Forestry 485 Lecture 2-1: Introduction to Adhesion
Adhesion • Adhesion – from the Latin adhaere, “to stick to” • In a practical sense, adhesion is the mechanism by which an adhesive transfers a load from an adherend to the adhesive joint -Packham, 1992
Adherends=solid materials in the adhesive joint, other than the adhesive • Adhesive=(generally) polymeric materials that exhibit viscoelastic properties; capable of bonding to adherends and transferring load from the adherend to the adhesive joint • Adhesive joint=an assembly made by the use of an adhesive. Also called an adhesive bond. -Pocius, 2002
“Adhesive bonding is a method by which materials can be joined to generate assemblies. Adhesive bonding is an alternative to more traditional mechanical methods of joining materials, such as nails, rivets, screws, etc.” -Pocius, 2002
Two primary functions of an adhesive: • 1. Adequately bond to the surface of adherends • 2. Contribute appropriate mechanical properties upon curing (load transfer)
Advantages and Disadvantages of Adhesive Bonding • Advantages: • Minimize stress concentrations • Viscoelastic behavior of adhesive contributes to absorption of applied mechanical load • Dissimilar materials can be joined
Advantages and Disadvantages of Adhesive Bonding • Disadvantages: • Complex behavior at the surface of adherends; complex behavior of adhesive resin formulations • Adhesion occurs within a composite material; difficult to establish if proper bonding occurs
References • Packham, D. 1992. Adhesion, p. 18-20 in Handbook of Adhesion. John Wiley and Sons, New York. 570 pages. • Pocius, A. 2002. Chapter 1, p. 1-14 in Adhesion and Adhesives Technology: An Introduction. Hanser Gardner Publications Inc. Cincinnati, OH. 319 pages.