Modification of poly(lactic) acid by reactive extrusion and its melt-blending with acrylonitrile butadiene styrene

Poly(lactic) acid, (PLA) is a biodegradable polymer that has attracted interest as a potential substitute for some thermoplastic polymers. However, its advanced brittleness at room temperature represents one of the major drawbacks for its general use. In this work, PLA was modified by reactive extrusion (PLAREx) to enhance the rheological behavior and to limit its degradation. The modified material was melt blended with ABS, analyzing the resultant morphology, rheological, thermo-mechanical and fracture behavior. Since PLA does not have reasonable compatibility with ABS, maleic anhydride-grafted ABS (ABS-g-Ma) was used as compatibilizer. The morphology of the PLAREx/ABS samples resulted in the formation of small ABS rods in the matrix. The presence of maleic anhydride contributed to reduce the interfacial energy of the blends and to obtain finer micro-domains of the ABS-rich phase in the PLAREx matrix. In the compatibilized blends, the presence of elongated ABS-rich phases opposed the free crack propagation and contributed to the increase in the fracture energy in comparison to neat PLA.