Published Online: 14 August 2008
Page Count: 17
Wolf, Andreas T.
Ph.D., Scientist, Dow Corning GmbH, Wiesbaden, Hessia
(Received 26 February 2008; accepted 8 July 2008)
Moisture in the form of humidity, condensation, rain, or water immersion is the most commonly encountered element of the service environment and must be considered a critical factor in determining the long-term reliability of sealed or bonded joints. Moreover, the effects of moisture are exacerbated by elevated temperature. For many polymeric systems, warm, moist environments can considerably weaken the bulk or interfacial performance properties of the jointing materials formulated with these polymers. The majority of joint failures in service environments that comprise water exposure occur by degradation of the interface(s) between sealant or adhesive, primer, and substrate. Therefore, predicting the interfacial degradation in an actual service environment is of utmost importance. This paper provides information on the current understanding of the role of water in the failures of adhesive and sealant joints and discusses the usefulness of the Arrhenius’ relation in predicting the lifetime of sealed or bonded joints based on data generated at elevated temperatures. Finally, the paper suggests some guidelines aimed at improving the reliability of accelerated test and prediction procedures used in the evaluation of the durability performance of sealed or adhered joints in immersed environments.
Paper ID: JAI101721