New High-Dielectric-Constant Polymer-Ceramic Composites

摘要

A ceramic-powder polymer composite,making use of a newly developed ceramics-CaCu_3Ti_4O_(12)(CCTO)-that has a giant dielectric constant as the filler,is developed.In this work,poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)] 55/45 mol% copolymer was used as matrix.It is found that the wettability between the copolymer and CCTO is poor,which makes the solution cast composites have a poor uniformity.The uniformity and thus the dielectric constant of the composites can be significantly improved by using hot-press technology to form"sandwich"structure.It is also found that the thermal annealing process can improve the dielectric constant of the composite.The experimental data show that for the flexible composites the dielectric constant at 1 kHz can reach more than 300 at room temperature and more than 700 at approx70 deg C.