Physical properties of strawboard as affected by processing parameters

Wheat straw has been recently considered as an alternative to wood fibers in manufacturing particle boards. The objective of this study was to investigate the effects of processing parameters on straw particle board quality. Commercial ground wheat straw was used in a full factorial experimental design to examine the effects of three processing variables (initial straw moisture content (MC), resin binder content (BC), and press temperature) on strawboard physical and mechanical properties. The MC was tested between 2 and 12%, BC between 2 and 8%, and press temperature between 135 and 218 degrees C. Strawboard density was held constant by controlling the gap in the press mold. Dimensional stability and water resistance was determined by a 24-h water-soak test, and mechanical properties by a three-point flexural test. In the tested parameter range, BC was the most significant factor affecting the strawboard dimensional stability, water resistance and mechanical properties. Initial straw MC was the second most significant factor influencing strawboard quality. MC had a more significant effect on board mechanical properties than on dimensional stability. Press temperature had a more significant effect on the strawboard dimensional stability than on mechanical properties. (C) 2000 Elsevier Science B.V. All rights reserved.