From lignin to high performance coatings: UV curing of bisguaiacol-derived resins and hybrid organic–inorganic coatings

This study reports the development of sustainable UV-curable coatings based on lignin-derived aromatic building blocks. Bisguaiacol F (BGF) isomers obtained from vanillyl alcohol and guaiacol were functionalized to produce bisguaiacol-F-diacrylate (BGF-DEDA) and bisguaiacol-F-diglycidyl ether (BGF-DGE), which were evaluated in both pristine formulations and hybrid systems containing tetraethyl orthosilicate (TEOS). The photopolymerization behavior of the formulations was investigated, revealing different reactivity trends depending on the curing mechanism. The use of dual-curing strategies enabled effective formation of an inorganic silica network. Dynamic mechanical thermal analysis (DMTA) and field emission scanning electron microscopy (FESEM) confirmed the in-situ generation and homogeneous dispersion of silica nanoparticles, which significantly restricted polymer chain mobility. As a result, hybrid materials exhibited notable improvements in thermomechanical performance, with glass transition temperatures reaching up to 106 ◦C and surface hardness values up to 8H in epoxy-based coatings. Overall, these results demonstrate the potential of lignin-derived aromatic platforms for designing high-performance bio-based hybrid coatings with tunable properties, offering promising prospects for advanced protective coating applications.