Environmental Engineering Reference
In-Depth Information
1.2
1.0
0.8
0.6
0.4
0.2
0
2
4
6
8
Clay content, wt %
Figure 13.4
Oxygen permeability values of the soy/clay bionanocomposites as a function
of clay weight percent at a pressure of 5 psi [21].
oxygen l ow rate through all the nanocomposites was observed to be less in
comparison to the virgin PMMA at dif erent pressures up to 5 psi; the l ow
rate was found to decrease with an increase in percentage clay loading. h e
l ow rate of PMMA/clay nanocomposites was reduced by 17% as compared
to virgin PMMA at 3% clay concentration. h is is due to the tortuous path
created as a result of exfoliation of clay during sonication [20].
h e oxygen l ow rate of the soy/clay bionanocomposites was found to
be decreased in proportion to clay loading of 2% (Figure 13.4). At 8% clay
concentration, the oxygen permeability was reduced by 6 times as com-
pared to the virgin protein. h is is because the clay nanoparticles act as
physical obstacle, retarding the movement of the gas [21].
13.4.4.2 Carbon Nanotube as Fillers
Carbon nanotubes may consist of a one-atom thick single-wall nanotube,
or a number of concentric tubes called multiwalled nanotubes, having
extraordinarily high aspect ratios and elastic modulus. Several polymers
have been found to have their tensile strength/modulus improved by addi-
tion of carbon nanotubes, such as polyethylene naphtalate, polyvinyl alco-
hol, polypropylene and a polyamide. h e polylactic acid not only had its
tensile properties improved by carbon nanotubes, but also had its water
vapor transmission rate decreased by 200%.
h e oxygen permeability of virgin PMMA and PMMA/functionalized
multiwalled carbon nanotube (f-MWCNT) nanocomposites has been
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