The development of polymer/graphene-based nanocomposites has opened an interesting area in materials science in recent years and has already found use in industry. However, there are still challenges that must be addressed for these composites to reach their full potential in a wider range of markets. Similar to other nanofillers, dispersion of graphene nanoplatelets is one of the key issues which has a direct effect on the properties of the composites. A comparative study was carried out to investigate the effect of surface treatment/modification of several different commercial forms of graphene nanoplatelets (with or without surfactant, functionalized or not) on mechanical, thermal and morphological properties of polypropylene composites. Surface functionalization techniques were used to provide surface functionalities which enhanced polymer compatibility. Compounds with 1% wt. graphene loading were fabricated by melt compounding in a twin-screw extruder. The efficiency of the graphene addition in polypropylene matrix was verified through measurements of rheological, mechanical and physical properties (rotational Rheometry, DSC, TGA & DMA) as well by morphological and distribution studies (Raman spectroscopy, SEM & optical microscopy).