Impact of bark content on the properties of medium density fiberboard (MDF) in four species grown in eastern Canada
2006
Xing, C. | Deng, J. | Zhang, S.Y. | Riedl, B. | Cloutier, A.
Medium density fiberboard (MDF) is generally produced from bark-free raw materials. The maximum bark content of MDF products is about 1 percent by weight. The potential of using large amounts of bark as raw material for MDF and the effects of bark content on panel properties are still unclear. The characteristics of wood fibers and bark fibers of four species grown in eastern Canada (hybrid poplar, jack pine, red pine, and white spruce), as well as the influence of bark-derived fiber content on the performance of MDF were investigated. There was no obvious change in pH between bark and bark-derived fiber, but the pH of wood-derived fiber was obviously lower than that of wood. The bulk density of refined bark fibers was higher than that of wood fibers for the same species at the same refining conditions. The effect of including bark on all mechanical properties including modulus of rupture (MOR), modulus of elasticity, internal bond, and linear expansion is more detrimental than that of thickness swelling and water absorption. However, all the properties of bark-included MDF panels, made from up to 40 percent bark fibers met the ANSI standard (except for TS and for one case of MOR).
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