Carbon nanotube storage modulus

FIGURE 4.6 Variation of storage modulus against temperature for ethylene-vinyl acetate (EVA) nanocomposites having different loadings of carbon nanotube (CNT) and ANT. (From George, J.J., Sengupta, R., and Bhowmick, A.K., J. Nanosci. Nanotechnol., 8, 1, 2007. Courtesy of American Scientific Publishers.)... 

FIGURE 28.22 Storage modulus G vs temperature of carbon nanotube (CNT)/mbber composite. (From Lopez-Manchado, M.A. et al., J. Appl. Polym. Sci., 92, 3394, 2004.)... 

As already reported by several authors, the addition of carbon nanotubes did not affect the storage modulus in the glassy region, nevertheless a strong increase with the filler content is observed in the rubbery region. In conventional composites, this increase is mainly attributed to interfacial interactions leading to introduction of additional cross-links into the network by the filler. These interfacial interactions contribute to the formation of an adsorption layer whose thickness has been estimated around 2 or 3 nm and where... 

Carbon nanotubes ast-asa reagent and an increased crystallization Superposed of flow conditions, enhanced dynamic viscosity, and storage modulus Tendency of the polymer chains to undergo intermolecule slippage is received and melt viscosity enhanced by use of coupling agents... 

Fama LM, Pettarin V, Goyanes S, Bernal CR (2011) Starch based nanocomposites with improved mechanical properties. Carbohydr Polym 83 1226-1231 Fama LM, Ganan P, Bernal CR, Goyanes S (2012) Biodegradable starch nanocomposites with low water vapor permeability and high storage modulus. Carbohydr Polym 87 1989-1993 Fama L, Kumar R (2014) Nanocomposites based on polylactic acid (PLA) reinforced by functionalized carbon nanotubes (CNT). In Kumar R (ed) Polymer-matrix composites t3fpes, applications and performance. Nova Science Publishers, Inc. USA (in press)... 

There are various types of carbon nanofillers which include carbon black, multi walled carbon nanotubes (MWCNTs), and single walled carbon nanotubes (SWCNTs) [27]. In this section the effect of these nano fillers on viscoelastic behavior is thoroughly discussed. The physicomechanical properties of conductive carbon black (CCB) filled ethylene acrylic elastomer (AEM) vulcanizates have been reported by B.P. Sahoo et al. They have discussed thoroughly about the effect carbon black concentration on the viscoelastic behavior of CCB-AEM nanocomposites with respect to temperature variation. Figure 10a, b represents the variation of storage modulus and loss modulus with temperature. It is observed that the value of storage modulus (E ) increased with increase in filler loading in the... 

Yan et al. (2011) prepared rigid PU nanocomposite foams reinforced with variable concentrations of carbon nanotubes for long-term use electrical conductive components. Particularly, for a 2 wt% CNT content, rigid PU foams presented around a 30% increase in compression properties and a 50% increase in storage modulus, both measured at room temperature, when compared to the unfilled PU foam, thus demonstrating the effective mechanical reinforcement effect that low amounts of carbon nanotubes have on PU foams. 

The impact of aspect ratio and alignment of the carbon nanotubes on the nanocomposite conductivity has been studied recently (both experimentally and computationally) by Winey and coworkers [165-167]. In particular, Du et td. [165] demonstrated that in a poly(methyl methacrylate) (PMMA)/single wall carbon nanotube (SWCNT) nanocomposite, conductivity increases as a function of the SWCNT loading as predicted by Eq. (7.10), with a power-law exponent of 2.3 and percolation threshold of 0.39 wt%. Interestingly, the rapid increase in conductivity was accompanied by a rapid increase in the storage modulus, G (Figure 7.17). In fact,... 

Multiwall carbon nanotube (MWCNT) reinforced thermotropic liquid crystalline polymer (TLCP) nanocomposites were prepared by a melt compounding process. Incorporation of small quantity of the MWCNT improved the thermal stability of MWCNT reinforced TLCP nanocomposites. The rheological behavior of TLCP/MWCNT nanocon sites was dq)endent on the MWCNT content. The complex viscosity and storage modulus of TLCP/MWCNT nanocomposites increased with increasing MWCNT, resulting fiom physical interactions such as the nanotube-polymer noatrix interactions and the nanotube-nanotube interactions. This increment effect was more significant at lower frequencies. 

As an example of the behavior of such nanocomposites. Figure 30a shows storage modulus G measured for blends of single-wall carbon nanombe (SWNT) in a matrix of poly(methyl methacrylate) (PMMA M = 1.0 x 10 ). ° The nanotubes are uniformly dispersed in the range of the nanotube content Wf examined, but the blends exhibit elastic (solid-like) response, cu-insensitive G plateau at low cu, as Wf is inaeased beyond a threshold value Wf c (=0.12wt.% determined from percolation analysis ). This plateau is attributable to the motional constraint on the polymer chains due to a nanotube network formed through these chains. The elasticity of the... 

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