Montmorillonite-catalyzed furfurylated wood for flame retardancy

Flammability, as an undesirable inherent nature of wood, limits its usage in many fields of structural applications. Hybrid organic-inorganic modification offers a way to improve the flame retardancy of wood. In this study, montmorillonite (MMT)-catalyzed furfurylated wood was prepared by polymerization of furfuryl alcohol (FA) with hydrogen-MMT (H-MMT) used as catalyst. Poplar wood ( Populus cathayana Rehd. ) was delignified at first to increase its nanoporosity, and then impregnated with H-MMT/FA suspensions, followed by curing at 105 °C to form the MMT-catalyzed fufurylated wood hybrids. The H-MMT/FA suspensions were dispersed in the cell walls and cell lumens of delignified wood. The acidic catalyst, H-MMT, catalyzed in situ the polymerization of FA in wood, restrained the smoke emission of FA and provided catalytic sites for char formation under combustion. Additionally, H-MMT sheets can be used as an effective flame retardant due to its thermal and gas barrier properties . Cone calorimeter test showed that the total heat release of modified wood was decreased by 29% compared with original wood. The modified wood exhibited excellent flame retardancy by reducing the amount of flammable gases and impeding the diffusion of heat.