This work aims at preparing and characterizing poly(butyl acrylate) (PBA)laponite (LRD) nanocomposite nanoparticles and nanocomposite core (PBA-LRD)-shell poly(methyl methacrylate) (PMMA) nanoparticles, on the one hand, and the morphology and properties of poly(lactic acid) (PLA)-based blends containing PBA-LRD nanocomposite nanoparticles or (PBA-LRD)/PMMA core-shell nanoparticles as the dispersed phase, on the other hand. The PBA and (PBA-LRD)/PMMA nanoparticles were synthesized by miniemulsion or emulsion polymerization using LRD platelets modified by 3-methacryloxypropyltrimethoxysilane (MPTMS). The grafting of MPTMS onto the LRD surfaces was characterized qualitatively using FTIR and quantitatively using thermogravimetric analysis (TGA). The amounts of LRD in the PBA-LRD nanocomposites were characterized by TGA. The PBA/PMMA core-shell particles were analyzed by 1H-NMR. Their morphology was confirmed by SEM and TEM. Mechanical properties of (PBA-LRD)/PLA blends and (PBA-LRD)/PMMA/PLA ones were tested and compared with those of the pure PLA, showing that core-shell particles allowed increasing impact strength of the PLA while minimizing loss in Young modulus and tensile strength. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013