In this work, hydroxylated HPEEK [poly (ether ether ketone)], which is miscible with the pre-polymer (epoxy), was covalently grafted on to carboxyl functionalized multiwall carbon nanotubes (a-MWNTs) to tailor the interface between MWNTs and the host resin (epoxy). The grafted MWNTs were systematically characterized using spectroscopic techniques. The epoxy composites with a-MWNTs and HPEEK grafted multiwall carbon nanotubes (HPEEK-g-MWNTs) were prepared using mechanical stirring coupled with a bath sonicator to improve the quality of dispersion of the nanoparticles and were subsequently cured at 80 degrees C and 180 degrees C. With the addition of only a small amount (0.5 wt%) of HPEEK-g-MWNTs, an impressive 44% increase in the storage modulus, 22% increase in tensile strength, 26% increase in elongation to failure and 38% increase in fracture toughness was observed with respect to neat epoxy. In addition, the nanoindentation on the composites displayed significant enhancement in the hardness and diminution in the plasticity index. The resultant formulation also facilitated scratch filling ability and resulted in thermally stable coatings/formulations. Such simultaneous improvement in properties was attributed to the improved interface between HPEEK-MWNTs and epoxy matrix. (C) 2016 Elsevier Ltd. All rights reserved.