ORIGINAL PAPER Thermal stability and thermal degradation kinetics (model-free kinetics) of nanocomposites based on poly (lactic acid)/graphene: the inﬂuence of functionalization Pedram Manaﬁ • Ismaeil Ghasemi • Mohammad Karrabi • Hamed Azizi • Mohammad Reza Manaﬁ • Parvin Ehsaninamin Received: 26 June 2014 / Revised: 24 January 2015 / Accepted: 2 February 2015 Ó Springer-Verlag Berlin Heidelberg 2015 Abstract Thermal stability and thermal degradation kinetics of nanocomposites play an important role in many applications. In this study, nanocomposites based on poly (lactic acid) (PLA)/graphene containing 0.5 and 1 wt% were prepared via solution method. Functionalized graphene were prepared by acid treatment followed by grafting PLA on their surfaces. The functionalized graphene was characterized using fourier transform infrared spectroscopy (FTIR), Raman, elemental analysis, Fourier transform infrared attenuated total reﬂection (FTIR-ATR), Dynamic me- chanical thermal analysis (DMTA) and thermogravimetry analysis (TGA). The results revealed a successful functionalization reaction. The morphology of nanocomposites was investigated by scanning electron microscopy (SEM). Thermal kinetics of samples was studied using TGA in multiple heating rates (5, 10, 20 and 30 °C/min). Flynn–Wall–Ozawa (FWO) and Vyazovkin (VYZ) methods were considered as isoconversional models. Although the assumptions of the applied models were different, there was a good agreement between the models and ob- tained activation energies. Keywords Polymers  Nanostructures  Thermal properties  Thermogravimetry analysis P. Manaﬁ  I. Ghasemi (&)  M. Karrabi  H. Azizi Plastic Department, Iran Polymer and Petrochemical Institute, P.O.Box: 14965/115, Tehran, Iran e-mail: i.ghasemi@ippi.ac.ir M. R. Manaﬁ Department of Applied Chemistry, Islamic Azad University, South Tehran Branch, Tehran, Iran P. Ehsaninamin Faculty of Chemistry, Tehran North Branch of Islamic Azad University, Tehran, Iran 123 Polym. Bull. DOI 10.1007/s00289-015-1325-4 Downloaded from http://www.elearnica.ir