How microwave puffing regulates the hygroscopic response of non-carbonized bamboo residues toward sustainable...

Bamboo residues and short culm wastes are increasingly recognized as promising renewable resources for developing high-performance, sustainable materials in construction, energy, and transportation. However, their high hygroscopicity severely limits dimensional stability and long-term reliability. To address this challenge, this study investigates the regulation of hygroscopic response in non-carbonized puffed Moso bamboo residues through microwave-driven structural reconstruction, aiming to promote cleaner production and waste valorization. Results showed that equilibrium moisture content declined from 16.2 % in the control to 11.4 % under strong puffing, while hysteresis area narrowed by 28.6 % and anti-swelling efficiency rose from 12.5 % to 41.7 %. Hemicellulose loss (≈50 %), cellulose reduction (>20 %), and lignin enrichment were accompanied by a decrease of the O/C ratio from 0.8470 to 0.6304, indicating a hydrophobic transformation of the cell wall. These changes could be driven by hydrogen-bond network disruption, polysaccharide degradation, and lignin stabilization. Microwave puffing thus provides an effective, low-emission strategy to enhance dimensional stability, extend service life, and achieve high-value reuse of bamboo waste, contributing to cleaner production and long-term carbon retention.