Natural Adhesives, Binders, and Matrices for Wood and Fiber Composites

Abstract

Recent developments and trends in the field of bio-based adhesives are reviewed. The more recent developments in tannin adhesives without the use of aldehyde-yielding compounds under the conditions of processing, or even without the use of hardeners, are described. Lignin adhesives are discussed next. The combination of these two types to yield natural environmentally friendly matrices for non-woven fiber mats is also reviewed. Several new trends in the developments of protein adhesives and in carbohydrate adhesives are then addressed. Unsaturated oil adhesives based on epoxidized unsaturated vegetable oils are also described as well as an example of cashew nut shell oil modified by a new and inexpensive method to yield an adhesive by self-condensation of the material. The chapter addresses last the new process of solid wood friction welding without the use of adhesive, in which the wood interface itself is used as the binder.