Environmental Engineering Reference
In-Depth Information
1.0
0.8
0.6
0.4
0.2
0.
0.00
0.35
0.70
MWCNT / wt%
1.05
1.40
1.75
Figure. 13.5
Oxygen permeability of PMMA/f-MWCNT nanocomposites at constant
pressure of (0.5 psi) [22].
studied [22], as shown in Figure 13.5. h e oxygen permeability of PMMA/
f-MWCNT nanocomposites with 1.75 wt% of MWCNTs loading is about
eight times less than that of virgin PMMA. h e reduction of permeability
arises from the longer dif usive path of the penetration of the oxygen in the
presence of MWCNTs. h e incorporation of MWCNT in PMMA matrix is
particularly excellent at maximizing the path length due to the high aspect
ratio. Furthermore, the presence of MWCNT introduces a torturous path
for which the oxygen travels longer dif usive path. Hence oxygen perme-
ability of PMMA/MWCNT nanocomposites is less than that of PMMA
matrix. h e tremendous decrease in oxygen permeability with increasing
MWCNT (wt%) is due to good dispersion of MWCNTs in polymer matrix
of PMMA/f-MWCNT composites.
13.4.4.3 Other Nanomaterials
Silica nanoparticles (nSiO
2
) have been reported to improve tensile proper-
ties of polypropylene, starch, starch/polyvinyl alcohol, besides decreasing
water absorption by starch and improving oxygen barrier of polypropylene
prepared nanocomposites of polyvinyl alcohol with nSiO
2
by radical copo-
lymerization of vinyl silica nanoparticles and vinyl acetate. h e nanocom-
posites had improved thermal and mechanical properties when compared
to the pure polyvinyl alcohol, due to strong interactions between nSiO
2
and the polymer matrix via covalent bonding.
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