Enhancing Toughness of Medium-Density Fiberboard by Mimicking Nacreous Structures through Advanced Manufacturing Techniques

Medium-density fiberboard (MDF) is widely used in building construction. Due to its inherent brittleness, MDF is typically employed in nonstructural components such as partition walls. Many structures found in nature are also composed of brittle materials, but their unique structural arrangements provide superior mechanical performance to traditional engineering construction. An excellent example is nacre, a tough component of the armor system of mollusk seashells. The masonrylike structure of nacre is mainly composed of a brittle ceramic mineral, but its toughness is several orders of magnitude greater than aragonite. Herein, MDF is toughened using principles inspired by nacre. Several of the structural features of nacre are mimicked, namely (1) the polygonal bricks and reinforcing bridges between them to control strength, and (2) the highly deformable polymeric mortar to control toughness. The process of manufacturing the nacrelike MDF composite panel is automated using a computer-generated Voronoi geometry and laser cutting. The performance of the nacrelike panel is experimentally assessed under quasi-static tensile loading. The bridges between the bricks controlled the strength of the specimen, and the crack tortuosity between the oblique edges of the polygonal bricks and the ductile polymeric adhesive enhanced its toughness. The improved strength and toughness of the MDF should inspire other studies to broaden the application of biomimetic composites to extreme environments requiring strong and tough materials.