Content Of BaTiO3 Research Articles

Piezoelectric performance enhancement of electrospun functionally graded PVDF/BaTiO3 based flexible nanogenerators

Flexible piezoelectric electrospun films have gained widespread attention due to their ability to convert mechanical energy into electrical energy. Pure PVDF has a low output, while multi-layered film based nanogenerators with high concentrations of BaTiO3 give more output. This paper aims to fabricate a functionally graded nanogenerator with varying BaTiO3 concentrations from bottom to top. Multilayer films were synthesized using electrospinning and incorporated into a piezoelectric nanogenerator (PENG) device. The PENG devices were subjected to palm tapping, wrist tapping, and elbow hitting to extract energy. The PENG generated peak-to-peak voltage of 8.22 V, short circuit current of 3.36 µA, and an instantaneous power of 0.14 mW/cm2. Compared to monolayer films, functionally graded films exhibit greater piezoelectric performance as the number of nanofiber layers increases. The piezoelectric output of PENGs device is validated using Comsol Multiphysics software. This study demonstrated the first application of electrospun functionally graded nanostructures as piezoelectric nanogenerators.

Energy storage and ferroelectric properties of flexible 1-x(Na0.5Bi0.5TiO3)-xBaTiO3 thin films on Pt/mica substrates

We investigated the energy storage and ferroelectric properties of flexible 1-x(Na0.5Bi0.5TiO3)-xBaTiO3 (NBT) thin films with BaTiO3 (BT) concentrations ranging from 0 to 6 mol% on Pt/mica substrates depending on the BT concentration. The NBT thin films exhibiting preferentially a-oriented crystallinity on the (111) Pt/mica substrates showed improved leakage current characteristics by increasing the BT concentration. In particular, the NBT thin films with zero BT concentration showed a high remanent polarization of about 28.4 μC/cm2. On the other hand, the NBT thin films with a BT concentration of 6 mol% significantly reduced the remanent polarization to about 4.7 μC/cm2 due to the characteristics of the relaxor. As a result, the NBT thin films with a BT concentration of 6 mol% showed a high energy storage efficiency of 89.5 % with a high recoverable energy storage density of 54.3 J/cm3 and a low loss energy density of 6.3 J/cm3.

Effect of replacement of SiO2 with BaTiO3 on the cadmium calcium-borate glass: Aiming to obtain an active glass for optical and shielding applications

This work has been performed to explore the impact of the incorporation of the inorganic material Barium-Titanate BaTiO3 in the matrix of calciborosilicate glass doped with cadmium cations. Different amounts of BaTiO3 have been introduced to the pure cadmium-calciborosilicate glass at the expense of SiO2 according to the following chemical formula: 30mol%B2O3+20mol%CaO+25mol%CdO+(25−x)mol%SiO2+xmol%BaTiO3 where x = 0, 3, 6, 10. The suggested samples have been obtained using the fast quenching method from their melts at 1250 °C. X-ray diffraction XRD, and FTIR spectra have been used for the structural characterization process of the obtained solids, where the amorphous natures of all samples were confirmed. The increase of BaTiO3 caused the glass’ bulk density to increase from 4.33 g/cm3 (x = 0) to 4.45 g/cm3 (x = 10), as well as it caused an increase in the optical edge, direct bandgap, indirect bandgap, and Fermi energy. For all samples, the optical transmittance, as well as the optical absorbance were not affected by the photon energies in the UVregion, so these samples can be nominated to use as UV- blockers. Moreover, the shielding parameters indicated that the studied cadmium calciborosilicate glass sample with no BaTiO3 is a superior neutron shielding material, because it has the largest value for the effective neutron fast cross-section, while the opposite for gamma where the sample containing the highest content of BaTiO3. It is less valuable for the half-value layer and highest LAC. So we recommend using glass containing 3% of Barium-Titanate BaTiO3 as a radiation shielding material with less size.

Constructing a novel AuAg/BiOBr/BaTiO3 composite via selective decoration route with enhanced visible-light photoatalytic performance

