Chapter 17 - The durability of adhesive joints

Abstract

This chapter discusses the durability of adhesive joints and the aspects of environmental attack with a special reference to the effect of moisture, especially when elevated temperatures or applied stresses are also involved. The discussions in the chapter largely, though not exclusively, centre on those environments/adhesive systems where the interfacial regions are attacked. It also discusses the various mechanisms of attack which may explain the loss of durability. The chapter also illustrates the various methods that may be employed to extend the service-life. The important role of the interfacial regions, that is, the ''interphase'', of the bonded joint is evident, since most of these methods are based upon some form of pretreatment for the substrates prior to bonding. Secondly, the kinetic factors behind the mechanisms will be reviewed, and thirdly methods for ranking and predicting the service-life from short-term experiments are considered. The important role that continuum fracture mechanics may play in (a) identifying the mechanisms of environmental attack, (b) ranking the durability of different adhesives, and (c) quantitatively predicting the lifetime of bonded joints and components, are emphasized.