MWCNT loading

Figure 5.5. Mechanical properties of PE and MWCNT-PE nanocomposites as a function of MWCNT loading, McNally et al. (53).

Yuenetal. 2007 (70) MWCNT Nanotech Port Company, Shenzhen, China Silane-modified MWCNT (Si-MWCNT) Solution mixing CNT Loading levels 0.5 to 3.85 wt% Used a copolymer PMMA-VTES as cross-linkable PMMA to 1 Si-MWCNT 1 Surface and volume electrical resistivity decreased with increasing content of Si-MWCNT Thermal conductivity increased by 87% at 0.99wt% Si-MWCNT loading Thermal stability increased substantially by adding Si-MWCNT due to the presence of Si-O-Si groups SEM and TEM revealed that Si-MWCNT was completely dispersed in the polymer matrix... 

Similar to Wu and Liao (75), Wu et al. (74) used a DMA (Model -242C, NETZSCH Co.) and a rheometer (HAAKE RS600, Thermo Electron Co.) to evaluate the viscoelastic behavior of the carboxylic-acid-functionalized MWCNTs reinforced PCL/PLA blend. Using DMA, it was observed that, with the increase of MWCNT loading, the Tg of the blend system shifted to higher temperatures. This agrees with the results obtained from the other studies discussed above and indicates the MWCNTs are compatible with the blend. The viscoelastic properties observed via rheometer were similar to those by Wu et al. (73), discussed above. 

Moon et al. (61) showed from the mass loss curves for the degradation of PLLA and PLLA-MWCNT nanocomposites that PLLA degraded without forming any residue, but the nanocomposites left a residue of about 3-10% (Figure 9.14). Additionally, the decomposition temperature (Td), at 10% weight loss, was found to increase with the MWCNT loading by 10-20%. Rapid weight loss also took place at around 300 °C in both PLA and PLA nanocomposites. Similar results were also obtained by (64,73,75,76). 

Figure 9.20 Dependence of (a) and (b) 6 value of PANl-MWCNT-loaded PS composites on the loading of PANl-MWCNT. Reprinted from Ref [11] with permission from Elsevier.

Figure 9.22 (a) Variation of reflection (SEj,) and absorption (SE ) losses with MWCNT loading and magnified SEM image (inset) showing dispersed CNTs and voids, (b) schematic representation of radiation shield interaction and involved MIR phenomenon. Reprinted from Ref [12] with permission from Springer. 

Figure 9.23 Frequency dependence of losses due to reflection (SEj ) and absorption (SE ) for MWCNT-loaded PANl nanocomposites having different loadings of MWCNT relative to aniline monomer viz. PCNTO (0.0 wt.%), PCNT5 (5.0 wt.%), PCNTIO (10 wt.%), PCNT20 (20 wt.%), and PCNT25 (25 wt.%). Loss tangent (tan 6) of in-situ synthesized PANl-MWCNT nanocomposites as a function of MWCNT loading. Reprinted from Ref [4] with permission from Elsevier.

The actual losses can be computed by normalization of these losses with storage terms [i.e., by ratio of dielectric losses/imaginary permittivity is") with dielectric constant/real permittivity ( )] to quantity loss tangent (tan 8). In case of in-situ formed PANI/MWCNT nanocomposites, improvement of dielectric properties leads to high value of loss tangent (Figure 9.23b) which further increases with increase in MWCNT loading. 

Fig. 11 Sepiolite-multiwalled carbon nanotubes (MWCNT) hybrid buckypapers (a) electrical conductivity versus MWCNT loading (b) Field emission SEM image of a buckypaper containing almost 6 1 (w/w) sepiolite/CNT. Reprinted from [259], Copyright (2014), with permission from...

Fig. 23 Storage modulus at 30 °C of the blends in MD and TD at various MWCNT loadings MD machine direction, TD transverse direction [101]...

Fig. 9. Heat capacity of [C4rriim][PF6]-based ionanofluid for two different MWCNTs loadings as a function of temperature (legends - [C4mim][PF6] - [C4mim][PF6] +1 wt% of MWCNTs O - [C4inim][PF6] + 1.5 wt% of MWCNTs). The data are expressed in mass units as the molecular weight of the MWCNTs is not known.

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