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Title: Properties of polycarbonate containing BaTiO{sub 3} nanoparticles

The real part of the relative permittivity, ε′, and dielectric loss, tan δ, have been determined at audio frequencies at temperatures from about 5 K to 350 K for nano-composites composed of BaTiO{sub 3} nanoparticles and polycarbonate. The room temperature breakdown strength was also measured and thermal analysis, nuclear magnetic resonance and scanning electron microscopy studies were carried out. For some films the nanoparticles were surface-treated (STNP) while for others they were not (UNP). For concentrations of UNP greater than about 3.4 vol. %, ε′ is much larger than expected on the basis of laws of mixing. On the other hand, ε′ for materials made using STNP is well-behaved. Correspondingly, increased loss (ε″ or tan δ) in the vicinity of room temperature is observed for the materials made from UNP. The anomalously large values of relative permittivity and increased loss are attributed to the presence of large aggregates in the materials made using the UNP. For both UNP-and STNP-based materials, the breakdown strength is found to decrease as nanoparticle concentration increases. The breakdown strength for the materials made using STNP is found to be larger for all concentrations than for those containing UNP despite the presence of large aggregates in some of the STNP-basedmore » materials. This shows that breakdown is strongly affected by the nanoparticle surfaces and/or the interface layer. It is also found that the breakdown strength for materials made using UNP increases as particle size increases. Finally, variable temperature and pressure proton nuclear magnetic resonance relaxation measurements were made to assess the effect of nanoparticle inclusion on polymer motion, and the effects were found to be very minor.« less
Authors:
; ;  [1] ; ; ; ;  [2] ;  [3] ; ; ;  [4]
  1. Chemistry Department, U.S. Naval Academy, Annapolis, Maryland 21402 (United States)
  2. Physics Department, U.S. Naval Academy, Annapolis, Maryland 21402 (United States)
  3. U.S. Naval Research Lab, Washington, DC 20375 (United States)
  4. Department of Physics and Astronomy, Hunter College, New York, New York 10021 (United States)
Publication Date:
OSTI Identifier:
22277905
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; BARIUM COMPOUNDS; COMPOSITE MATERIALS; CONCENTRATION RATIO; DIELECTRIC MATERIALS; INTERFACES; NANOSTRUCTURES; NUCLEAR MAGNETIC RESONANCE; PARTICLE SIZE; PARTICLES; PERMITTIVITY; POLYCARBONATES; PROTONS; SCANNING ELECTRON MICROSCOPY; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; THERMAL ANALYSIS; THIN FILMS; TITANATES