| Abstract: | The room-temperature aging of two nitrile rubber–epoxy adhesives has been examined. Both are 121°C curing systems, based on DGEBA-type epoxy resins, one of which has been available for about 15 years while the other is a more recent development. It has been found that hydrolysis of the epoxide and polymerization both occur slowly, reducing the epoxide content and solubility. A major reduction in honeycomb peel strength of joints made with aged material was evident in the older system and to a lesser extent in the newer adhesive. This is a result of diminished adhesive flow. Tensile strength was less affected by aging. |
