epoxy prepreg obtained via two sequential epoxy-amine condensations

Despite the excellent properties, the instability of prepreg during the storage has reduced the efficiency and increased the waste of these materials# the idea of using a dual-curable formulation was investigated to eliminate this instability# in this idea, diethylenetriamine was used as a low-temperature curing agent in the off-stoichiometry ratio for pre-curing and dicyandiamide was used as a latent curing agent for final curing# the results of dsc showed that simultaneous presence of two curing agents with different reactivity resulted in two different curing reaction without interference# the results of ft-ir and dsc tests showed that the inactivation of latent curing agent in the pre-curing would cause thermal history loss#