- Phillips, Daniel
The Graduate School University of Maine
In this research, acoustic emission technology was used to measure the moisture excluding effectiveness (MEE) of coatings on wood. Moisture interaction with wood causes damage, and coatings such as paints and varnishes can effectively limit this interaction. Over time, the moisture excluding effectiveness of wood is reduced by the actions of weathering, and the resulting wood-water interaction leads to problems due to the dimensional instability of the wood.
Five coating types, at two spreading levels, were tested on three species of wood for MEE using acoustic emissions monitoring equipment. The samples were exposed to three weathering conditions to simulate the effects of exposure. Cumulative counts and energy, as well as changes in size and weight, were measured during exposure to water.
The results show that acoustic emission technology is an effective method for measuring the moisture excluding effectiveness and weathering degrade of coatings on wood. Of five coatings tested, the most effective was found to be an oil-based paint, and the worst performance was by a water-based clear poly-urethane. A species effect was also evident.