Surface degradation of wood scrimber under accelerated UV-hydrothermal cycling

The degradation mechanisms of wood scrimber under multifactorial environmental stress remain incompletely understood. In this study, poplar wood scrimber was subjected to cyclic accelerated aging tests. Comparative analyses were performed on samples before and after treatment to assess key surface characteristics, including color change, roughness, wettability, micromechanical properties, and chemical composition. The research reveals the underlying degradation mechanisms responsible for surface deterioration, the decline in micromechanical performance, and the breakdown of chemical constituents in wood scrimber under combined UV and hydrothermal exposure. The results indicated that the accelerated aging process led to a darkening and roughening of the wood scrimber surface, accompanied by the loosening of its fibrous structure. Concurrently, the chemical components exhibited differential degradation rates. As the PF resin itself degraded, its supportive role in the cell wall was diminished, resulting in reductions of 41.3 % in HIT and 40.8 % in Er of the cell wall after 240 h of aging. • Surface degradation of wood scrimber was investigated under UV-hydrothermal cycling. • PF resin migrates into cell lumens forming temporary protective films during mid-stage aging. • Synergistic UV-hydrothermal cycling degrades resin/lignin first, then cellulose mechanics.