| abstract |
A curable prepreg ply formed by applying two outer resin films to the top and bottom surfaces, respectively, of a layer of resin-impregnated reinforcement fibers. The outer resin films contains insoluble toughening particles, and partially soluble or swellable toughening particles, but the resin matrix which impregnates the reinforcement fibers does not contain the same toughening particles. The insoluble toughening particles are insoluble in the resin matrix of the resin films upon curing of the prepreg ply. The partially soluble or swellabbe toughening particles are partially soluble or swellable in the resin matrix of the resin films upon curing of the prepreg ply, but remain as discreet particles after curing. |