Both the thermal behavior and kinetic decomposition of starch-g-poly(phenyl methacrylate) copolymers were studied by the TG/DSC/FTIR/QMS coupled technique under inert conditions. In order to compare the results, potato starch was used as a reference material. The results indicate that the thermal degradation takes place in two large stages: (i) destruction of the molecular polysaccharide blocks at temperatures <= 300 degrees C and (ii) structural graft depolymerization from 320 to 440 degrees C. The kinetic analysis in terms of E(alpha) on alpha indicates that during the initial stage, with activation energies ranging from 140 to 205 kJ mol(-1), a two-step reaction mechanism involving two consecutive reactions takes place, an initial endothermic reversible reaction followed by an irreversible one, which is related to the cracking of the starch glycosidic bonds. Meanwhile the degradation analysis of the graft polymer reveals that the stage involves several overlapping steps with average activation energies between 120 and 180 kJ mol(-1). (C) 2015 Published by Elsevier B.V.