The layer performance of water based varnishes on wood preprocessed with various chemicals

The aim of this study was to determine the physical and mechanical properties of water-based varnishes on wood surfaces preprocessed such as removing the grease and glue from the wood surface and lightening of color, and the performance after the UV aging tests.In the study, Scotch pine (Pinus sylvestris L.), European oak (Quercus petreae mill), and iroko (Chlorophora excelsa) woods were utilized. Firstly, prepared specimens were contaminated with grease and PVAc glue, then the grease was removed from the wood surface with soft soap, and glue was removed with acetone. Lightening of color process was applied with oxalic acid (H2O2C4) and hydrogen peroxide (H2O2). Afterwards, preprocessed specimens impregnated with immersiol aqua and wood protecting impregnation materials, and both materials. Then, protective layers were applied to the surfaces with water-based varnishes that are single component primary resin (PR), double component polyurethane modified with acrylic (APK), and double component elastic polyurethane (EP). After these processes, the specimens were exposed to the accelerated aging (HYİ) tests for 240 hours. Hardness, glossiness, color properties (?E) and surface bonding tests were applied in order to determine the performance of finishes. Hardness, glossiness, color, and bonding of the varnish layers were determined according to ASTM D 4366-95, ASTM D 523-89, ASTM D 2244, and ASTM D 4541 standards, respectively. The UV accelerated aging tests were made based on the principles of ASTM G 151 and ASTM G 154?06.Test results showed that preprocesses such as removing the grease and glue from the wood surface and lightening of color were increased the hardness of the layers. On the other hand, the hardness values increased after the accelerated aging process. Accelerated aging process was decreased the glossiness of PR layers on scotch pine while it was increased the ?E. The maximum color increment was obtained with scotch pine specimens. Impregnation and preprocesses were decreased the bonding of the varnish layers, while the UV rays had a positive influence in accelerated aging. The maximum increment was obtained with EP layers on scotch pine specimens.