Studies on the Curing Characteristics of Wood Adhesives and theDevelopment of New Bio-based Wood Adhesives

Abstract

In this comprehensive paper, researches on the curing and adhesion properties of wood adhesives andthe development of bio-based adhesives which author have been experimented were introduced. The curingand adhesion properties of adhesives under steam-injection heating were different from those of hot-platenheating, and the effective method for obtaining good bonding properties under steam-injection heating wasrevealed. The dynamic mechanical properties of water-cured pMDI were observed because reaction withwater is main curing reaction when using pMDI as a wood adhesive. The effect of a small amount additionof polyol on physical and adhesion properties of water-cured pMDI were clarified. The evaluation of theadhesion durability of pMDI using steam-injection heating was introduced, and it was shown that moisture hadgreat influence on adhesion durability. As a development of new bio-based adhesives without depending onfossil resources, utilization of chitosan and citric acid was indicated. Chitosan had good dry and wet bondingproperties, and the adhesion properties of chitosan were improved by utilization of the Maillard reaction. Thecitric acid brought chemical adhesion with wood component, and the bonding properties of citric acid wereimproved by addition of sucrose.