Investigation of thermo-mechanical, chemical and degradative properties of PLA-limonene films reinforced with cellulose nanocrystals extracted from Phormium tenax leaves

Poly(lactic acid) (PLA) bio-nanocomposite films modified with limonene as plasticizer and reinforced with cellulose nanocrystals (CNC) extracted from agro-waste, such as Phormium tenax leaves, have been prepared by using a twin-screw microextruder and characterized. The extraction of cellulose was carried out by chemical treatment followed by sulphuric acid hydrolysis process. Binary and ternary films containing the plasticizer (20 wt.%) and/or the CNC (1 and 3 wt.%) were produced and characterized in terms of morphological, thermal, mechanical and wettability properties. The effect of CNC content and the combination with the specific plasticizer on the structural properties of PLA films were also investigated. The addition of limonene into the PLA matrix reduces, as expected, the glass transition temperature of the films, and affects the mechanical properties of the films, increasing the plastic response of PLA. Disintegration study was also carried out under simulated composting conditions in a laboratory-scale test at 58 °C, 50% of humidity and in aerobic conditions, demonstrating that the presence of both plasticizer and CNC can alter the degradation rate of developed PLA-based formulations. The successful production of PLA biodegradable nanocomposites incorporating cellulosic material from agro-waste suggested the possible application of these new bio-nanocomposites for active food packaging.