A comparative study of TiO 2 and surface‐treated TiO 2 nanoparticles on thermal and mechanical properties of poly(ε‐caprolactone) nanocomposites

Polymer/inorganic nanocomposites were significant hybrid materials because of their unique properties. The surface of bare nanoparticles (b‐TiO 2 ) was modified by aminopropyl trimethoxy silane to obtain grafted TiO 2 (g‐TiO 2 ) nanoparticles for the improvement of nanoparticles dispersion. The b‐TiO 2 and resulting g‐TiO 2 nanoparticles were introduced into poly(ε‐caprolactone) (PCL) matrix to prepare PCL/TiO 2 nanocomposites by in situ polymerization. The effects of b‐TiO 2 and g‐TiO 2 nanoparticles on the structure, morphology, and properties of nanocomposites were characterized and compared. The results showed that the crystalline structure of PCL matrix was not affected significantly by adding b‐TiO 2 or g‐TiO 2 nanoparticles. The g‐TiO 2 nanoparticles had a finer dispersion and better compatibility than bare TiO 2 . The introduction of g‐TiO 2 into PCL matrix increased the crystallization temperature and improved thermal stability of the nanocomposites with respect to untreated TiO 2 . The surface‐treated nanoparticles played an important role in strengthening mechanical properties of the nanocomposites because of its well dispersion and strong interfacial interaction between the nanoparticles and PCL matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012