Dielectric behaviour and conductivity of high-filled BaTiO3-PMMA composites and the facile route of emulsion polymerization in synthesizing the same
Poly(methyl methacrylate)-BaTiO3 composites were prepared by a combined process of free radical emulsion polymerization and hot pressing. Using a cationic surfactant, emulsion polymerization was proven to be an easy and fast method to synthesize core-shell hybrid particles. By subsequent hot pressing of powders with different amounts of polymers, composites with barium titanate filler contents up to 65 vol% with uniform microstructures could be achieved, as determined by thermogravimetric analysis and scanning electron microscopy. The dielectric properties were characterized for frequencies and temperatures ranging from 100 Hz to 1 MHz and -30 to 80 °C, respectively. Composites exhibited a significant increase in dielectric constant up to 85 with BaTiO3 content and low loss tangents of 0.06 at 1 kHz. Dc conductivity measurements reveal increasing leakage currents with BaTiO 3 contents, enhanced by cationic surfactant influences. © 2013 The Royal Society of Chemistry.
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Hamburg, Behörde für Wissenschaft und Forschung
Joachim Hertz Foundation of the Hamburg Initiative for Excellence in Research (LEXI)