Structural and dielectrical properties of PMMA/TiO2 composites in terms of free volume defects probed by positron annihilation lifetime spectroscopy

KAYA A. U., Kösem G., YENER M. D., TAV C., YAHŞİ U., ESMER K.

Polymers and Polymer Composites, vol.29, pp.107-116, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29
  • Publication Date: 2021
  • Doi Number: 10.1177/0967391120903533
  • Journal Name: Polymers and Polymer Composites
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.107-116
  • Keywords: PMMA, TiO2, composite, dielectric properties, UV-visible, free volume, positron annihilation lifetime spectroscopy
  • Marmara University Affiliated: Yes

Abstract

A suspension of ultrasonically agitated Titanium dioxide micrometer-sized powder has been introduced into a poly(methyl methacrylate) (PMMA) matrix by solvent (CHCl3) mixing under slow mechanical stirring, and the resulting suspension was used to cast free-standing PMMA/TiO2 composite films. Filler contents from 0 wt% to 7.5 wt% were selected, since TiO2 particles could not be previously suspended in chloroform at higher concentrations by ultrasonic agitation. Optical and dielectric properties of composites were determined by ultraviolet (UV)-visible and dielectric spectrometry. In the UV region, 450% improvement of UV absorption was achieved in the TiO2/PMMA composite compared with neat PMMA. The structural properties and hole-free volume of the composites were determined by X-ray diffractometry and positron annihilation lifetime spectroscopy, respectively. The particle size and homogeneous dispersion of the particles in the polymer matrix were related to the hole-free volume of the PMMA.