Sequential Dual‐Curing via Michael Addition and Free Radical Polymerization for Wood Surface Densification

ABSTRACT The application of sequential dual‐curing systems involving Michael addition and free radical polymerization has shown promise for enhancing polymeric networks' thermal and mechanical properties. This study investigates a dual‐curing approach for the surface densification of wood, a technique that can expand wood applications by increasing surface density and hardness. A two‐step curing process was explored by leveraging the versatility of bio‐based acrylate‐ and malonate‐based formulations. The curing kinetics of this system based on carbon Michael addition followed by photopolymerization (UV)—were analyzed using real‐time Fourier transform infrared spectroscopy and photo‐differential scanning calorimetry. Additionally, polymer properties were evaluated through dynamic mechanical analysis and pendulum hardness experiments. Results for dual‐curing systems revealed superior conversion rates, glass transition temperatures, and crosslinking densities compared to a single‐cured Michael addition system. The study also assessed the effectiveness of various formulations and impregnation procedures, including the use of vacuum pressure, to optimize the densification process. The findings demonstrated that the dual‐curing approach significantly enhances surface hardness, offering a rapid method with the potential for cost‐effectiveness and environmental friendliness in wood densification.