Understanding the thermal durability of wood-based composites (WBCs) using crack propagation fracture toughness

Abstract

Abstract Wood-based composites (WBCs) are engineered wood products that are commonly used in the building and furniture industries. Most research on their durability has relied on internal bond testing, bending strength properties, or damage observations. An alternative property with potentially more information is fracture toughness. Here, fracture toughness was continuously measured during crack propagation for three different composites—oriented strand board (OSB), medium density fiberboard (MDF), and particleboard (PB). The resulting plots for fracture toughness as a function of crack growth are known as the material’s R curve. To assess the role of temperature on WBC durability, R curve experiments were repeated at 10 different temperatures from 20 to 200 °C. Trends in experimental results could be described by a trilinear model. OSB and MDF toughness initially increased with temperature and then decreased above 80 °C. The toughness of PB, which was made with a different resin, remained constant or decreased slightly until decreasing faster above 140 °C. Both the resin type and composite structure affected the results.