The Effect of Linseed and Tung Oils on the Friction Coefficient of Wood in Weathered Conditions

Slippery wooden surfaces in outdoor recreational settings present a serious safety risk for users of these areas. Slippery surfaces can become increasingly concerning when these surfaces are exposed to moist conditions. This study analyzed whether natural oil treatments such as linseed oil and tung oil were effective in improving the static friction coefficient of the surface of yellow pine wood after environmental weathering. It was hypothesised that linseed or tung oil would increase the friction coefficient of the wood due to their hydrophobic properties and their ability to resist the growth of fungi. To assess the hypothesis, 3 types of wood treatment (untreated, tung oil, and linseed oil treated) were applied to planks of yellow pine wood and then exposed to moist soil for one week with the intent of introducing moisture and fungi to the surfaces of the wood. After this period, a hinged incline apparatus was constructed to determine the critical angle at which a weighted shoe and bicycle tire each began to slide down the treated wood surface. After these angles were determined, the static friction coefficient between the given surfaces was calculated using mechanics-based formulas. The results showed that tung oil was the strongest overall wood treatment with significant increases present in both the shoe and bicycle tire tests while linseed oil only had minimal effects on the bicycle tire. A two-way ANOVA test demonstrated a p-value of less than 0.001 deeming the results statistically significant meaning that a noticeable difference was found between the trials with different treatments. The mean of tung oil illustrated an increase of around 5% and linseed oil about 0.1% when compared to the untreated wood plank. The untreated board had the greatest range and standard deviation with tung oil and linseed oil following in a decreasing pattern.