Linear expansion and surface stability of particleboard

Particleboards were manufactured under laboratory conditions from furnishes derived from two species (aspen and red pine) and subdivided into various screen fractions. The finished boards were evaluated in terms of their linear expansion (LE), surface quality, and surface stability. The LE of pine boards reflected the abnormally high longitudinal expansion of solid pine wood from the interior portion of the log (juvenile wood). Aspen boards showed no such effects. Surface quality and stability were measured on board samples overlaid with melamine-impregnated paper. Furnish compaction was the major variable; higher compaction produced better surfaces. However, high compaction also caused greater surface deterioration with changes in moisture content.