Adhesives for elevated-temperature applications

Although adhesives, particularly those based on epoxy resins, are finding increasing use in structural applications, their utilization at elevated temperature (>150degreesC) has been limited by their relatively poor thermal and thermo-oxidative stability. As a result, significant effort has been directed in recent years toward the development of polymers exhibiting increased thermal resistance. Although a wealth of research conducted over several decades has resulted in a myriad of polymer types exhibiting, in some cases, impressive high-temperature performance, many systems have demonstrated poor processability. Thus, much emphasis has been placed on developing high-temperature performance while providing processability characteristics that are similar, if not identical, to epoxies. This article considers the various approaches that have bben shown to offer such dual capabilities. In addition, the results of various studies undertaken to investigate the effects of elevated temperature on the strength and fatigue resistance of bonded joints are reported.