The Internal Bond and Shear Strength of Hardwood Veneered Particleboard Composites

The effects of several accelerated aging tests and weather exposures on hardwood reconstituted structural composite panels were evaluated. The results indicated that the internal bond and shear by tension loading strength reductions of the panels were affected by the exposure test method. The ranking of the effects of various exposure tests on strength values in an increasing order of severity was (1) 24-hour soak, (2) 1-hour boil, (3) 2-hour boil, (4) ASTM-6 cycles, and (5) WCAA-6 cycles. Both ASTM and WCAA tests had similar influences on IB and shear strength properties. Also, 4 cycles of either of these tests resulted in about the same degree of strength reduction as 6 cycles. In addition to test methods, a few construction variables were evaluated. The type of glueline, dry phenolic resin film and wet melamine-urea formaldehyde resin used to laminate the veneer over the core material yielded similar strength values. Other construction variables evaluated indicated that panels with an exterior particleboard core made from smaller particles as compared to wafers had higher IB values than waferboard core panels.