Evaluating the Influence of Specific Mechanical Energy on Biopolymer Blends Prepared via High-Speed Reactive Extrusion

This work studies, for the first time, the influence of specific mechanical energy (SME) on the reaction efficiency and blend’s performance during reactive extrusion of biopolymer compounds. Poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) were compounded separately with poly(propylene carbonate) (PPC) and a premade maleic anhydride (MAH) compatibilizer to achieve functionalization. Different screw speeds (reaching 1000 rpm) and flow rates were tested. Results indicated that the grafting efficiency was directly proportional to the SME imparted in the system. The PBS blends compounded at shorter times and faster speeds experienced less degradation and better mechanical properties than blends compounded at longer times. The effect was similar but less pronounced for the PLA formulations. It is possible to optimize the reactive compatibilization of biopolymer blends by means of SME calculations and that better blend performance is achieved when conducting high-speed extrusion at short residence times.