Effects of heating treatment on some of the physical properties of varnish layers applied on various wood species
The aim of the current study is to determine the effects of different heat treatment and varnish combination applications on some of the physical properties of wood materials sampled from limba (Terminalia superba), iroko (Chlorophora excelsa), ash (Fraxinus excelsior L.) and Anatolian chestnut (Castenea sativa Mill.) species. The heat treatment was applied at two levels (150 and 180°C) for both 3 and 6 h period. Once heat treatment was conducted, four types of varnish layers (cellulose lacquer, synthetic varnish, polyurethane varnish and water based varnish) were applied to the materials. After the treatments application, color, brightness and surface roughness of varnish film layers of the treated woods were measured. The effects of heat treatment and varnish combination applications on the earlier mentioned variables were analyzed according to the study design (factorial design with 4 (species) x 2 (heat) x 2 (duration) x 4 (varnish) = 64 experimental units). For significant analysis of variance (ANOVA) , Duncan mean separation test was performed to separate the interaction combinations. Results of the study indicated that surface roughness increased on wood samples for all four wood species treated with cellulose lacquer and synthetic varnish and across all heating treatments. However, surface roughness decreased for all wood species depending on heating temperature and time. As such, the value of brightness also decreased for all four wood species across all the treatment combinations. The results obtained from the upper surface of the enforcement process are thought to contribute to the national economy.
Key words: Heating treatment, cellulose lacquer varnish, synthetic varnish, polyurethane varnish, water based varnish, surface roughness, brightness, color changes.