Multi-functional vinyl monomers, which are highly reactive towards free radicals and are readily graft to polymer chains, ordinarily form a complex cross-linked network with the latter. Initial phase distribution within the polymer matrix is of a great importance for the final user properties of a composite material. Based on the mechanisms of cross-linking process' reactions, a new theoretical kinetic model framework was developed incorporating blend morphology. The kinetic model was then applied to the cross-linking process' reactions of various monomer moieties and a chosen complex polymer compound, namely partially hydrogenated poly(acrylonitrile-co-1,3-butadiene) alongside with an organic peroxide. Whereas the blend morphology was determined utilizing field emission scanning electron microscopy, the overall concentration of cross-links' evolution was monitored through viscoelastic characteristics of the system. The model demonstrated good agreement with experimentally measured data and, moreover; the evolution of concentrations of various crucial species inherent to the cross-linking process were predicted in homogeneous, heterogeneous, and interfacial phase. The most significant advantage of the developed kinetic model is that it may be readily applied to an assortment of polymer/monomer/peroxide systems. (C) 2010 Elsevier Ltd. All rights reserved.