Thermal degradation of tetrafunctional/phenol novalac epoxy mixture cured with a diamime

The effect of thermal degradation on the mechanical behaviour of a system c ontaining both tetraglycidyl-4-4'-diaminodiphenylmethane (TGDDM) and a mult ifunctional novolac glycidyl ether (EPN) resins, cured with 4,4'-diaminodip henylsulphone (DDS) has been studied using dynamic mechanical analysis (DMA ) and tensile tests. Different curing paths using the isothermal time-tempe rature-transformation (TTT) diagram for this system were designed, obtainin g thermosetting materials with different conversions; The influences of the degree of cure and of the aging temperature were also studied. The results showed different trends in the dynamic mechanical properties and an increa se in the stiffness of the material with increasing aging time. Changes wer e faster and more intense with the higher temperature.