Talc and talc modified with trimethoxy(octadecyl)silane (O-talc) were melt compounded with poly (L-lactide) (PLA). The crystallization behavior, tensile properties, and impact strength of the PLA composites were examined before and after the incorporation of talc and O-talc. The molecular weight of PLA in the PLA composites was measured as a function of the hydrolysis time and temperature. The effect of talc and O-talc on the thermal stability of PLA was examined and quantified by the activation energy of thermal degradation and the integral procedural decomposition temperature value determined from the corresponding thermo-gravimetric analysis weight loss profiles. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013