<p>Embodiments of the present disclosure include a thermoset cross-linked network and a method of producing the thermoset cross-linked network from a reaction product of a curable epoxy system in a liquid phase and cross-linked reactive polymer microparticles in a solid phase. For the various embodiments, the cross-linked reactive polymer microparticles have a cross-link density and reactive groups that covalently react with the curable epoxy system to provide the thermoset cross-linked network in a single contiguous phase having a topological heterogeneity.</p>