Poly(lactic acid) (PLA) has received great attention as an eco-friendly polymer because of its competitive price and high strength as well as being renewable and biodegradable. However, neat PLA cannot meet the requirements in some special circumstances because of its inherent brittleness; thus, toughening is required [1]. Thermoplastic polyurethanes (TPUs) can be used to toughen PLA by melt blending [2]. Polyhedral oligomeric silsesquioxanes (POSS) organic/inorganic hybrid materials are nanoparticles containing functional groups that are potential sites for polymerization, grafting, surface bonding etc. Epoxy POSS nanoparticles can react with carboxylic acid and isocyanate end-groups of either PLA or TPU in a wide temperature range [3]. Therefore, it can be used as a compatibilizer for PLA/TPU system. The objective of this study is to observe the effects of TPU content on the thermal and thermo-mechanical properties of PLA/TPU/Epoxy-POSS ternary blends. Blends were prepared by melt compounding process using an Xplore Instruments laboratory compounder. Thermal and thermo-mechanical properties were examined. The results showed that increasing TPU content inclined thermal decomposition temperatures of blends. In addition glass transition temperatures and crystalinity behaviours showed differences according to TPU content. Besides, thermo-mechanical properties showed that storage modulus decreased in case of higher TPU content. Acknowledgement: This study is financially supported by TUBITAK (Grant Number: 115M576) References [1] Madhavan Nampoothiri, K.; Nair, N. R.; John, R. P., Research.Bioresour.Technol., (2010), 101, 8493−8501. [2] Han J. J., Huang H. X., Jour.of Appl.Polym. Sci., 2011(120), 3217–3223. [3] Li G., Wang L., Ni H., C. U. Pittman, Journ.of Inorg.and Organomet. Polym., 2001(11-3), 123-54.