Dual preservative strategy for facilitating bamboo durability using cinnamaldehyde and diethylenetriamine and its reaction characteristics on bamboo cell wall

Cinnamaldehyde exhibits excellent anti-mold properties that can preserve bamboo. However, establishing a stable bonding linkage (C--N) requires cinnamaldehyde modification, which can be used to manipulate cell wall characteristics and improve bamboo durability. In this study, cinnamaldehyde's chemical fixation into bamboo through the Mannich reaction was successfully achieved, resulting in enhanced anti-mold capacity and dimensional stability. The modified bamboo exhibited remarkable anti-mold properties, with a 40.0% increase in resistance to swelling caused by moisture fluctuations. Nanoindentation analysis also revealed that the internal bamboo cell wall's mechanical properties improved following modification, including a significant improvement in surface hydrophobicity from 13.9 degrees to 67.3 degrees. Concerning the impact of the modification on bamboo cells, the sclerenchyma cell of bamboo was determined to be the focus. We used guaiacol as a lignin model compound to elucidate the potential mechanism of cinnamaldehyde modification, specifically Schiff base formation, using nuclear magnetic resonance spectra. This study shows a viable dual preservative strategy to extend bamboo lifespan.