Nanocomposites containing thermally reduced graphene (TRG) have been prepared with poly(trimethylene terephthalate) (PTT) plasticized with (bisphenol-A diglycidyl ether) (BADGE), a cross-linkable additive. Morphology of the PTT-BADGE blend was dependent on preference for interaction of TRG with PTT or BADGE and nucleation activity of TRG toward PTT. PTT-TRG and PTT-BADGE-TRG nanocomposites with different BADGE-TRG ratios were prepared by a melt mixing technique facilitated by miscibility of PTT and BADGE. The influence of TRG on crystallization nucleation, kinetics and morphology was measured using differential scanning calorimetry and wide-angle X-ray scattering. Crystallization of PTT caused phase separation of BADGE, though PTT-BADGE remained miscible in PTT amorphous regions. BADGE created increased flexibility of PTT though dynamic mechanical properties were moderated by TRG, both directly as a filler and as a result of enhanced crystallization. Synergistic improvement in modulus was observed at particular compositions attributed to a change in morphology of an immobilized zone consisting of BADGE and TRG within amorphous fractions of PTT. The results are of consequence for design of materials using a semi-crystalline polymer, for applications where simultaneous use of a processing aid, plasticizer and nano-reinforcement. (C) 2016 Elsevier Ltd. All rights reserved.