Two commercially available bio-based PLA grades were supplied from NatureWorks LLC, USA: Ingeo 4043D and Ingeo 3251D, with melt flow index (MFI, at 210°C with 2.16 kg) of 6 g/10min and 80 g/10min, respectively. The samples, both having densities of 1.24 g/cc, were designated as HPLA and LPLA, respectively, for high and low molecular weight. The commercial NC (Cloisite 30B, ∼6-13 µm) was provided by Southern Clay Products, Texas, USA, and commercial GNP (xGnP M-5, ∼5 µm) were purchased from Sigma-Aldrich Chemical Co. Both nanoparticles were used without any surface treatment.