In this work, the BaTiO3 nanoparticles (hole acceptor) were firstly decorated on the surface of BiOBr nanoplates by hydrothermal method, and then AuAg alloy nanoparticles (electron acceptor) are selectively deposited on the uncovered surface of BiOBr nanoplates to form AuAg/BiOBr/BaTiO3 composite using visible-light photodeposition method. It is found that the BaTiO3 (∼55 nm) and AuAg (7–16 nm) nanoparticles are uniformly dispersed on the BiOBr surface, which are disconnected without direct contact between them. The visible-light photocatalytic degradation and reduction activity of products were evaluated using methyl orange (MO), acid orange 7 (AO7), rhodamine B (RhB) and Cr(VI) as the target reactant. After the combination of BiOBr with BaTiO3, the BiOBr/BaTiO3 composites exhibit enhanced photocatalytic activity. When the content of BaTiO3 reaches about 10%, the BiOBr/10%BaTiO3 composite exhibits best photocatalytic efficiency. Notably, the selective deposition of Au, Ag and AuAg alloy nanoparticles leads to the further enhancement of photocatalytic activity for BiOBr/10%BaTiO3 composite, and the optimal photocatalytic activity can be achieved over AuAg/BiOBr/10%BaTiO3 sample. The AuAg/BiOBr/10%BaTiO3 composite is demonstrated to be an stable photocatalyst, which also exhibits efficient synergistic photocatalytic activity for the purification of the RhB/Cr(VI) and AO7/Cr(VI) mixture. The photogenerated charges performance of products was measured by electrochemical work station. The main active species participated in the photocatalytic reaction of AuAg/BiOBr/10%BaTiO3 was detected. Based on above results, the synergistic modification mechanism of BaTiO3 and AuAg alloy nanoparticles on the photocatalytic activity of BiOBr was proposed.

Enhanced energy storage performance of PVDF composite films with a small content of BaTiO3

Enhanced energy storage performance of PVDF composite films with a small content of BaTiO3

PVDF-BaTiO3 Nanocomposite Inkjet Inks with Enhanced β-Phase Crystallinity for Printed Electronics.

Polyvinylidene difluoride (PVDF) and its copolymers are promising electroactive polymers showing outstanding ferroelectric, piezoelectric, and pyroelectric properties in comparison with other organic materials. They have shown promise for applications in flexible sensors, energy-harvesting transducers, electronic skins, and flexible memories due to their biocompatibility, high chemical stability, bending and stretching abilities. PVDF can crystallize at five different phases of α, β, γ, δ, and ε; however, ferro-, piezo-, and pyroelectric properties of this polymer only originate from polar phases of β and γ. In this research, we reported fabrication of PVDF inkjet inks with enhanced β-phase crystallinity by incorporating barium titanate nanoparticles (BaTiO3). BaTiO3 not only acts as a nucleating agent to induce β-phase crystallinity, but it also improves the electric properties of PVDF through synergistic a ferroelectric polarization effect. PVDF-BaTiO3 nanocomposite inkjet inks with different BaTiO3 concentrations were prepared by wet ball milling coupled with bath ultrasonication. It was observed that the sample with 5 w% of BaTiO3 had the highest β-phase crystallinity, while in higher ratios overall crystallinity deteriorated progressively, leading to more amorphous structures.

Structural, multiferroic, and magnetoelectric properties of (1 − x)Bi0.85La0.15FeO3–xBaTiO3 composite ceramics

Multiferroic magnetoelectric composites are beneficial in device fabrication because of their tunable ferroelectricity and magnetism. The partial substitution in bismuth ferrite (BiFeO3) is one of the best possible ways for synthesizing pure phase BiFeO3-based materials. A comprehensive study of (1 − x)Bi0.85La0.15FeO3–xBaTiO3 (x = 0–0.3) was done by coalescing ferroelectric, dielectric, magnetic, and magnetoelectric properties with structural and microstructural characterizations to explore the effect of BaTiO3 (BT) into Bi0.85La0.15FeO3 (BLFO) and forming composite ceramics. The X-ray diffraction study reveals the phase purity in BLFO and a structural transformation from rhombohedral to cubic phase with increasing content of BT. The Raman spectroscopy and scanning electron micrographs confirm the co-existence of composite formation in BLFO–xBT. The Raman modes shift towards lower wavenumber with increasing BT concentration suggests lattice compression. The room temperature M–H hysteresis curve shows the existence of weak ferromagnetism in BLFO–BT composites and superparamagnetism in BLFO–10BT ceramic. The curve fitting of M–H curve for BLFO–10BT showed the existence of superparamagnetic particles. The ferroelectric hysteresis P–E loop measurements produced unsaturated oval-shaped loops with high leakage and displayed a lossy dielectric nature. The effect of magnetic field on polarization versus electric field curve reveals the interfacial interaction due to the origin of magnetoelectric interaction in BLFO–BT composite ceramics. All the samples display peak broadening in temperature–permittivity plot and confirm relaxor behavior. The superparamagnetic behavior and magnetic field-dependent energy storage capacity of BLFO–10BT composite ceramic make this material a potential candidate for magnetoelectric devices.

