MWCNT/iPP-g-MA nanocomposite

SWCNT/ and MWCNT/iPP-g-MA nanocomposites were prepared by latex technology and a thermal and morphological evaluation of their properties was subsequently carried out. ... 

Figure 5.5 Storage modulus G plotted as a function of the loss modulus G" as determined from frequency sweep experiments for MWCNT/iPP-g-MA nanocomposites at 170°C, the temperature at which the nanocomposites were compression molded for 2 min. The diagonal line corresponds to G = G". (Reproduced with permission from ref. 28. Cop3n ight 2010 Elsevier Ltd]...

Figure 5.3 Conductivity (four-point measurements) as a function of MWCNT concentration for MWCNT/iPP-g-MA and MWCNT/PS nanocomposites.

Figure 5.3 [resp. Figure 5.4]. Upon further CNT addition, the conductivity levels off around 70 S/m (resp. 7 S/m] at 2 wt% of MWCNTs (resp. SWCNTs], irrespective of the type of matrix. Note, however, that the same CNTs dispersed in a PS matrix, following the same experimental procedure, exhibit significantly higher percolation threshold values than in the CNT/iPP-g-MA series, namely, of the order of 0.55 wt% for SWCNT/PS systems and 0.81 wt% for MWCNT/PS nanocomposites.

As an additional factor, the lower melt viscosity at the compression molding temperature of the iPP-g-MA matrix in comparison with the PS system (about 50 Pa s at 170°C for the former in non-emulsified form vs. well-above 10 Pa s at 180°C for the latter) certainly favors the lowering of the experimental percolation threshold, both for SWCNT and MWCNT nanocomposites (see Table 5.1). A lower melt viscosity of the matrix, indeed, reduces the average CNT-CNT distance and was... 

As shown in Table 5.1, the percolation thresholds in both SWCNT-and MWCNT-based nanocomposites of iPP-g-MA and PS roughly... 

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