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Keywords:

  • polymer nanocomposites;
  • novolac;
  • ferroelectric crystal;
  • barium titanate;
  • mechanical properties;
  • broadband dielectric spectroscopy

Abstract

Polymer composites incorporating ferroelectric and piezoelectric crystal particles, randomly distributed within the host matrix, represent a novel class of materials. In this study, composite materials consisted of novolac resin and barium titanate nanoparticles were prepared and examined, varying the nanofiller content. Structural characterization was conducted via X-ray diffraction and scanning electron microscopy. Mechanical and dielectric properties were examined by employing bending and shear strength tests and broadband dielectric spectroscopy, respectively. Bending and shear strength found to decrease with the filler content. Dielectric permittivity was found to increase significantly with filler content, and the detected relaxation processes were attributed to interfacial polarization, glass to rubber transition of the matrix, and reorientation of polar side groups of the polymer chain. Although, the mechanical performance of the examined systems seems not to be attractive in applications due to its brittleness, nanocomposites' dielectric response could be proved interesting in electrical and electronic devices applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012