Abstract:
Polylactide/butylated-starch/nanoclay (70/25.5/4.5 wt%) composites were prepared by melt blending
with nanoclays of varying hydrophobicity. Electron microscopy studies indicated that the interphase
boundary interaction was highest in the clay with intermediate hydrophobicity but decreased with clays
of higher or lower hydrophobicity. Conventional and modulated differential scanning calorimetry studies
showed that, in the case of composites, the change in the ratio of rigid and mobile amorphous fractions
depends on the hydrophobicity of clays used for the preparation of blend composites. The mobile
amorphous fraction related to the polylactide phase decreases in the case of intermediate hydrophobic
clay compared with less and more hydrophobic clays or neat blend samples. Avrami bulk crystallization
analysis and polarized optical microscopic observation demonstrated that hydrophobic clays hindered
the crystallization of the PLA phase into the formation of disc-shaped spherulites. On the basis of obtained
results, we propose a general understanding on how the morphology and thermal properties of
the blend composites are related to the hydrophobicity of the nanoclays.
