The primary current objective is to develop knowledge-based technologies of carbon nanotubes, understanding the surface chemistry and processing tools used in designing polymer-based composites. The chapter emphasizes the different functionalization processes and the parameters affecting the nanotube dispersability in polymeric matrices. We also describe different processing methods for incorporating such functional nanofillers into the polymer backbone. How functionalized carbon nanotubes can improve the thermal, mechanical and electrical properties of common epoxy matrices already used in advanced applications is also reported. Moreover, the chapter reviews the different chemorheological approaches adopted to describe the catalytic effects of pristine and functionalized CNTs on the curing of epoxy systems through the development and application of coupled kinetic and rheological models. Finally, the effects of functionalized CNTs on the thermal, electric and mechanical properties are reviewed and explained in terms of the interactions between the functionalized CNTs and typical epoxy resins used in advanced applications.