Dramatic Improvements in Mechanical Properties of Poly(L-lactide)/Silica Nanocomposites by Addition of Hyperbranched Poly(ester amide)

Biodegradable hyperbranched poly(ester amide) (HBP) was used as a compatibilizer to modify PLA/SiO2 nanocomposites for the first time. The ternary composites displayed dramatically improved mechanical properties including excellent toughness and fairly high stiffness. TEM images revealed that an encapsulation structure was formed by HBP surrounding SiO2 nanopartides, and their surfaces became flocculent due to the migration process of silica. The linear viscoelastic behavior of the nanocomposites measured by parallel plate rheometer indicated that strong interface adhesion existed between PLA matrix and silica nanofiller after incorporating of HBP. The compatibilization effect of HBP and the enhanced mobility of nanoparticles contributed to the improved mechanical properties.