Sustainable valorization of bamboo residues: Self-bonding nano fibrillation strategy enabling adhesive-free bamboo composites

Abstract

The efficient utilization of bamboo residues is of great significance for improving resource utilization and reducing environmental pollution. This study pioneered a self-bonding nanofibrillation strategy for high-performance bamboo composites without the need for additional additives, effectively upcycling bamboo residues into high-performance engineering composites. The breakthrough methodology leveraged bamboo's inherent binding potential via a three-stage process: (1) ultra-precision particle size optimization, (2) initial moisture content regulation, and (3) thermos-compression via self-bonding activation through ultrastructural chimerism and chemical bonding. The results showed that the particle size and initial moisture content had significant effect on the self-bonding activation of bamboo. The obtained binderless bamboo composites (BBC) exhibited superior water resistance and enhanced strength when the particle size of bamboo residues was 60 mesh and the initial moisture content was 10 %, with a 24-hour water absorption thickness swelling of 1.04 %, a MOE of 6.5 MPa, a hardness of 24.2 kgf/mm², all much more excellent than those observed in traditional wood-based panels. This study established the process-structure-property relationship for self-bonding behavior of bamboo, providing both fundamental understanding of lignocellulosic self-bonding mechanics and scalable methods for the production of formaldehyde-free composites. The technology achieved 100 % utilization efficiency of bamboo residue, positioning it as a transformative solution for sustainable materials and the advancement of circular bio-economy.