Morphology and rheological behavior of polylactic acid/clay nanocomposites

The investigated rheological properties of polylactic acid (PLA)/clay nanocomposite are important to understand the effect of organically modified layered silicates (OMLS) (clay) on processing as well as the change in viscoelastic properties due to polymer filler interaction. The time sweep result revealed that the thermal stability improved with addition of nanoclay due to the formation of percolating network structure. It was also supported by multi wave ramp test. The frequency sweep analysis showed that the dynamic moduli increased with addition of nanoclay. Viscoelastic spectra (DMTA) showed an increase of the storage and loss moduli with the increase in the clay content. Wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) were used to determine the degree of intercalation, or exfoliation and nanostructure level of clay dispersion on PLA nanocomposites. XRD data demonstrated complete exfoliation at lower nanoclay content. On increasing the nanoclay content, exfoliated and partially intercalated structures were obtained.