Experimental study on correlation between adhesive penetration pattern and mechanical performances in oriented strand board

摘要

The aim of the experimental study presented here is to investigate the correlation between adhesive penetration and mechanical performances of wood-based composites. For this purpose, oriented strand boards were made with poplar uni-strands and PF resin. To make differences in resin penetration, strand moisture content (MC) and resin solid content (SC) were selected as variables of the experiment. The adhesive penetration pattern was studied by the elemental counting method (ECM) in two layers of the boards' thickness. Mechanical properties including MOE, MOR, IB, tensile strength parallel to the grain, impact resistance, and creep bending were evaluated as well as resin droplets distribution. The results showed that strand MC and resin SC influence the mechanical performance and resin penetration parameters. The penetration parameters increased in the middle layer where the bondlines are close to heat and hydrodynamic pressure sources. The composites made with higher concentration resin and drier strands expressed weak penetration causing a reduction in mechanical properties except for tensile strength where the shear stress took place between bonded strands. Resin droplet size analysis proved that resin SC could change the droplet size distribution and influence the strengths. Strand MC could act as a modifying factor to develop the penetration and balance it between the layers. The results of the correlation analysis proved a significant relationship between mechanical properties and penetration parameters, in particular, those obtained from fiber quantity.