Ultrastructural characteristics of failure surfaces in medium density fiberboard

Abstract

The scanning electron microscope was used to examine the failure surfaces of medium density fiberboard panels fractured during internal bond (IB) and bending strength tests. During the IB test, panel failure occurred predominantly in the vicinity of the resin bridges and involved fiber intrawall failure usually at the S1/S2 interface within the cell walls. In the bending strength test, failure was both transwall and intrawall. Intrawall failure, similar to that found in IB test failures, occurred on surfaces parallel to the dominant fiber plane, while transwall failure of entire fibers was common on the edges of the breaks that were at right angles to the dominant fiber plane.