Montmorillonite-catalyzed furfurylated wood for flame retardancy

Abstract

ABSTRACT 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 the in situ 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.