POLYLACTIC ACID: EXPLORING ITS LIMITS AND OVERCOMING ITS BOUNDARIES

I n a world of continuous technological growth, the discovery of plastic materials was warmly welcomed. Indeed, they opened new possibilities and revolutionized industrial manufacture of everyday life goods. The almost incontrollable growth of polymeric materials industrial production, however, brought along the problem of disposal of end-life plastic objects. The increasing necessity of facing the worrying plastic pollution phenomenon, pushed researchers to find environ- mentally friendly polymers, in order to replace the commonly-used oil-derived ones. Among all biopolymers, polylactic acid (PLA) was found to be one of the most attractive. In particular, PLA monomer, i.e. lactic acid, can be extracted from natural sources and PLA itself is fully biodegradable to unharmful byproducts. Polylactic acid is also character- ized by good processability, but its poor toughness and thermal stability are strong hurdles for its wide industrial applicability. For this reason, PLA-related research is usually aimed at improving its lacking properties, while preserving its good features. The PhD thesis here presented fits in this field. In par- ticular, two strategies were studied, namely the preparation of bionanocomposites and the use of alternative synthetic methodologies. From one side, the use of different cellulose-based nanofillers was investigated and resulted in the production of fully biodegradable and biocompatible nanocomposites with improved properties over standard PLA. On the other hand, O-carboxyanhydrides (OCAs) and 1,3-dioxolane-4-ones (DOX) were studied as alternative monomers for the synthesis of highly functionalized polyester-based materials with tailored properties.