Structural properties of propionylated starch-based nanocomposites containing different amylose contents

This research displayed the structures and thermomechanical feature of starch-based nanocomposites as induced by interaction between propionylated amylose/amylopectin and nanofiller (organically modified montmorillonite). Propionylated amylose incorporated with nanofiller caused some phase separation within the nanocomposites. By contrast, highly-branched propionylated amylopectin favored nanofiller dispersion and disrupted its crystalline structure, and further facilitated certain exfoliated or intercalated structures. Based on these structures, propionylated amylose-rich nanocomposites showed enhanced β-relaxation in the induced "plasticizer-rich" regions, whereas the propionylated amylopectin nanocomposites displayed higher glass-transition temperature due to restricted macromolecular mobility. These results suggested that the structures and further packaging properties of starch-based nanocomposites could be better understood by controlling the interaction of starch with other ingredients.