scholarly journals Effect of Matrix Viscosity on Rheological and Microwave Properties of Polymer Nanocomposites with Multiwall Carbon Nanotubes

2014 ◽  
Vol 44 (2) ◽  
pp. 83-96 ◽  
Author(s):  
R. Kotsilkova ◽  
E. Ivanov ◽  
D. Bychanok ◽  
A. Paddubskaya ◽  
P. Kuzhir
Keyword(s):  
Carbon Nanotubes ◽  
Percolation Threshold ◽  
Multiwall Carbon Nanotubes ◽  
Electromagnetic Shielding ◽  
Microwave Properties ◽  
Multiwalled Carbon ◽  
Low Viscosity ◽  
The Matrix ◽  
Multiwall Carbon ◽  
Rheological Percolation

Abstract Nanocomposites of multiwalled carbon nanotubes (MWCNTs) in epoxy resin and polypropylene (PP) are studied. The effect of matrix viscosity on the degree of dispersion of nanotubes is determined by rheological methods. Rheology and microwave properties are correlated to estimate the optimal limits of nanofiller content required for improving the performance of nanocomposites. Rheological percolation threshold is determined for both types nanocomposites, ϕp=0.27% for the epoxy/MWCNT and; ϕp=1.5% for the PP/MWCNT, as found critical for achieving a network structure of interacting nanotubes in the matrix polymer. Good electromagnetic shielding efficiency was obtained for nanocomposites at nanotube contents above the rheological percolation. Low viscosity matrix facilitates contacts between MWCNTs, resulting in appearance of electromagnetic shielding at very low percolation threshold.

scholarly journals Application of Response Surface Methodology for Optimization of Urea Grafted Multiwalled Carbon Nanotubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Norazlina Mohamad Yatim ◽  
Azizah Shaaban ◽  
Mohd Fairuz Dimin ◽  
Faridah Yusof ◽  
Jeefferie Abd Razak
Keyword(s):  
Carbon Nanotubes ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Nitrogen Uptake ◽  
Plant Nutrition ◽  
Multiwall Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Reflux Time ◽  
Use Efficiency ◽  
Multiwall Carbon

Efficient use of urea fertilizer (UF) as important nitrogen (N) source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nanocarrier is developed based on functionalized multiwall carbon nanotubes (f-MWCNTs) grafted with UF to produce urea-multiwall carbon nanotubes (UF-MWCNTs) for enhancing the nitrogen uptake (NU) and use efficiency (NUE). The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10–0.60 wt%) and functionalization reflux time (12–24 hrs) with the corresponding responses (NUE, NU) were structured via the Response Surface Methodology (RSM) based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (pvalue < 0.05) for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

scholarly journals CORE-TUBE MORPHOLOGY OF MULTIWALL CARBON NANOTUBES

2010 ◽  
Vol 24 (01n02) ◽  
pp. 288-294 ◽  
Author(s):  
MOTOHIRO SATO ◽  
HIROYUKI SHIMA ◽  
KOHTAROH IIBOSHI
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Medium ◽  
Multiwall Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Core Tube ◽  
Cross Sectional ◽  
The Cross ◽  
Sectional Shape ◽  
Strain Model ◽  
Multiwall Carbon

The present paper investigates the cross-sectional morphology of Multiwalled Carbon Nanotubes (MWNTs) restrained radially and circumferentially by an infinite surrounding elastic medium, subjected to uniform external hydrostatic pressure. In this study, a two-dimensional plane strain model is developed, assuming no variation of load and deformation along the tube axis. We find some characteristic cross-sectional shapes from the elastic buckling analysis. The effect of the surrounded elastic medium on the cross-sectional shape which occurs due to pressure buckling is focused on by the comparison with the shape for no elastic medium case in our discussion. It is suggested that in no embedded elastic medium cases, the cross-sectional shapes of inner tubes maintain circle or oval; on the other hand, an embedded medium may cause inner tube corrugation modes especially when the number of shells for MWNTs is small.

High Electromagnetic Shielding of a 2.5-Gbps Plastic Transceiver Module Using Dispersive Multiwall Carbon Nanotubes

2008 ◽  
Vol 26 (10) ◽  
pp. 1256-1262 ◽  
Author(s):  
Chia-Ming Chang ◽  
Jin-Chen Chiu ◽  
Yi-Fen Lan ◽  
Jhe-Wei Lin ◽  
Chao-Yung Yeh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Electromagnetic Shielding ◽  
Transceiver Module ◽  
Multiwall Carbon

Simultaneous enhancement in mechanical strength, electrical conductivity, and electromagnetic shielding properties in PVDF–ABS blends containing PMMA wrapped multiwall carbon nanotubes

2015 ◽  
Vol 17 (22) ◽  
pp. 14856-14865 ◽  
Author(s):  
Goutam Prasanna Kar ◽  
Sourav Biswas ◽  
Suryasarathi Bose
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Mechanical Strength ◽  
Multiwall Carbon Nanotubes ◽  
Electromagnetic Shielding ◽  
Unique Approach ◽  
Shielding Properties ◽  
Multiwall Carbon

A unique approach was adopted to drive the multiwall carbon nanotubes (MWNTs) to the interface of immiscible PVDF–ABS blends by wrapping the nanotubes with a mutually miscible homopolymer (PMMA).

scholarly journals Incorporation of Functionalized Multiwall Carbon Nanotubes into a Polyurethane Matrix

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Martin Michálek ◽  
Michael Bredol
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Aqueous Suspension ◽  
Sodium Dodecyl ◽  
Multiwall Carbon Nanotubes ◽  
Glass Substrates ◽  
Functionalized Mwcnts ◽  
Multiwall Carbon

Functionalized and raw multiwall carbon nanotubes (MWCNTs) were investigated colloid-chemically in order to study the role of polar versus nonpolar interaction with a polyurethane (PU) matrix. Both kinds of MWCNTs were dispersed by ultrasonication in the presence of a surfactant (sodium dodecyl sulphate) in aqueous solution. Functional groups on the nanotube surface were characterized by infrared spectroscopy and by theζ-potential in aqueous suspension. Such suspensions were added to waterborne PU dispersions, drop-cast on glass substrates and cured. The percolation threshold for electrical conductivity with polar (functionalized) MWCNTs was reached at 0.24 wt.%, whereas at concentrations as high as 2 wt.%, PU films with nonpolar MWCNTs stayed below the percolation threshold. With an addition of 0.4 wt.% polar MWCNTs, the electrical conductivity increased to >10−6 S/cm in the cured coating layer. These results are interpreted with respect to the chemical nature of the PU matrix.

Microwave absorbers designed from PVDF/SAN blends containing multiwall carbon nanotubes anchored cobalt ferrite via a pyrene derivative

2015 ◽  
Vol 3 (23) ◽  
pp. 12413-12426 ◽  
Author(s):  
Sourav Biswas ◽  
Goutam Prasanna Kar ◽  
Suryasarathi Bose
Keyword(s):  
Carbon Nanotubes ◽  
Magnetic Nanoparticles ◽  
Polyvinylidene Fluoride ◽  
Cobalt Ferrite ◽  
Multiwall Carbon Nanotubes ◽  
Electromagnetic Shielding ◽  
Microwave Absorbers ◽  
Multiwall Carbon

Lightweight and flexible electromagnetic shielding materials were designed by selectively localizing multiwall carbon nanotubes (MWNTs) anchored magnetic nanoparticles in melt mixed co-continuous blends of polyvinylidene fluoride (PVDF) and poly(styrene-co-acrylonitrile) (SAN).

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