Enhanced Mechanical Properties and Dimensional Stability of Wood‐Based Composites Through In Situ Chemical Crosslinking

ABSTRACT Wood is a commonly used structural material, widely employed in construction due to its advantages such as lightweight, high strength, thermodynamic properties, and ease of processing. However, its inherent dimensional instability (moisture‐induced shrinkage and swelling), limited mechanical strength, and susceptibility to microbial degradation restrict its broader application. To develop a high‐strength functionalized wood‐based composite, the present work employed an in situ chemical cross‐linking strategy to modify the wood, and the wood‐based composite was prepared with a longitudinal tensile strength of 377 MPa, flexural strength of 428 MPa, and specific strength of 382 MPa·cm ³ g ⁻¹ , which is comparable to that of conventional building materials. Through the in situ chemical crosslinking method, polymerized diphenylmethane diisocyanate (p‐MDI) was introduced into the wood, significantly enhancing its mechanical properties. Moreover, after treatment with acidic and alkaline solvents, the composite retained over 45% of its tensile strength. Additionally, improvements in dimensional stability and resistance to microbial degradation were observed. Characterization techniques such as scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS) confirmed that the distribution of elements and structural changes induced by chemical crosslinking contributed to the enhanced performance. This work advances the mechanical properties, dimensional stability, weather resistance, and antimicrobial performance of wood, providing insights for the development of sustainable, low‐carbon, and renewable construction and structural materials.