Recyclable grease-proof cellulose nanocomposites with enhanced water resistance for food serving applications

Abstract

Recyclable cellulose nanofibril (CNF) and lignin-containing cellulose nanofibril (LCNF) coated wood flour composites were fabricated using a vacuum-filtration process for food serving applications. The coated cellulose nanofibril composites had excellent mechanical, and oil, and grease barrier properties compared to a commercial container. However, the composites with both LCNF and CNF coating layers had poor performance in wet conditions compared to the commercial container. The addition of 1 wt.% aluminum sulfate (alum) to the CNF and LCNF coating layer significantly improved the water-resistance of the composites. CNF + 1% alum coated composites had inferior water resistance and lower mechanical strength in wet conditions compared to the commercial container. However, the LCNF + 1% alum coated composites had comparable water resistance and higher wet mechanical properties than the commercial container. The recyclability of the composites was assessed through the disintegration of the samples in water and subsequent reformation, and it was found that the composites were fully recyclable. The composites could fully retain their mechanical and excellent oil and grease barrier properties after each recycling level. These recyclable fully bio-based nanocomposites can be an eco-friendly alternative for currently used food container systems that use harmful chemicals.Graphical abstract