Bisphenol-A polycarbonate (PC) and multi-walled carbon nanotubes (MWCNTs) functionalized with hydroxyl groups were melt mixed in a twin extruder to produce PC composites containing PC-grafted MWCNTs (PC-g-MWCNTs) by reacting hydroxyl groups on MWCNTs with the carbonate groups in PC. Formation of PC-g-MWCNTs by reactive extrusion was explored as were their resulting properties including interfacial adhesion energies between PC and MWCNTs, dispersion of MWCNTs in the PC matrix and mechanical and electrical properties of PC/MWCNT composites. The interfacial adhesion energy of the PC/PC-g-MWCNT composite was higher than that of the PC/pristine MWCNT composite; as a result, the PC/PC-g-MWCNT composite exhibited a higher level of dispersion of MWCNTs in the PC matrix and better adhesion at the interface between PC and MWCNTs than the PC/pristine MWCNT composite. For a fixed MWCNT content in the composite, the mechanical strength of the PC/PC-g-MWCNT composite was higher than those of the corresponding PC/pristine MWCNT composite. (C) 2015 Elsevier Ltd. All rights reserved.