Radiation curing of selected structural adhesives

Radiation curing of structural adhesives offers a number of potentially significant advantages over thermal curing for ease of processing, performance and energy conservation. This capability to effect cures at ambient temperatures and in quite short periods of time by exposing an uncured adhesively bonded assembly to a suitable source of ionizing radiation is particularly attractive. Experiments have been carried out to identify polymer systems for adhesive applications which can be cured via radiation and to optimize their performance when exposed to various environmental conditions including high temperature service. Data have been developed on the lap shear strength properties of a number of candidate structural adhesive systems such as polyesters, vinyl esters, acrylics and modified polyimides. Aluminum test specimens which were cured with electron beam radiation over a wide range of dosages, were employed for these studies. Preliminary conclusions are presented on the performance of these systems and recommendations are made for optimizing this technique for curing prototype assemblies with industrial electron beam accelerator equipment.