BaTiO₃ incorporation effect on the dielectric properties of polymer from aqueous emulsion: An enhanced dispersion technique

Abstract

An economic and environment friendly process was adapted to synthesize new dielectric composite materials. Using ethylene vinyl acetate (EVA)/vinyl ester of versatic acid (VeoVa) terpolymer as an aqueous emulsion provides a homogenous dispersion of BaTiO 3 (BT) particles, due to the high viscosity and polarity of the vinyl resin (VR). Composites films were obtained from these dispersions by water evaporation. The evolution of the dielectric properties as a function of the BaTiO 3 content, was correctly fitted by a Maxwell-Garnett model. This fitting of the experimental curve shows a good dispersion of filler in the vinyl resin and the particles separation by a layer of resin as expected for the preparation method used in this study. The VR/BT composites show good synergy between the dielectric properties of the different phases of the composites due to the formation of macrodipoles and to the strong interactions between polar EVA/VeoVa groups and the BaTiO 3 particles surface. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44333.

Toward green three‐phase composites with enhanced dielectric permittivity

“…Figure (a) illustrates that the relative permittivity increases as a function of temperature, due to the orientation polarization of the polar groups of the polymer, as explained in our previous work . Also, the dielectric permittivity of the composites increased with MCC concentration for the whole temperature range.…”

“…Thanks to this analysis, the average size of the aggregates decreases from 3.79 to 1.6 μm 2 with the increase of MCC content from 0% to 4%, respectively. This phenomenon could be explained by the effective interfacial interaction between the three phases, in addition to the hydrophilic character and the high viscosity of the medium (Latex) described in our previous work . In consequence, it is possible to suggest the formation of “microcapacitor networks,” in which the crystalline areas of MCC act as electrodes and the VR/BT serves as the medium, in the same manner as in the case of PI/graphene/BT …”

“…These results are also higher than those previously reported for VR/BT composites. In other words, the BT content of the composite can be relatively reduced from 50 to 20 wt % by adding only 4 wt % of MCC …”

“…Barium titanate BaTiO 3 (BT) was synthesized according to our previous work. It has a diameter of ∼600 nm …”

“…The base material used to prepare ternary composites consisted in a 80/20 blend of VR and BT. The preparation technique of the VR/BT binary composite was described previously . The ternary composite was obtained by adding 1 to 4 wt % MCC to the VR/BT (80/20) blend.…”