The effect of air dried conditions on mechanical and physical properties of laminated and impregnated wood
AbstractIn this study, laminated Scotch pine samples bonded with polyurethane adhesive were impregnated with water repellent (protim WR230) and preservative (tanalith-C). Non-impregnated and impregnated
Scotch pine samples were air-dried by placing them uncovered in a concrete above ground for one year. Bending strength, compression strength, bonding strength and physical properties were determined.
Bending strength was reduced by 20% for non-impregnated samples, 12% for tanalith impregnated samples, and 11.3% for protimWR230. Compression strength was increased by 5.5% for nonimpregnated
samples, 10.1% for tanalith treated and 10.4% for ProtimWR230. Bonding strength was reduced by 8.3% for untreated samples, but increased by 36.05 and 35.7% for tanalith and ProtimWR230,
respectively. Impregnated samples were colonized by fungi during the one year outdoor conditioning; both dimensional and insect damages were not observed. Treated samples were well protected but nonimpregnated samples were covered by white rot, insects, color changes and considerable odour. In impregnating test samples, water and relative humidity affected the bonding properties positively for
one year, and this increased the bonding and compression strength. But bending strengths were reduced. In determining the bonding and compression strengths, the applied force parallel to adhesive
layer; while in determining bending strength the applied force is vertical to adhesive layer.