Fire performance of oak wood modified with N-methylol resin and methylolated guanylurea phosphate/boric acid-based fire retardant

Modification with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) can dimensionally stabilize wood and improve the durability, but does not change its flammability. In this study, fire retardant (methylolated guanylurea phosphate (MGUP) and boric acid (BA)) was incorporated in DMDHEU to treat Oak wood (Quercus rubra L.). Thermogravimetry and cone calorimetry showed that combinative treatment with DMDHEU/MGUP/BA caused a considerable decrease in the pyrolysis temperature, heat release, and smoke production. A full-scale fire test indicated that DMDHEU/MGUP/BA modified wood can be classified as Bfl-s1. Findings demonstrated that combinative treatments can substantially reduce the fire risk for DMDHEU-modified wood, making them especially useful for application in public settings.