Green Processing Route for Polylactic Acid–Cellulose Fiber Biocomposites

A completely green approach was adopted for the production of biocomposites of polylactic acid (PLA) and cellulosic fibers (CF) via functionalization of CF with an aqueous solution of poly­(ethylene oxide) (PEO) followed by extrusion with PLA and injection molding. The treatment with PEO improved the interfacial interaction among the components as well as the CF dispersion and free flow upon extrusion, allowing loading up to 30 wt % of CF. Moreover, the synergistic effect of PEO and CF greatly enhanced the physical–chemical properties of the biocomposites. Their storage modulus was higher with respect to pure PLA in the rubbery region. The stiffness and mechanical strength were found to be higher than those of PLA/PEO and remained comparable to pure PLA, whereas the elongation at break was 73–143% higher owing to the effective plasticizing and reinforcing effect exerted by PEO and CF respectively. Addition of PEO and CF had a great influence on the thermal properties, particularly on the glass transition and cold crystallization temperatures. Overall, the appealing properties of the proposed biocomposites combined with the sustainability of the developed process render them ideal for several technological applications within the plastic industry including food and cosmetic packaging, disposable items, and toys.