POSS-functionalized polyphosphazene nanotube: preparation and effective reinforcement on UV-curable epoxy acrylate nanocomposite coatings

This study presents an efficient method of preparing functionalized poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) nanotube reinforced UV-curable materials. Octamercaptopropyl polyhedral oligomeric silsesquioxane (OMP-POSS) functionalized PZS (POPZS) nanotubes, prepared via a thiol–ene click approach, were covalently incorporated into epoxy acrylate (EA) by UV irradiation technology. The results of transmission electron microscopy and X-ray photoelectron spectroscopy indicated that OMP-POSS was successfully grafted onto the surface of PZS nanotubes. Dynamic mechanical analysis was employed to investigate the dynamic mechanical property of POPZS/EA nanocomposite coatings. The optimal reinforcing effect for EA matrix was observed at the 3.0 wt% loading of POPZS nanotubes. The storage modulus at 30 °C and glass transition temperature was dramatically improved by 88% and 16 °C, respectively, compared to those of pure EA. Moreover, the char yield at 800 °C of the nanocomposites was significantly increased, indicating the remarkably improved thermal stability. These extraordinary reinforcements of properties are attributed to effective reformative interfacial interaction between POPZS nanotubes and EA matrix by covalent linkage.