Influence of Silica Size on Properties of Poly[(Butylene Succinate)-Co-Adipate]/Butyl-Etherified High-Amylose Starch Blend Composites

In this study, hydrophilic microsilica and nanosilica particles are dispersed in poly[(butylene succinate)-co-adipate]/butyl-etherified high-amylose starch (PBSA/BHAS) blends in order to stabilize the morphology by refining the droplet sizes of BHAS phase. The composites are prepared through melt processing in a batch mixer at varying screw speeds. Scanning and transmission electron microscopy studies confirmed the dispersion and localization of microsilica particles in the PBSA matrix and nanosilica particles in the dispersed BHAS phase. The increase in the screw speed promoted migration of some microsilica particles from the PBSA matrix to the dispersed BHAS phase, while nanosilica particles are mostly localized in the BHAS phase at both screw speeds. This led to changes in viscosity ratios that resulted in a variation in the morphology development. In conclusion, PBSA/BHAS blend composites containing both micro- and nanosilica particles are studied and a correlation between the silica particle sizes, localization, and the final properties was established.