Design of lead-free PVDF/CNT/BaTiO3 piezocomposites for sensing and energy harvesting: the role of polycrystallinity, nanoadditives, and anisotropy

Lead-free piezoelectric composites with polymeric matrices offer a scalable and eco-friendly solution to sensing and energy harvesting applications. Piezoelectric polymers such as PVDF are particularly interesting because of the possibility to engineer the performance of these materials through addition of higher-performance piezoelectric inclusions and nanomaterials and to scalably manufacture such composites by emerging techniques such as 3D printing. This work makes two contributions, namely towards composite design and towards development of accurate effective property models. In the context of composite design, we evaluate the piezoelectric performance of PVDF modified by the addition of polycrystalline-BaTiO3 and multiwalled carbon nanotubes. Firstly, the addition of BaTiO3 dramatically improves the electric field within the composite offering significant advantages specially at low BaTiO3 concentrations. Secondly, the addition of carbon nanotubes to the matrix, particularly at higher BaTiO3 loadings, leads to an order of magnitude increase in the piezoelectric flux generation. Further enhancement in the flux generation is also possible by tuning the polycrystallinity of the BaTiO3 inclusions. However, these behaviours are inclusion-driven and the piezoelectric behaviour of the matrix does not contribute to this improvement. Importantly, a small addition of BaTiO3 and CNT into the PVDF matrix, away from percolation, can simultaneously improve flux and electric field generation. In this part of the work, we assume an isotropic PVDF matrix. Given that PVDF is elastically anisotropic, the second aspect of this work is the development of an effective property model for CNT-modified PVDF, taking into account the elastic anisotropy of poled PVDF, to predict the elastic coefficients of CNT-modified PVDF matrices, thus undertaking a key step towards modelling anisotropic piezoelectric composites. We show that the anisotropy-based model makes similar predictions in the effective composite behaviour, indicating that in the case of PVDF-based piezocomposites, the anisotropy of the matrix does not significantly affect the piezoresponse.

Plasma fluorination of BaTiO3 for enhancement of interfacial adhesion and surface insulation of epoxy resin

Composite dielectrics with excellent electrical properties are integral to today’s energy industries and power infrastructure. Epoxy resin filled with inorganic nano-fillers has been extensively studied for its excellent performances. In this paper, barium titanate (BaTiO3) nanoparticles are selected as the fillers and fluorinated by plasma treatment. The morphology, element content and chemical bond of BaTiO3 and fluorinated BaTiO3 fillers are characterized by SEM, EDS, XPS and FTIR, respectively. The influence of filler concentration and fluorination on flashover voltage of epoxy resin composites was studied. We found that the fluorinated BTO could improve the compatibility of filler and matrix and surface insulation of epoxy resin composites. Finally, the relationship between filler concentration, dielectric constant, fluorination treatment and charge dissipation was analyzed, and the trap distribution on the surface of composites was calculated by isothermal surface potential decay method. Fluorinated BaTiO3 particles as fillers blended with epoxy resin have great engineering application potential.

Preparation and characterization of BaCo0.5Nb0.5O3-based new high temperature NTC sensitive ceramics

A new type of high temperature NTC thermal sensitive ceramics BaCoxNbxTi(1−2x)O3 (BCNT) was synthesized via a solid-state reaction process. The as-prepared ceramics were obtained by sintering at 1300 °C for 1 h in air. According to the XRD and SEM analysis, BCNT form a solid solution with cubic phase, and the content of BaTiO3 (BT) has insignificant influence on the mean grain size of the ceramics. The BaCo0.5Nb0.5O3 (BCN) based materials show typical NTC effect in the whole temperature measuring range (25–500 °C). The room temperature resistivity (ρ25), thermal constant (B25/85) and activation energy (Ea) increase monotonously with the increase of BT content. The TG-DSC results show that there is no phase transition in the temperature range from 25 to 1000 °C, which indicate that the structure of the BCN-based ceramics is stable at high temperature.

Synthesis and Characterization of BaTiO₃/Polypyrrole Composites with Exceptional Dielectric Behaviour.

