Epoxy reactive liquid modifiers include acrylate functionalized compounds, acrylamide functionalized compounds, oxalic amide functionalized compounds, actoacetoxy functionalized urethanes and acetoacetoxy functionalized polyalkenes. The reactive liquid modifiers are incorporated into epoxy resin compositions comprising a curable epoxy resin, an amine curing agent, and the reactive liquid modifier, wherein the reactive liquid modifier is polymerized to form at least one of an interpenetrating polymer network and a semi-interpenetrating polymer network with the curable epoxy resin.