Delamination resistant composites prepared by small diameter fiber reinforcement at ply interfaces

A prepreg comprising a resin matrix and primary reinforcement fiber, said prepreg further comprising a secondary fiber layer apart from said primary reinforcement fiber at one or both surfaces of the prepreg, or one or more portions of said one or both surfaces of the prepreg, said secondary reinforcement fiber layer comprising fibers having a diameter smaller than said primary fiber, said secondary fiber layer including fibers having a diameter less than 4000 nanometers and at least 3 nanometers.

A method of making a resin prepreg, said method comprising the steps of providing an initial prepreg reinforced with primary reinforcement fiber, and applying secondary reinforcement fiber to one or more portions of at least one surface of said initial prepreg, wherein said secondary reinforcement fiber is smaller in diameter than said primary reinforcement fiber, said secondary reinforcement fiber having a diameter less than 4000 nanometers and at least 3 nanometers.

A laminate comprising a plurality of stacked layers, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one or more portions of said at least one interface, wherein said secondary fibers are smaller in diameter than said primary reinforcing fibers, and wherein said secondary fibers are applied in the form of a random mat.

A laminate comprising a plurality of stacked layers, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one or more portions of said at least one interface, wherein the ratio of primary reinforcement fiber diameter to secondary reinforcement fiber diameter is about 10:1 or greater.

A laminate comprising a plurality of stacked layers, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one or more portions of said at least one interface, wherein said secondary fibers are smaller in diameter that said primary reinforcing fibers, said secondary fibers having a diameter less than 4000 nanometers and at least 3 nanometers, and wherein the primary reinforcing fibers a preimpregnated with matrix material prior to forming the laminate.

A laminate comprising a plurality of stacked layers, each of said stacked layers having a thickness, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers embedded in said matrix material, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one of more portions of said at least one interface, wherein the presence of said secondary reinforcing fibers in said at least one interface forms a reinforced interlayer between said stacked layers, wherein said secondary fibers are smaller in diameter than said primary reinforcing fibers, said secondary fibers having a diameter less than 4000 nanometers and at least 3 nanometers, and wherein the thickness of said reinforced interlayer is about 12% or less of the thickness of said adjacent layers.

A laminate comprising a plurality of stacked layers, each of said stacked layers having a thickness, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers embedded in said matrix material, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one or more portions of said at least one interface, wherein said secondary reinforcing fibers are smaller in diameter than said primary reinforcing fibers, said secondary reinforcing fibers having a diameter less than 4000 nanometers and at least 3 nanometers, and wherein said laminate is manufactured without preimpregnation of the secondary reinforcing fibers with matrix material.

A laminate comprising a plurality of stacked layers, each of said stacked layers having a thickness, said layers forming an interface between each pair of adjacent layers, said layers comprising a matrix material and primary reinforcing fibers embedded in said matrix material, and said laminate further comprising secondary reinforcing fibers present in at least one interface, or one or more portions of said at least one interface, wherein the presence of said secondary reinforcing fibers in said at least one interface forms a reinforced interlayer between said stacked layers, wherein said secondary reinforcing fibers are smaller in diameter than said primary reinforcing fibers, said secondary reinforcing fibers having a diameter less than 4000 nanometers and at least 3 nanometers, and wherein said secondary reinforcing fibers comprise continuous fibers.

A method of making a resin prepreg, said method comprising the steps of preimpregnating primary reinforcement fiber with uncured or partially cured resin to produce preimpregnated primary reinforcement fiber, and applying secondary reinforcement fiber to one or more portions of at least one surface of said preimpregnated primary reinforcement fiber, wherein said secondary fiber is smaller in diameter than said primary reinforcement fiber, said secondary fiber having a diameter less than 4000 nanometers and at least 3 nanometers.