Higher concentrations of ceramic fillers induce brittleness in the ceramic/polymer hybrids which restrict their applications to limited fields especially when such hybrids are prepared for their use as dielectrics. We have synthesized and characterized different BaTiO3-polypyrrole (PPy) composites by changing the concentration of BaTiO3 from 1% by weight of PPy taken to 5 wt % to explore its effect on the dielectric parameters of the final product and found that the BaTiO3-polypyrrole composite with weight ratio of 0.05:1 exhibited highest dielectric constant, lowest dielectric loss and thermally most stable. All the composites were prepared using in-situ polymerization of pyrrole in an aqueous dispersion of low content of BaTiO3 in the presence of small amount of Hydrochloric acid. These composites were characterized for their microstructure and crystallinity by X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) while thermal stability by thermo gravimetric (TGA) analysis. An impedance analyser (LCR meter) was utilized to investigate the dielectric parameters. FT-IR data confirmed the presence of the two phases and their interaction, inferred from the shifting of normal PPy peaks. The data obtained from XRD confirmed the presence of crystallites of 2.8 to 5 nm with dominant crystallinity of the filler, TGA analysis (25 to 600 °C) confirmed the higher thermal stability induced on successive addition of the filler into the prepared composites as compared to that of pure PPy in a wide temperature range which is unusual for such a low % age addition of the filler. The SEM analysis together with XRD results reveal that the successive introduction of BaTiO3 particles produced crystallites of 2 to 5 nm size which bonded together and changed the hemispherical shaped larger grains of the matrix to regular shaped smaller grains. The dielectric constant of the composites was enhanced with filler contents from 178 to 522 at 1 MHz for 1 wt % and 5 wt % BaTiO3 respectively. It was concluded that the introduction of BaTiO3 into the polymer matrix with this new procedure has greatly affected the polymerization process, thermal stability, morphology and dielectric properties of the host matrix and has resulted in a novel series of the composites which may have broad applications.

Detection of deformation induced electromagnetic radiation from cement- barium titanate composite under impact loading

Electromagnetic radiation (EMR) responses from cement–BaTiO3 (BT) composites under impact loading have been presented in this paper. The bulk density, dielectric constant and piezoelectric charge coefficient of the cement-BT composites are observed to increase while the loss tangent decreases with increase in BT content in the composites. Measurements have been carried out using cylindrical, semi-cylindrical and quarter cylindrical antennae. Marked enhancement in the values of EMR voltage for all experiments at different heights of impact and with different antennae is observed as the content of BT is increased from 5% to 40% in the cement–BT composites. The EMR voltage increases, respectively from 0.58 V to 1.16 V, 384–732 mV and 259–520 mV for cylindrical antenna, semi-cylindrical antenna and quarter cylindrical antenna with the increase in BT content from 5% to 40% in cement–BT composites at the same level of impact (height of impact = 21 cm). Also average EMR energy release rate increases from 0.00007 V2–sec/sec to 0.00047 V2–sec/sec, 0.000065 V2 – sec/sec to 0.000214 V2 – sec/sec and 0.000032 V2 – sec/sec to 0.000135 V2 – sec/sec with the increase in BT content from 5% to 40% in cement–BT composites impacted from a height of 21 cm as measured by cylindrical antenna, semi-cylindrical antenna and quarter cylindrical antenna respectively. The EMR voltage is observed to decrease smoothly initially and then attain constancy with increase in distance of measurement location from the sample. In addition, the EMR responses were found to be proportional to the height of impact in all the cement–BT composites indicating that EMR measurement technique can effectively be used for structural health monitoring.

Thermomechanically stable dielectric composites based on poly(ether ketone) and BaTiO3 with improved electromagnetic shielding properties in X‐band

ABSTRACTHigh‐performance barium titanate (BaTiO3) filled poly(ether ketone) (PEK) composites were prepared by melt compounding with an aim to investigate the effect of BaTiO3 on thermal, thermomechanical, dielectric, and electromagnetic interference shielding behavior of PEK. The content of BaTiO3 in the PEK matrix was varied from 0 to 18 vol %. Scanning electron microscopy studies shows that BaTiO3 particles were uniformly distributed in the PEK matrix up to 13 vol % loading followed by the formation of agglomerates at higher loading (18 vol %). Rockwell hardness increased up to 13 vol % loading followed by a decrease at 18 vol % loading. Dynamic mechanical analysis revealed that storage modulus increases with increase in BaTiO3 loading with a maximum value of 3192 MPa at 13 vol % compared to 2099 MPa for neat PEK. Dielectric constant of composites measured in the frequency range of 8.2–12.4 GHz increased approximately three times upon incorporation of 18 vol % of BaTiO3. This increment in dielectric constant is reflected in improved electromagnetic shielding properties as loading of dielectric filler (BaTiO3) increases. Total shielding effectiveness of −11 dB (∼92% attenuation) at loading of 18 vol % BaTiO3 justifies the use of these composites for suppression of EM radiations. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46413.

