Photo-Aging of High Performance Epoxies: Spectroscopic, Mechanical and Dynamic-mechanical Investigations

The photo-oxidative degradation of a densely cross-linked epoxide/diamine network based on tetraglycidyl-4,4 ' diaminodiphenylmethane (TGDDM) and 4,4 ' diaminodiphenyl sulphone (DDS) has been investigated by FTIR spectroscopy, dynamic-mechanical thermal analysis (DMTA) and compressive mechanical tests. The FTIR measurements allowed us to monitor the degradation process of the several groups present in the TGDDM/DDS network and to obtain reliable kinetic data. On this basis the most likely photo-degradation mechanisms were proposed, and the main pathways through which the degradation reaction proceeds were identified. Dynamic-mechanical measurements and mechanical tests were used to gain an insight in the effect of the photo-oxidative degradation on the relaxation processes of the epoxy network and on the mechanical performances.