Nanocomposites carbon nanotubes dispersion

Ding et al. prepared functionalized graphene/carbon nanotube/PPy ternary nanocomposites by one-step electrochemical polymerization [143]. The functionalized graphene and carbon nanotube disperses homogeneously in the PANI matrix and the ternary nanocomposite is highly... 

Barroso-Bujans et al. [60] prepared nanocomposites of carbon nanotubes and sul-fonated ethylene-propylene-norbomene terpolymer and compared the mechanical properties of carbon nanotubes and carbon black ethylene-propylene-norborene composites. They also evaluated the effect of carbon nanotube dispersion on the mechanical, thermal, and electrical behavior. 

Zeng et al. (2010) studied the effects of carbon nanotube dispersion and PMMA foam cell morphology. They observed that in nanocomposites where CNTs were not well dispersed, the foam exhibited bimodal cell size distribution (Figure 1.12). A smaller amount of big bubbles are distributed in a large number of significantly smaller bubbles. By analysis based on nucleation theory and deliberate experiments, they elucidated that such bimodal cell size distribution resulted from mixed mode... 

Ukai, T. Sekino, A. Hirvonen, N. Tanaka, T. Kusunose, T. Nakayama, and K. Niihara, Preparation and electrical properties of carbon nanotubes dispersed zirconia nanocomposites. Key Eng. Mat. 2006 317-318 661-664. 

The UV-visible absorption of nanocomposites of poly(L-lysine) and single walled carbon nanotubes was studied by Kim et al. [22]. The carbon nanotubes in water showed an absorption peak at 254 nm, which is typical for this kind of material. For the carbon nanotubes dispersed in the polymer the absorbance occurred at 207 and 266 nm, while the pure poly(L-lysine) showed an absorbance maximum at 219 nm. The peaks of nanocomposite were shifted to shorter wavelengths due to the wrapping of the polymer. The authors suggested that this support the existence of significant van der Waals interactions between the polymer and the nanotubes. 

CNTs can enhance the thermal properties of CNT-polymer nanocomposites. The reinforcing function is closely associated with the amount and alignment of CNTs in the composites. Well-dispersed and long-term stable carbon nanotubes/ polymer composites own higher modulus and better thermal property as well as better electronic conductivity (Valter et al., 2002 Biercuk et al., 2002). Both SWNT and MWNT can improve the thermal stability and thermal conductivity of polymer, the polymer-CNT composites can be used for fabricating resistant-heat materials. 

These examples of functionalization of carbon nanotubes demonstrate that the chemistry of this new class of molecules represents a promising field within nanochemistry. Functionalization provides for the potential for the manipulation of their unique properties, which can be tuned and coupled with those of other classes of materials. The surface chemistry of SWCNTs allows for dispersibility, purification, solubilization, biocompatibility and separation of these nanostructures. Additionally, derivatization allows for site-selective nanochemistry applications such as self-assembly, shows potential as catalytic supports, biological transport vesicles, demonstrates novel charge-transfer properties and allows the construction of functional nanoarchitectures, nanocomposites and nanocircuits. 

As another example, Kashiwagi et al.7 have investigated the flammability of polymer/single wall carbon nanotube (SWNT) nanocomposites. It has been observed that in the case where the nanotubes were relatively well-dispersed, a nanotube containing network structured layer was formed without any major cracks or openings during the burning tests and covered the entire... 

Kashiwagi, T., Du, F., Winey, K.I., Groth, K.M., Shields, J.R., Bellayer, S., Kim, S., and Douglas, J.F. 2005. Flammability properties of polymer nanocomposites with single-walled carbon nanotubes Effects of nanotube dispersion and concentration. Polymer 46(2) 471 181. 

Grossiord, N., Loos, J., Regev, O., and Koning, C. E. Toolbox for dispersing carbon nanotubes into polymers to get conductive nanocomposites, Chem. Mater. (2006), 18, 1089-1099. 

At the steps before the elaboration of carbon nanotube nanocom-posites, wet-STEM can be used for the characterization of nanotubes dispersed in a liquid (see Figure 3.18), and for polymer latex/ nanotubes mixing (before evaporation or freeze-drying to elaborate polymer/carbon nanotube nanocomposites). 

We review the research on preparation, morphology, especially physical properties and applications of polyurethane (PU)/carbon nanotube (CNT) nanocomposites. First, we provide a brief introduction about the preparation of PU/CNT nanocomposites. Then, the functionalization and the dispersion morphology of CNTs as well as the structures of the nanocomposites are also introduced. After that, we discuss in detail the effects of carbon nanotubes on the physical properties (including mechanical, thermal, electrical, rheological and other properties) of PU/CNT nanocomposites. The potential applications of these nanocomposites are also addressed. Finally, the challenges and the research that needs to be done in the future for achieving high-performance polyurethane/carbon nanotube nanocomposites are prospected. 

Besides covalent functionalization of carbon nanotubes, non-covalent interaction between CNTs and polyurethane can also help fabricate uniform CNT dispersion nanocomposites. A dominant improvement in the dispersion of MWNTs in hyperbranched polyurethane (HBPU) matrix was found, and good solubility of... 

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