PHOTOCHEMICAL DEGRADATION STUDY OF AN EPOXY MATERIAL BY X-RAY-ANALYSIS

Photo-chemical degradation of an epoxy resin (DGEBA) cross-linked with methyltetrahydrophthalic anhydride (MTHPA) was studied using electron beam X-ray microanalysis. The evolution of O-K alpha/C-K alpha ratio of the K alpha ray intensities of oxygen and carbon allowed us to dete ct the organic matrix's chemical modifications during photo-ageing of the irradiated surface. Aside from the fact that the thickness of the photo-oxidized layer can be estimated, the evolution of the O-K alpha/ C-K alpha ratio is expressed as that of the oxidation of the matrix a nd confirms the hypothesis that the photo-oxidation layer advances at a constant rate, after an establishment period. (C) 1998 Elsevier Scie nce Limited. All rights reserved.