The effect of Kevlar fiber reinforcement on the curing, thermal, and dynamic-mechanical properties of an epoxy/anhydride system

Curing, thermal, and dynamic-mechanical relaxational behavior of an epoxy/a nhydride resin and a Kevlar-fiber/epoxy composite were compared. Reinforcem ent by Kevlar fibers had a catalytic effect on the curing reaction. Reinfor ced formulations produced higher extents of reaction than neat formulations at the same curing time. Curing kinetics was also studied by means of DSC heating scans. When the Kevlar content increased, the heat flow curves and the exothermic peak temperature shifted significantly to lower temperatures . The glass transition temperature of the matrix also decreased as the Kevl ar content increased. Postcuring reduced the differences between the neat a nd reinforced formulations. Loss tangent and storage modulus versus frequen cy master curves were obtained from isothermal dynamic-mechanical measureme nts. The effect of fiber addition on the main dynamic-mechanical relaxation was analyzed with a simple mechanical model.