, the multi-wallcarbonnanotube (MWNT) and the single-wall carbon nanotube (SWNT). A SWNT is a graphene sheet rolled into a cylinder with typical diameter on the order of 1.4 nm. However, a MWNT consists of several concentric cylinders with diameters
Authors:C. Chang, Y. Chou, J. Tseng, M. Liu, and C. Shu
Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics
regarding stability would represent potential hazards during the production or utilization stage and could be determined by
calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate
the thermokinetic parameters for MWNTs at various compositions.
Thermoanalytical curves showed that the average heat of decomposition (ΔHd) of the MWNTs samples in a manufacturing process was about 31,723 J g−1, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence
of sulfuric acid (H2SO4). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch
addition with reactants of H2SO4. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation
Authors:B. Marosfői, A. Szabó, Gy. Marosi, D. Tabuani, G. Camino, and S. Pagliari
(TG) and varied temperature Raman spectroscopic measurements of melt-blended
polypropylene composites (PP) with double wall (DWNT) and multi-wall carbon
nanotubes (MWNT) revealed that the incorporation of carbon nanotubes into
polymer matrix increased the thermal stability comparing to the virgin polypropylene.
The characterization of reference nanotubes was also done by Raman microscopy
and TG measurements. Varied temperature rheological analysis provided further
information about the thermal decomposition of the composites indicating the
formation of high strength char in case of MWNT and limited applicability
of DWNT at high temperature. The residue of the decomposition of PP-MWNT nanocomposites
consists of nanotubes of spectroscopically higher purity comparing to the
original one indicating the thermally induced chemical changes in the solid
Authors:J. Zeng, Z. Cao, D. Yang, F. Xu, L. Sun, X. Zhang, and L. Zhang
The effects of multi-walled carbon nanotubes (MWNTs) on the phase change enthalpy (ΔH) and the thermal conductivity (κ) of a solid-liquid phase change materials (PCM), palmitic acid (PA), have been investigated.
The results showed that both the ΔH and the κ of the composite were lower than that of PA when the loading of MWNTs was small. As the concentration of MWNTs
in the composites increased, the ΔH of the composites was slightly improved and then decreased linearly. However, the κ of the composites was monotonously increased
from the minimum value. When the loading of MWNTs increased to 5% and no surfactant was added, the κ of the composite was
enhanced to be 26% higher than that of PA. The κ of the composite could be enhanced by CTAB instead of SDBS when the loading
of MWNTs was small, as SDBS showed no obvious effect on the κ of the composites. Furthermore, the effects of surface modification
of MWNTs on the ΔH and the κ of the composites have also been investigated.
Authors:Rossana Iervolino, Elvira Somma, Maria Nobile, Xuming Chen, and Benjamin Hsiao
The flow-induced crystallization behavior of nanocomposites, containing isotactic poly(1-butene) (PB) and functionalized multi-walled
carbon nanotubes (MWNT), was investigated. Three different MWNT concentrations (0.1, 1, 5 wt%) were used to prepare the nanocomposites.
Effects of MWNT and shear flow on the crystallization parameters were evaluated separately. Rheological measurements based
on oscillatory shear revealed induction time and crystallization half-time at the quiescent state, where both parameters exhibited
the nucleating effect of MWNT on PB. Rheological measurements based on steady-state shear flow and short-time shear flow revealed
the evolution of molecular orientation, which was studied in both PB and its nanocomposites. A small increase in crystallization
kinetic was recorded in PB under shear having moderate values of the Weissenberg (We) number. On the other hand, a dramatic synergistic effect of MWNT and shear was detected under the same shear conditions
for nanocomposites. The optical microscopic images exhibited a clear transition from isotropic to row-like morphology in the
case of nanocomposites under shear.
Authors:Eudes Lorençon, Rodrigo G. Lacerda, Luiz O. Ladeira, Rodrigo R. Resende, André S. Ferlauto, Ulf Schuchardt, and Rochel M. Lago
charge transfer from naphthalene anion to CNTs followed by metal reduction [ 14 ]. In this report, this method was used to produce different carbon forms, i.e., SWNTs, multi-walledcarbonnanotubes (MWNTs), and soot, decorated with Au nanoparticles with a
, nanoparticles with high thermal conductivity have shown tremendous potential in heat transfer application [ 10 ]. Zeng et al. enhanced the thermal conductivity of PCMs by adding Ag nanoparticles [ 11 ], Ag nanowires [ 12 ] and multi-walledcarbonnanotubes