To further support how the distribution of MEPECO affects the mechanical properties of the VE, morphological analysis using an optical microscope (OM) and a scanning electron microscope (SEM) was observed. Figure (e) shows OM images, which provide valuable insights into the distribution and dispersion of MEPECO on the surface of VE resin. The dispersion of a much wider whitish surface upon the gradual increase of MEPECO shows the aggregation and phase separation within the VE resin. It might also suggest that a change in optical properties or refractive index confirms the presence of MEPECO in VE resin. The gradual increase in the area occupied by the white surfaces may indicate that maleated epoxy resin is not homogeneously distributed within the vinyl ester resin. Instead, it may be forming localized clusters or domains. Thus, the degree of dispersion or aggregation can be indicative of the compatibility of the maleated-epoxy resin or epoxidized corn oil with the vinyl ester resin.