A method of making a HIPP composite comprising blending polypropylene-coated functionalized multiwall carbon nanotubes (PP/f-MWNT) with a first PP to produce a PP and PP/f-MWNT mixture, wherein PP/f-MWNT comprise f-MWNT coated with a second PP via non-covalent interactions, wherein PP and PP/f-MWNT mixture comprises 0.0005 to 5 wt. % f-MWNT, based on the weight of PP and PP/f-MWNT mixture, wherein the first PP and the second PP are the same or different; melt blending the PP and PP/f-MWNT mixture to form a molten PP and PP/f-MWNT mixture; and shaping the molten PP and PP/f-MWNT mixture to form the HIPP composite. A HIPP composite comprising a continuous polymeric phase having dispersed therein a plurality of PP/f-MWNT, wherein the continuous polymeric phase comprises a first PP, wherein PP/f-MWNT comprise f-MWNT coated with a second PP via non-covalent interactions, wherein HIPP composite comprises 0.0005 to 5 wt. % f-MWNT, based on the weight of HIPP.