A Biodegradable Bamboo-Based Foam as a Cleaner Alternative to Petroleum-Based Cushioning Materials for Sustainable Fruit Packaging

The proliferation of single-use petroleum-based foams in protective packaging has become a major source of persistent plastic waste, posing significant challenges to environmental sustainability. To address this issue, we developed a fully biodegradable cushioning foam from bamboo, a rapidly renewable biomass, using an environmentally benign deep eutectic solvent (DES) process that avoids harsh chemical bleaching. The resulting lignin-containing cellulose nanofibril (LCNF)/sodium alginate (SA) foam exhibits low density (0.23 g/cm³), high compressive strength (0.24 MPa at 70% strain), and excellent elasticity (90% recovery at 50% strain), enabled by a dual-network structure of Ca²⁺-crosslinked SA and entangled LCNFs. Critically, the material is fully compostable and leaves no microplastic residues, offering a circular end-of-life pathway. In real-world banana drop tests, it matched the performance of commercial expanded polyethylene (EPE) while outperforming polyethylene bubble wrap. This work demonstrates a practical, scalable route to replace fossil-derived cushioning materials with a bio-based alternative that aligns with the principles of cleaner production and circular economy.