Effect of Exchange Reactions and Free Radical Grafting on the High-Speed Reactive Extrusion of Poly Blends

The potential of exchange reactions using titanium butoxide (TBT) as catalyst for the compatibilization of poly(butylene succinate) and poly(propylene carbonate) was explored, and the effects of high speed reactive extrusion on the ester-carbonate exchange reaction were studied. The feasibility of this functionalization route was contrasted to the free radical grafting (FRG) type using maleic anhydride and a peroxide. First, batch mixing and solution blending were conducted to determine the suitable amount of catalyst for blends of this kind. Then, blends at different screw speeds, reaching 1,000 rpm were compounded with catalyst on a twin-screw extruder. Spectroscopy techniques corroborated the formation of block and graft copolymers on the TBT and FRG samples, respectively. Both compatibilization paths produce a positive change in the mechanical properties of the system that was accompanied by a finer droplet size and better interfacial interaction. Specifically, the high-speed runs using a catalyst demonstrated a 177% improvement of the strain at break, proving that the high mechanical energy imparted impacts positively the mixing performance.