Carbon-based nanoparticles (namely fullerenes, carbon nanotubes, exfoliated graphite nanoplates and graphene) have unique electrical, thermal, barrier and mechanical properties, which makes them potentially suitable for a wide scope of advanced applications. When incorporated into polymer matrices, the properties of the resulting nanocomposites are strongly determined by the level of dispersion achieved as well as by the degree of polymer/particle interfacial bonding. Both can be improved through chemical modification of the carbon surface by covalent or non-covalent approaches. The mixing protocol utilized and the set of operating conditions selected are equally important. Melt mixing routes are attractive, as they allow straightforward scale up to industrial production. However, so far the performance of most nanocomposites containing graphene or graphene derivatives produced by melt mixing has been disappointing, or can only be attained with unexpectedly high filler contents. Therefore, it is important to better understand the mechanisms of dispersion of carbon-based nanoparticles in thermoplastic matrices and their influencing factors. This work describes the evolution of the dispersion of graphene nanoplates during compounding in a co-rotating twin screw extruder fitted with sample collecting devices along its axis and subsequent single screw extrusion in a machine with identical sampling capacities. Thus, by monitoring the evolution of dispersion in the two successive thermo-mechanical cycles usually adopted in industrial practice, a better understanding of the kinetics and stability of dispersion should be achieved. Two commercial graphite nanoplates (xGnP) were chemically modified via 1,3 dipolar cycloaddition and grafted with PP-g-MA (fxGnP-PP). Pre-mixes containing 2 or 10 wt. % of xGnP and fxGnP-PP were then utilized in this study.