Effect of heat treatment on adhesion strength of clear coatings in beech and poplar wood

he aim of this study was to investigate the influence of heat treatment of wood on adhesion strength of clear coatings. For this purpose, specimens of beech and poplar wood with dimensions of 20×100×150 mm3 prepared. Heat treatments were performed in 160 and 180 °C for 3 hours in dry condition. Surface of treated and untreated specimens were covered with clear coatings in three separate processes: 1. sealer-acid catalyzed lacquer, 2.polyurethane and 3. Special coating of thermowood. After applying the coating, the adhesion strength (Pull-off) and scratch (Cross-Cut) were measured and compared to untreated specimens. Results showed that by increasing the temperature of heat treatment, adhesion strength reduced. The reduction in polyurethane coating and sealer-acid catalyzed lacquer was statistically significant. The adhesion strength of coating in the Beech wood was higher than poplar wood. The best adhesion strength observed in polyurethane coating and the lowest quantity was obtained in sealer-acid catalyzed coating.