TABLE OF CONTENTS A vast variety of adhesives are commercially available either as a liquid or thixotropic paste and can be purchased over the counter from high street shops or through specialist distributors and manufacturers [1-3]. The vast majority of adhesives consist of a resin base and a curing agent (hardener) which when mixed in various proportions produce a hard matrix capable of provide an excellent bond between substrates such as metal, wood and ceramics [1]. Epoxy resins are utilised in the formulation of adhesives due to their exceptional mechanical properties whilst polyurethanes (PU) are favoured due to their flexibility. Many adhesives are designed to cure either at ambient temperature or require a heat source to promote crosslinking of the pre-polymers contained within, and hence curing. In certain circumstances single components are used where the resin component such as an epoxy pre-polymer and curing agent are combined together and curing is activated when a certain temperature is achieved. Typical curing agents used for these types of adhesives include boron trifluoride salts (BF 3) and dicyandiamides, the reactions of which are initiated at high temperature [1, 2]. A cured matrix may also be achieved by the interaction of the pre-polymer and moisture. This type of reaction occurs for PU. Nowadays there is practically an adhesive capable of bonding any two materials together whether it be concrete to metal, metal to metal, glass, carbon fibres, the list is endless [4].
Structural stability, negligible shrinkage as well as superior bond adhesion are important...
