The effect of alkyd coatings on the color changes and adhesion strength in parallel and perpendicular to fibers of date palm trees

In this study, the effect of alkyd coatings on the color changes and adhesion strength in parallel and perpendicular to fibers of date palm trees was investigated. For this purpose, the boards with the dimensions of 2 × 7 × 15 mm (parallel) and 5 × 5 × 5 (perpendicular) were prepared. Then, acid catalyzed and nitrocellulose lacquers (SC) and polyester (SP) coatings were applied and all specimens were then transferred to conditioning room (20±1 ºC, and 65 ± 1 % RH) for 15 days. Also, the quality coatings was evaluated by colorimetric and adhesion strength with pull-off test in parallel and perpendicular to fibers. The results of colorimetric showed that, after coating with acid catalyzed and nitrocellulose lacquers the . Also, coating in parallel direction caused a greater change in color than the perpendicular direction. Also, by parameter color saturation and hue of coating compared to the control sample increased and decreased, indicating that the transparency and gloss increases and the color tends to red-show have given. The results pull-off test showed that, the adhesion resistance of acid catalyzed and nitrocellulose lacquers (SC) was less than the polyester (SP) coating and the adhesion resistance in the perpendicular to fibers was generally 2 times higher than the parallel to fibers. Increasing adhesion resistance in cross section than the longitudinal section is due to better penetration of the coating into the fibers of palm, but in the longitudinal section it is due to the separation of the palm tissue.