Eco-friendly and practical plastic food-packaging alternatives of all-biomass-derived nanocomposite films

Abstract

Approximately 60% of plastic pollution originates from the food and beverage packaging. Complete degradation of the bio-based plastic packaging presently available, relies on garbage sorting, recycling, and composting. Herein, we showcase that naturally-degradable bioplastics as food packaging alternatives can be accomplished with all-biomass nanocomposite encompassing pullulan, nanocellulose (NC) and/or hydrophobic lignin (HBL) using simple approaches. NC and HBL were derived from corn stalk using a recyclable eco-friendly deep eutectic solvent (DES). Optimal dispersion of NC in pullulan through high-pressure homogenization produced a pullulan-NC (PNC) bio-nanocomposite film with mechanical strength enhanced to 76.6 ± 1.9 MPa. Single PNC film could serve as food inner-packaging; while it collaborated with kraft paper wrapping to compensate its inadequate water resistance, performing as packaging for dry powders, biscuits, and oil. Remarkably, a sandwich-like film, created by hot-pressing two outer layers of HBL-NC (LNC) films and one PNC film layer, exhibited desirable mechanical strength and water resistance. Varying the number of LNC and PNC layers achieved diverse composite films as food outer-packaging, including preserving and shopping bags, disposable cups and straws. Significantly, all these films are biosafe and readily degraded in nature without counting on composting or recycling, underlining their prospects in future industrialization and sustainability.