Factors affecting the bond between polymer composites and wood

Bond strength and durability play a vital role in the effectiveness of wood strengthening with fiber-reinforced polymer composites. This paper analyzes the effects that resin system, wood surface condition, moisture content, primer application, and environmental exposures have on bond strength. FRP composites were made by hand-layup with two types of epoxies and E-glass fabric on seven different wood surfaces. Bond strength was measured as fabricated, and after the following environmental exposures - soaked under water, dried in high temperature and cyclic tidal salty water. Results show a relationship between resin type and wood moisture content with respect to bond strength. Application of the composite on a rough surface overall improves the bond strength. Application of hydroxyl methanol resorcinol (HMR) overall improves the bond strength except in a dry environmental exposure.