with exposure to 100 mg/L MWCNTs for 21 days. The gills were more sensitive to MWCNT toxicity than the other organs. Males had higher apoptosis gene induction than females. These results demonstrated that MWCNTs could cause apoptosis in a manner influenced by tissue and gender in aqueous environments.

Optimization of Chemical Vapor Deposition Synthesis Conditions for Multiwall Carbon Nanotube by Statistical Analysis of Experiment

2008 ◽  
Vol 55-57 ◽  
pp. 533-536
Author(s):  
P. Saiprasert ◽  
D. Koolpiruck ◽  
S. Chiangga
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Multiwall Carbon Nanotubes ◽  
Statistical Design ◽  
Chemical Vapor ◽  
Multiwall Carbon Nanotube ◽  
Synthesis Conditions ◽  
Fourier Transform Raman ◽  
Multiwall Carbon

The optimization of chemical vapor deposition synthesis conditions for multiwall carbon nanotubes (MWCNTs) was experimentally investigated. Carbon nanotubes were grown on cobalt substrate thicknesses of 20, 100 and 1000 nm at 700 and 900 0C with 2 replications. The configuration and morphology of the carbon nanotubes were investigated by scanning electron microscope and Fourier transform raman spectrometer, respectively. The tendency of the parameters was evaluated by statistical design of experiment. Observations on samples produced under our optimised production process, showed that a large number of MWCNTs bundles were produced. Diameter of MWCNTs bundles ranges between 30 and 100 nm throughout the samples. From the variance analysis of the Raman spectra we observe that the thickness of cobalt and temperature of synthesis are highly significant in which the coherence length and innermost diameter increase for either the thickness increases or the temperature decreases.

A strategy to achieve enhanced electromagnetic interference shielding at ultra-low concentration of multiwall carbon nanotubes in PαMSAN/PMMA blends in the presence of a random copolymer PS-r-PMMA

RSC Advances ◽  
2016 ◽  
Vol 6 (32) ◽  
pp. 26959-26966 ◽  
Author(s):  
Suryasarathi Bose ◽  
Maya Sharma ◽  
Avanish Bharati ◽  
Paula Moldenaers ◽  
Ruth Cardinaels
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Interference ◽  
Multiwall Carbon Nanotubes ◽  
Random Copolymer ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Pmma Blends ◽  
Multiwall Carbon

Mediated by the PS-r-PMMA, the MWNTs were mostly localized at the interface and bridged the PMMA droplets. This strategy led to enhance EMI shielding effectiveness at 0.25 wt% MWNTs through multiple scattering from MWNT covered droplets.

Role of Multiwall Carbon Nanotubes (MWCNT) on Electrical Conductivity of Polymer Composite as Alternative Materials for Bipolar Plate Fuel Cell

2013 ◽  
Vol 737 ◽  
pp. 183-190 ◽  
Author(s):  
Anne Zulfia ◽  
Sutopo ◽  
Bangkit Indriyana ◽  
M.E. Albar ◽  
S. Rohman
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Multiwall Carbon Nanotubes ◽  
Material Design ◽  
Bipolar Plate ◽  
Multiwall Carbon Nanotube ◽  
Crucial Component ◽  
Carbon Nano Tube ◽  
Multiwall Carbon

Polypropylene can be improved an electrical conductivity by addition of carbon and multiwall carbon nanotube (MWCNT) as well as combination with copper (Cu) powder. Multiwall carbon nanotube used from 0.1 wt%, 0.5 wt% to 1 wt% while the addition of Cu powder into PP/C was various from 0.1 wt%, 0.2wt% to 0.5wt% respectively. This research focuses on material design of composite based on polymer and carbon to improve an electrical conductivity according to electrical conductivity requirement for bipolar plate. Bipolar plate is one of the components in PEMFC constituted a crucial component that collects and transfers electron from the anode to the cathode, therefore it should possess high electrical conductivity. The main discussion in this research is to analyze the role of multiwall carbon nano tube (MWCNT) and copper on electrical conductivity of polymer composites produced. Functional groups analysis using Fourier Transform Infrared Spectroscopy (FTIR) was also carried out to investigate whether carbon has been mixed perfectly within polypropylene. It is found that the effect of adding a small amount of MWCNT and Cu have improved their electrical conductivity of composites up to 15.62 S/cm.

scholarly journals Gold Plate Electrodes Functionalized by Multiwall Carbon Nanotube Film for Potentiometric Thallium(I) Detection

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1160
Author(s):  
Saad S. M. Hassan ◽  
Sabah. M. Abdelbasir ◽  
M. Abdelwahab Fathy ◽  
Abd El-Galil E. Amr ◽  
Mohamed A. Al-Omar ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Multiwall Carbon Nanotubes ◽  
Ternary Mixtures ◽  
Indicator Electrode ◽  
Multiwall Carbon Nanotube ◽  
Plate Electrode ◽  
Membrane Technique ◽  
Gold Plate ◽  
Sensing Membrane ◽  
Multiwall Carbon

Solid-contact potentiometric ion-selective electrodes (SC-ISEs) for thallium determination have been designed using multiwall carbon nanotubes (MWCNTs) as the ion-to-electron transducer. Dispersed MWCNTs were drop-casted over a gold plate electrode. Two different crown ethers were used in the sensing membrane for the recognition of thallium (I). Sensorsbased on dibenzo-18-crown-6 (DB18C6) as a neutral carrier and NaTPB as an anionic additive exhibited a near Nernstian response of 57.3 mV/decade towards Tl+ ions over the activity range 4.5 × 10−6–7.0 × 10−4 M, with a limit of detection of 3.2 × 10−7 M. The time required to achieve 95% of the steadyequilibrium potential was <10 s. The complex formation constant (log βML) between dibenzo-18-crown-6 and thallium (I) (i.e., 5.99) was measured using the sandwich membrane technique. The potential response was pH independent over the range 3.0–9.5. The introduction of MWCNTs as an electron-ion-transducer layer between gold plate and the sensing membrane lead to a smaller membrane resistance and a large double layer capacitance, which was proven using impedance spectra and chronopotentiometry (i.e., 114.9 ± 12 kΩ, 52.1 ± 3.3 pF, 200 ± 13.2 kΩ, and 50 ± 4.2 µF). Additionally, reduction ofthe water layer between the sensing membrane and the underlying conductor wastested. Thus, it is clear that MWCNTs can be used as a transducing layer in SC-ISEs. The proposed sensor was introduced as an indicator electrode for potentiometric titration of single and ternary mixtures of I−, Br−, and S2− anions.

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