Bionanocomposites based on poly(3-hydroxybutyrate) (PHB) and starch plasticized with glycerol and water thermoplastic starch (TPS) with organically modified montmorillonite clay as a nanofiller were obtained by melt-blending. The influence of the clay and TPS on the thermal and mechanical properties of the resultant bionanocomposite was investigated by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis, differential scanning calorimetry, and nanoindentation. The results obtained by AFM showed that bionanocomposites have a surface roughness of 30.88nm, compared to 14.53nm for processed PHB. This result is obtained due to the migration of clay layers to the surface. From XRD and TEM it was determined that the clay layers of the bionanocomposites are completely separated. The hardness and elastic moduli of bionanocomposites have values similar to those of PHB, improving the drawbacks of the PHB-TPS blends (65:35 weight ratio). The thermal properties do not present significant changes, and only the degree of crystallinity decreased with increasing clay content. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45217.
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