Reactive Extrusion as an Environmentally Friendly Technology for the Production of Bio(Nano)Composites: Implementation and Characterization

Abstract

The influences of reactive extrusion of poly(lactic acid) (PLA)-based bio(nano)composites on their properties are described. Reactive compatibilizers were used to enable good dispersion of natural (nano)fibers in the thermoplastic matrix consisting of PLA/poly(butylene adipate-co-terephthalate) (PBAT) and PLA/polycarbonate (PC) blends. At the same time, chain extenders were used for the modification of immiscible thermoplastics, PLA and PBAT, in order to achieve good miscibility of the PLA/PBAT blend. In the experimental part, the main obstacle of PLA, its brittleness, was improved in three different series of bio(nano)composites. Reactive extrusion with PLA/PBAT blends and the addition of hops as a chain extender and compatibilizer increased the elongation at break of the bio(nano)composite by more than 240% and the impact strength by 200% compared to neat PLA. Reactive extrusion of PLA/PBAT blends and addition of 1% nanocrystalline cellulose (NCC) with additives increased the elongation at break by more than 730% compared to pure PLA, and the sample did not break during the impact testing. Reactive extrusion with PLA/PC blends and the addition of 1 wt% NCC with additives increased the elongation at break by more than 90% and the impact strength by more than 160% compared to pure PLA.