A one-pot silane-bridge strategy for synergistic wood modification: improving cinnamaldehyde fixation, mold resistance, and dimensional stability

Abstract

Eco-friendly small-molecule natural products hold great potential for improving wood properties; however, their application is limited by susceptibility to leaching and restricted functionality. To improve the fixation of these compounds within wood and achieve a synergistic improvement in both antifungal performance and dimensional stability, cinnamaldehyde was grafted onto the cell wall of poplar (Populus × euramericana ‘I-69’) wood via a one-pot process mediated by (3-aminopropyl)triethoxysilane (APTES). The retention of cinnamaldehyde in modified poplar wood was evaluated based on its leached and volatile mass. The mold resistance was assessed according to anti-mold efficacy following leaching tests. The dimensional stability was assessed by measuring moisture content and dimensional changes during hygroscopic and drying processes. Additionally, the modified wood was characterized using the Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), and Scanning electron microscopy (SEM). The results demonstrated a significant improvement in the leaching resistance of cinnamaldehyde and the anti-mold stability of the modified wood. The leached and volatile mass of cinnamaldehyde were reduced by more than 90%. Consequently, the anti-mold efficacy of modified wood after leaching was more than 70%. Dimensional stability of modified wood was significantly improved, manifested by a reduction of over 40% in the volumetric swelling coefficient (VSWC). The moisture exclusion efficiency (MEE) and anti-swelling efficiency (ASE) reached 25.9% and 56.0% under air-dried conditions, and 8.1% and 41.1% under water-saturated conditions, respectively. The characterization confirmed that cinnamaldehyde was grafted onto wood hydroxyl groups via Schiff base and condensation reactions mediated by APTES. This study achieved a synergistic improvement in mold resistance, leaching resistance, and dimensional stability, thereby extending the potential application of small-molecule aldehyde natural products in wood modification.