Large-scalable production of sustainable, degradable and recyclable bird-nest-like foam via bamboo cell reassembly and direct atmospheric drying

The global shift towards sustainable development has raised concerns over traditional plastic foams due to their high energy requirements, petroleum dependency, and persistence in the environment. Lignocellulose-based foams offer a promising alternative, but their production remain time-consuming, environmentally unfriendly, energy-intensive, and costly, restricting their scalability. In this work, a sustainable bamboo foam with a lightweight (0.052 ± 0.001 g/cm³), highly porous (91.63 %) structure, was fabricated by partially removing lignin and hemicellulose from bamboo sawdust through a rapid (20 min) delignification treatment, and then reassembled bamboo cells via draining and atmospheric drying. The resulting foam exhibits low-shrinkage (8.83 %), exceptional mechanical performance (compressive strength of 1.0 MPa at 60 % strain) and low thermal conductivity (0.037 W/(m·K)), as the retained lignin strengthens the porous network and preventing structural collapse during drying. Additionally, the bamboo foam exhibits outstanding biodegradability, recyclability, and sustainability, significantly mitigating environmental impact of discarded insulators. Life-cycle and economic cost analysis reveal that its global warming potential and market selling prices are considerably lower compared to those of traditional commercial plastic foam (polystyrene (PS), polypropylene (PP), expanded polyethylene (EPE), and polyurethane (PU)). Therefore, this work provides a scalable pathway for producing sustainable bamboo foams, demonstrating potential in advancing eco-friendly material solutions. • The foams were produced via atmospheric drying without solvent displacement. • The produced foam exhibited lightweight (0.052 g/cm³) and high porosity (91.63 %). • Excellent thermal insulation and mechanical properties were achieved. • The foams demonstrated excellent environmental benefits and cost-effectiveness.