Influence of Strand Size, Board Density, and Adhesive Type on Characteristics of Oriented Strand Lumber Boards Manufactured from Pine Strands

Abstract

The influence of selected technological aspects was studied relative to characteristics of oriented strand lumber (OSL) boards manufactured from pine strands. Six types of boards were prepared, differing in the strand fraction size, density (700 kg/m3 and 800 kg/m3), and adhesive used to glue the strands in the core layer. The adhesives compared were melamine-urea-formaldehyde (MUF) and polymeric diphenylmethane diisocyanate (pMDI). The results showed that the OSL boards had good physical and mechanical properties, even though pine strands of diverse characteristics, particularly in terms of their length and width, were used for their production. The influence of strand size was clear in the results of the bending and elongation tests. Both for the bending test and tensile strength in a direction parallel to the wood grain, the properties were on average 20% greater for boards made of larger strands compared to those made of smaller strands. However, the latter demonstrated greater internal bonding strength (IB). The weakness of OSL boards made from small strands was their low modulus of elasticity, particularly when the board density was simultaneously reduced.