Biodegradable polymers are raising an increasing interest as a promising alternative to petroleum-based materials since they can be produced from renewable resources at reasonable costs. Among all the possible biodegradable polymers, the most commonly studied is poly(lactic acid) (PLA). However, PLA has some processing limitations such as poor thermal and mechanical resistance and slow crystallization kinetics, if compared to other thermoplastic resins, which prevent its complete access to industrial sectors. Carbon materials have gained a new significant attention as a filler to enhance polymer properties: in this work graphite, carbon black, and an ad-hoc functionalized carbon black application is investigated. These carbon-based materials were melt compounded in a twin screw extruder with different mixing times and characterized by differential scanning calorimetry (DSC), rotational rheometry and GPC tests. Experimental results show that the compounds exhibit a lower crystallization time, if compared to the neat resin, and a good thermo-mechanical stability. In particular, the functionalized carbon black shows the fastest crystallization kinetics, probably due to a specific nucleation effect of the functional tails.