The properties of reactive polymer blends are strongly influenced by the interchange/exchange reactions The effect of nanofillers on these reactions in particular transreactions has not yet fully understood This work is devoted to investigate transesterification and its consequent effect on degradation behavior of phenoxy/poly(trimethylene terephthalate) (PIT) nanocomposites using thermal analysis techniques H-1 NMR results showed that the maximum extent of transreactions occurred in the blends loaded with Just 1 wt % nanoclay A mechanism based on nanoconfinement was proposed to show how nanoclay particles affect ransreactions of the blend constituents Thermal degradation kinetic studies using KAS isoconversion method revealed that addition of only 1 wt % clay Improves thermal stability of the pristine blend whereas higher amount of clay accelerates degradation process An attempt was made to establish correlations among these changes in thermal degradation behavior the extent of transreactions and dynamic mechanical properties (C) 2010 Elsevier B V All rights reserved