A novel custom-tailored epoxy prepreg formulation based on epoxy-amine dual-curable systems

Dual-curable formulation was used to prepare epoxy prepregs with tailored tack and drape. The obtained formulation had enhanced stability during the storage which eliminates the instability as the main drawback of prepregs. Diethylenetriamine was used as a low-temperature curing agent in the off-stoichiometry ratio for precuring and dicyandiamide was used as a latent curing agent for final curing. DSC Tests showed that simultaneous presence of two curing agents with different reactivities results in two different curing reaction without interference. FT-IR and DSC tests showed that the inactivity of latent curing agent in the pre-curing step causes to the loss of thermal history. The FT-IR tests showed only a 7% increase in conversion after 21 days of storage at room temperature. Tack and drape as main parameters of epoxy prepreg were tailored by adjusting the degree of cure based on using different amount of double curing agents.