Thermal and dielectric performance of Melt processed Polycarbonate /CaCu 3 Ti 4 O 12 composites (original) (raw)
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Effect on dielectric, structural and thermal behaviour of CaCu 3 Ti 4 O 12 in a Nylon 11 matrix
2019
This paper discusses the probability of obtaining high-dielectric permittivity from ceramic-polymer composites by mixing higher dielectric material, CaCu 3 Ti 4 O 12 (CCTO) in a Nylon 11 matrix by the melt-mixing method. The volume percentage of addition of CCTO micro-particles was from 0 to 20 vol%. The dielectric, structural morphology and thermal properties of the composites were analysed using an impedance analyser, a scanning electron microscope, a differential scanning calorimeter and a thermogravimetric analyser, respectively. The permittivity of 50 vol% of the composite is 12, which is increased to that of virgin Nylon 11 of 5.8. Different theoretical models were employed to rationalize the dielectric behaviour of the composite and found to be accurate with that of the experimental data. The thermal behaviour of the composites was good after the addition of CCTO micro-particles into it. It provides the means to employ the ceramic-polymer composites at low temperature with less permittivity and loss.
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Dielectric Constant of nano-CCTO / Epoxy Composite
Nanocrystalline multiphase CaCu 3 Ti 4 O 12 (CCTO) was prepared using Ca(NO 3 ) 2 .4H 2 O, Cu(NO 3 ) 2 .3H 2 O, TiO 2 and C 2 H 2 O 4 .2H 2 O. The X-Ray differection and SEM analysed of the prepared CCTO powder sintered at 900 o C and 950 o C.
Nylon 6,9/CaCu 3 Ti 4 O 12 (CCTO) nanocrystal composites with relatively high dielectric permittivity (220 at 100 Hz) were fabricated by melt mixing followed by hot pressing. The CCTO nanoceramics were synthesized using the oxalate precursor route, and the transmission electron microscopy studies exhibited that the crystallites are in the range of 20–200 nm. The nanocomposites were characterized using X-ray diffraction, scanning electron micros-copy, thermogravimetric analysis, differential scanning calorimetry, and impedance analyzer to study their structural , thermal, and dielectric properties. The introduction of CCTO nanoparticles into the matrix had influenced the thermal properties. The effective dielectric permit-tivity of the nanocomposite increased by the augmentation of CCTO content in the Nylon 6,9. Our experimental outcomes showed that the fixed dielectric permittivity of such two-phase composite was established above 200 when the CCTO concentration was closer to its percolation threshold. The room temperature dielectric permittivity as high as 220 at 100 Hz has been achieved when the CCTO content increased to 58 vol% in the polymer and this was increased to 3845 at 150°C. The increase in AC conductivity with the increase in the CCTO content in the polymer matrix supported the hopping of the charge carrier conduction mechanism.
Dielectric Constant of nano- CCTO / Epoxy Composit
Nanocrystalline multiphase CaCu 3 Ti 4 O 12 (CCTO) was prepared using Ca(NO 3 ) 2 .4H 2 O, Cu(NO 3 ) 2 .3H 2 O, TiO 2 and C 2 H 2 O 4 .2H 2 O. The X-Ray differection and SEM analysed of the prepared CCTO powder sintered at 900 o C and 950 o C.
Dielectric properties ofPoly(methyl methacrylate) (PMMA)/CaCu3Ti4012 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 CaCu3 Ti4012 (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.
Ceramics International, 2019
Polyaryletherketone (PAEK)/CaCu 3 Ti 4 O 12 (CCTO) nanocomposite films with various (0, 1, 5, 10 and 20) weight% CCTO were fabricated via melt-compounding followed by film extrusion process. The CCTO nanoceramics (nCCTO) with a crystallite size around 30-100 nm were prepared from oxalate precursor route. The thickness of the fabricated films was in the range of 50-80 µm and these films were characterized for their structural, thermal and dielectric behavior. The X-ray diffraction analyses showed the presence of peaks corresponding to both PAEK and CCTO with varying intensities. Fourier transform infrared (FTIR) studies revealed that the chemical structure of PAEK was unaltered by the incorporation of nCCTO. Melting temperature of the pure PAEK was about 372 °C and had not changed significantly with the addition of nCCTO. Thermo-gravimetric analysis was carried out to study the thermal stability of these nanocomposites. Frequency independent dielectric behavior was observed in case of all nanocomposite films. Room temperature dielectric permittivity of PAEK (3.3 at 10 kHz) was enhanced with the addition of nCCTO and for 20 wt% loading a value of 4.5 has been achieved. Low values of dielectric loss (0.005-0.009) were obtained for all nanocomposite films at 10 kHz. These nanocomposites can be explored as possible dielectric materials for capacitor applications.
Fabrication and Characterization of Poly(methyl methacrylate)/CaCu 3 Ti 4 O 12 Composites
Composites comprising Poly(Methyl Methacrylate) (PMMA) and CaCu 3 Ti 4 O 12 (CCTO) via melt mixing followed by hot pressing were fabricated. These were characterized using X-ray diffraction, thermo gravimetric, scanning electron microscopy, and Impedance analyzer for their structural, morphology, and dielectric properties. Composites were found to have better thermal stability than that of pure PMMA. The composite, with 38 Vol % of CCTO (in PMMA), exhibited remarkably low dielectric loss at high frequencies and the low frequency relaxation is attributed to the space charge polarization/ MWS effect. Theoretical models were employed to rationalize the dielectric behavior of these composites. At higher temperatures, the relaxation peak shifts to higher frequencies, due to the merging of both b and a relaxations into a single dielectric dispersion peak. The AC conductivity in the high frequency region was attributed to the electronic polarization. POLYM. ENG. SCI., 54:551-558, 2014. ª
Dielectric behaviour of CaCu3Ti4O12-epoxy composites
Materials Research-ibero-american Journal of Materials, 2008
The dielectric behavior of composite materials (epoxy resin -barium titanate and epoxy -CCTO) was analysed as a function of ceramic amount. Composites were prepared by mixing the components and pouring them into suitable moulds. In some compositions, the matrix was reduced by tetrahydrofuran (THF) incorporation. Samples containing various amounts of ceramic filler were examined by TG/DTA and scanning electron microscopy analysis. Dielectric measurements were performed from 20 Hz to 1 MHz and 30 to 120 °C. It was demonstrated that the epoxy -CCTO composites possessed higher permittivity than classic epoxy -BaTiO 3 composites. However, the low resin permittivity prevailed in the composite dielectric performance.
2014
Studies on the dielectric constant of CaCu 3 Ti 4 O 12 (CCTO) : PET and CaCu 3 Ti 4 O 12: PVC ceramic polymer composites at varying percentages of the polymers was conducted. CaCu 3 Ti 4 O 12 was prepared by the modified solid state reaction method. The dielectric constant (ε') was measured in the frequency range from 10 Hz to 10 6 Hz and the temperature ranging from 30°C to 300°C with the help of HP 4192A LF Impedance Analyzer. The results showed that the dielectric constants of the sample are frequency and temperature dependent. Dielectric constant decreases with increasing frequency and decreasing temperature due to interfacial polarization Keywords-CaCu 3 Ti 4 O 12, dielectric constant, CCTO : PET and CCTO:PVC I.