Adhesives can offer substantial economic advantages over more conventional methods of joining. Whilst the building and construction industries represent some of the largest users of adhesive materials, few applications currently involve adhesive joints which are required to sustain large externally-applied forces. However, recent advances in the science and technology of adhesion and adhesives suggest that structural adhesives have enormous potential in future construction applications, particularly where the combination of thick bondlines, ambient temperature curing and the need to unite dissimilar materials with a relatively high strength joint are important. Indeed adhesive bonding, either alone or in combination with other methods of fastening, represents one of the key enabling technologies for the exploitation of new materials and for the development of novel design concepts and structural configurations.

Definitions and bonding

An adhesive may be defined as a material which, when applied to surfaces, can join them together and resist their separation. Thus adhesive is the general term used for substances capable of holding materials together by surface attachment and includes cement, glue, paste, etc. There is no universally accepted definition of a structural adhesive, but in the following chapters the term will be used to describe monomer compositions which polymerise to give fairly stiff and strong adhesives uniting relatively rigid adherends to form a load-bearing joint.

The term adhesion refers to the attraction between substances whereby when they are brought into contact work must be done in order to separate them.