Study on water resistance improvement of wood dowel rotation welding joints

Rotation welding of wood dowels has the advantages of high bonding strength, fast processing speed and green environmental protection, and is suitable for jointing nodes in furniture and wood products. However, most wood friction welding specimens have poor water resistance where the welded joints are more likely to be damaged in wet environments, which greatly limits their wider application. Previous studies focused on using natural and green materials or methods to enhance bonding strength and water resistance of friction-welded joints. This paper reveals an innovative chemical pretreatment method to improve the water resistance of rotary friction welded joints by treating the substrate blocks or dowels with reagents that successively oxidize and sulfonate the wood, and spraying the dowels with Zinc acetate alcohol solution that has a lubricant effect, followed by friction welding. The findings show that both the dry bonding strength of friction welded joints and the wet bonding strength after impregnation with cold, hot, and boiling water of dowels pretreated with oxidation and sulfonation reactions were higher than those without pretreatment and significantly superior to the traditional polyvinyl acetate (PVAc) adhesive bonding.