Influence of the gaseous environment on the thermal degradation of a structural epoxy adhesive

A structural epoxy-based adhesive cured with dicyandiamide (DDA) and 4,4' d iaminodiphenylsulphone (DDS) has been aged at elevated temperatures under v arious gaseous environments. Weight loss was accompanied by enrichment of o xygen, sulfur, and nitrogen, near the polymeric surface, after aging in oxy gen containing atmospheres, as shown by X-ray analysis. Sulfur dioxide was detected in the aging environment. Results strongly suggest chain scission by thermolysis combined with thermo-oxidative degradation occurring near th e exposed surface. (C) 2000 John Wiley & Sons, Inc.