Polymer-CNT Nanocomposites

In recent several years, super-capacitors are attracting more and more attention because of their high capacitance and potential applications in electronic devices. The performance of super-capacitors with MWCNTs deposited with conducting polymers as active materials is greatly enhanced compared to electric double-layer super-capacitors with CNTs due to the Faraday effect of the conducting polymer as shown in Fig. 9.18 (Valter et al., 2002). Besides those mentioned above, polymer/ CNT nanocomposites own many potential applications (Breuer and Sundararaj, 2004) in electrochemical actuation, wave absorption, electronic packaging, selfregulating heater, and PTC resistors, etc. The conductivity results for polymer/CNT composites are summarized in Table 9.1 (Biercuk et al., 2002). 

STEM in SEM image obtained on polymer/CNT nanocomposites, experiments are in progress to characterize such sample in 3D with good resolution, contrast and important thickness of transparency, to better characterize entanglements, filler/filler interaction, etc. 

As mentioned earlier, polymerization techniques can also be used in the presence of nanotubes for preparation of polymer/CNT nanocomposite materials. In these, in-situ radical polymerization techniques of polymerization in the presence of CNT filler under or without applied ultrasound. Both new factors (presence of CNT and ultrasound) can affect reaction kinetics, stability of suspension or the size of prepared particles. For example, ultrasound waves can open C=C bond of monomer, which starts polymerization initiation. Thus vinyl monomers (styrene, methyl methacrylate or vinyl acetate) can be polymerized without addition of initiator, only by application of ultrasound. This is called sonochemical polymerization method (15,33,34). 

The suspension polymerization method has become very popular because of its simplicity and the wide variety of monomers which can be effectively polymerized. Prepared spherical particles are applied in different areas of science and technology. It is also the case of polymer/CNT nanocomposite microspheres produced by the modified... 

Electrorheology of Polymer/CNT Nanocomposites Prepared by in-situ Suspension Polymerization... 

From a technological point of view, the dynamic crystallization of composites is of a great interest, because most of processing routes take place under these conditions. Generally, the crystallization and melting behaviour of polymer/CNT nanocomposites is analyzed by differential scanning calorimetry (DSC) analysis the transition temperatures are taken as the peak maximum or minimum in the... 

The polymer/CNT nanocomposites can be used for some other applications, for which conductivity requirements are not as severe. Among these applications may be mentioned electromagnetic interference shielding, electrostatic dissipation, touch panels, display panels, which need to be transparent in addition to presence certain conductivity. The nanocomposites may be also used to dissipate heat or as flame retardant, and in the biological field, as part of sensors (Grady 2011). 

However, there are some important factors in the production of polymer/CNT nanocomposites that must be considered to obtaining success in the development of these nanocomposites. The factors include the interfacial adhesion between the polymer and the CNT, which is essential to permit a good transfer of tension between matrix and filler and the method to produce the nanocomposites, since it is important to obtain an efficient distribution and dispersion of CNT inside the matrix. 

The improvement of mechanical, thermal, electrical, and other properties in polymer/CNT nanocomposites occurs when the CNT are well-dispersed and adhered in the polymeric matrix, which are the major challenges in the production of polymer/CNT nanocomposites. 

The possible methods to produce polymer/CNT nanocomposites and the functionalization ways to modify the surface of CNT and, consequently, to improve their dispersion and adhesion in the polymer matrix will be addressed in the next section. 

Despite the functionalization be a useful tool in the production of polymer/CNT nanocomposites, the control of the functionalization reactions of the hydrophobic and chemically inert surface of the carbon nanotubes remains a major challenge for their use (Likodimos et al. 2014). 

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