Combined physical modification of polymer adhesives used in woodworking

Abstract

Abstract There is a shortage of valuable wood species in the world. One of the easiest and affordable ways to replace is to create glued products from scarce wood species by gluing oversized blanks. Products made of glued blanks are not inferior to the products made of solid wood in quality and properties. These products have the properties of rare wood species. However, growing demand on the quality of glued products constantly challenge technologists to increase the strength of adhesive joints. This problem can be solved in several ways: development of new bonding technologies, creation of special adhesives for a specific task and modification of known adhesives. The aim of the research is to increase the adhesive strength of wood due to decrease of adhesive viscosity and decrease in wetting angle. It is achieved due to directional effects of combined physical field to resin. Urea-formaldehyde resin and oak wood specimens have been considered as the object of the research. As a result of the resin modification, strength of the adhesive joint along the fibers increased by 2 times (196%), while the values of the viscosity and wetting edge angle were reduced by 62% and 82%, respectively.