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3. 5. Foam behaviors and cell geometry
Figure 7 presents optical micrographs of the cross-sectional surfaces
of the PBS nanocomposite foams with 2 wt% MWNTs content
produced via the SOAM method and foamed for 5 min as a function of
temperature and CBA content. All nanocomposites foamed by CBA
showed a homogeneously closed-cell structure, suggesting that the
presence of well-dispersed MWNTs plays an important role in
increasing melt viscosity of the nanocomposite so as not to destroy the
cell walls, as well as providing the nucleating sites for cell formation.
We note that the cell size increased with more adding the amount of
CBA, also increasing the temperature. If a proper melt viscosity that
restricts the expansion of cells is established, the cell geometry will be
strongly affected by the aforementioned two factors. From the optical
microscopy data, various morphological parameters of PBS/2 wt%
nanocomposite foams obtained by the SOAM method can be
quantitatively determined, as seen in Table 1. The post-foamed mass
density tended to decrease with an increase in both the CBA content
and temperature as a result of expansion of the PBS nanocomposite
foam, while the neat PBS density is 1.268 g/cm 3 . All nanocomposite
foams exhibit a structure ranging from 154.72 μm to 406.30 μm. The
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