Adhesive, also known asglue,cement,mucilage, orpaste,is any non-metallic substance applied to one or both surfaces of two separate items thatbindsthem together and resists their separation.
The use of adhesives offers certain advantages over other binding techniques such assewing,mechanical fastenings, orwelding. These include the ability to bind different materials together, the more efficient distribution of stress across a joint, the cost-effectiveness of an easily mechanized process, and greater flexibility in design. Disadvantages of adhesive use include decreased stability at high temperatures, relative weakness in bonding large objects with a small bonding surface area, and greater difficulty in separating objects during testing.Adhesives are typically organized by the method of adhesion followed byreactiveornon-reactive, a term which refers to whether the adhesivechemically reactsin order to harden. Alternatively, they can be organized either by their startingphysical phaseor whether their raw stock is of natural or synthetic origin.