Effect of wood moisture content on adhesion of varnish coatings

In this research, experimental samples were prepared using Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.) and oak (Quercus petraea L.) with moisture content of 8, 12 and 15% and were coated with cellulosic (nitrocellulose), two-part polyurethane (urethanealkyd), and waterborne (self-crosslinked polyurethane) varnishes in order to determine the effect of wood moisture content on adhesion. According to research results, it was found that the difference in moisture content had substantial effect on the adhesion of varnishes, applied on the wood surfaces. The highest adhesion was obtained from two-part polyurethane varnish, applied on oak specimens with a moisture content of 8%.