Dielectric properties of Poly(methyl methacrylate) (PMMA)/CaCu3Ti4O12 composites

Materials with high dielectric constant are in great demand for the miniaturization of electronic devices. More specifically, high dielectric constant polymer-ceramic composites are useful for embedded capacitor applications. A composite consisting of giant dielectric CaCu₃Ti₄O₁₂ (CCTO) incorporated into the Poly(methyl methacrylate) (PMMA) polymer matrix has been fabricated by melt mixing followed by hot pressing. The composites thus fabricated has been characterised for structural, morphological and dielectric properties. The effective dielectric constant of the composite increased when the CCTO content increased in the PMMA matrix. The dielectric constant permittivity of PMMA is around 4.9 @ 100Hz which has increased to 15.7 @ 100Hz when the ceramic content has increased to 40 Vol %. At low frequency, space charge polarisation is dominant. This composite also exhibited remarkably low dielectric loss at high frequency, which makes this composite a suitable candidate for the capacitors in high frequency application.