4.5.1 Effect of the Environment

As the environment to which an adhesive bond is exposed can degrade the adhesive’s polymeric structure, influencing the cohesive bonds or undermining the bond with the surface, it is necessary to evaluate the environmental conditions and the mechanical forces to which the joint will be exposed.

Adhesives may see varied outdoor climates, such as semi-arid, tropical and coastal climates. Specific standards are designed for gauging the effect of these conditions, real-time or simulated, on bonded assemblies. Aside from external environments, the application can impose severe conditions. Extremes in major appliances like ovens, freezers and dishwashers, and in automotive engines, aerospace and medical device sterilisation should all be anticipated and tested before an adhesive bond is green-lighted for production. It is important to test both environmental and physical stresses concurrently, as the additive effect may be more severe than each individually. The good news is that adhesives are so versatile that there are choices for almost every situation. Adhesive manufacturers and distributors can provide expert advice on applying adhesives in extreme environments.