Secondary dispersion of BaTiO3 for the enhanced mechanical properties of the Poly (arylene ether nitrile)-based composite laminates

Secondary dispersion of the nano barium titanate (BaTiO3) was performed to obtain the fiber-reinforced polyarylene ether nitrile-based (PEN) composite laminates with improved mechanical properties. BaTiO3/PEN composite films were prepared via casting with ultrasonic dispersion, and then the glass fiber-reinforced (GF) composite laminates were obtained by the hot-melting method, which were favored to realize the secondary dispersion of the BaTiO3 nanoparticles. The fracture surface of the BaTiO3/PEN films and BaTiO3/PEN/GF composite laminates investigated by SEM showed that the BaTiO3 dispersed homogenously both in the PEN matrix and the gaps between the fibers. The mechanical and thermo-mechanical properties of the laminates were characterized and results indicated that the nano-BaTiO3 particles and fibers show enhanced synergistic effects. That is, with increasing the BaTiO3 content, the flexural strength and modulus of the composite laminates increased correspondingly, as well as the glass transition temperatures. Additionally, with the introduction of nano-BaTiO3 particles, the dielectric constants (>5.5 at 1 kHz) of the composite laminates were improved obviously and the low dielectric loss (˂0.02 at 1 kHz) was maintained. The temperatures at weight loss 5% (T5%) of all the composite laminates with various content of BaTiO3 were over 490 °C both in N2 and air atomosphere. Good dielectric properties and outstanding thermo-mechanical properties would enable the PEN-based fiber-reinforced composite laminates as the candidates in the material fields of structure-functional integrations.

Stabilization of the NOP ferroelectric phase in potassium nitrate–barium titanate ferroelectric composites

The study of temperature evolution of KNO3 (NOP) structure in ferroelectric (1−x)KNO3 + (x)BaTiO3 composites with BaTiO3 concentrations х = 0.25, 0.50 and 0.53 has been carried out on cooling with the use of the neutron diffraction technique. It was shown that, on cooling, the phase transition temperature (Tc) from the high-temperature paraelectric phase into the ferroelectric one did not depend on barium titanate concentration and practically coincided with Tc for pure NOP. Moreover, it was found that the admixture of BaTiO3 essentially enlarged the temperature range of NOP ferroelectric phase stability in the composites with BaTiO3 concentrations x = 0.25 and 0.50. The suppression of the ferroelectric phase was observed for the composite with x = 0.53.

Effects of content and surface hydrophobic modification of BaTiO3 on the cooling properties of ASA (acrylonitrile-styrene-acrylate copolymer)

For the field of cool material, barium titanate (BaTiO3, BT) is still a new member that needs to be further studied. Herein, the effects of both content and surface hydrophobic modification of BT on the cooling properties of acrylonitrile-styrene-acrylate copolymer (ASA) were detailedly investigated, aiming to fabricate composited cool material. Butyl acrylate (BA) was employed to convert the surface of BT from hydrophilic to hydrophobic. The addition of unmodified BT could significantly improve the solar reflectance of ASA, especially when the addition amount is 3 vol%, the near infrared (NIR) reflectance increased from 22.02 to 72.60%. However, serious agglomeration occurred when the addition amount increased to 5 vol% and therefore led to a relatively smaller increase in solar reflectance and an obvious decline in impact strength. After surface hydrophobic modification, the modified BT (M-BT) presented better dispersibility in ASA matrix, which contributed to the improvement of both solar reflectance and impact strength. In addition, the temperature test provided a more sufficient and intuitive way to evaluate the cooling effect of the composited cool materials, and a significant decrease (over 10°C) could be achieved in the temperature test when M-BT particles were introduced.

Structure and dielectric properties at phase transition of Na1/2Bi1/2TiO3-BaTiO3 solid solutions

ABSTRACTPhase coexistence region is studied by x-ray diffraction for Na1/2Bi1/2TiO3-BaTiO3 solid solutions in the tetragonal phase side from the morphotropic phase boundary. The first order ferroelectric phase transition, determined from a jump in the temperature dependence of dielectric permittivity, is located inside the coexistence region of cubic and tetragonal phases and is below the temperature, where tetragonality disappears. At low BaTiO3 concentrations phase transition into ferroelectric state at cooling is slowly approached in time and is smeared over large temperature range. Rietveld method, applied for more precise evaluation of phase content, reveals large local deformations inside the ferroelectric phase.

A Lithium Stable High Lithium Ion Conducting Solid Electrolyte of Li1.4Al0.4Ge0.2Ti1.4(PO4)3 Coated with Thin Polymer Film

In recent years, high lithium ion conducting solid electrolytes have appealed to many researchers due to their outstanding performance in safety and electrochemical stability in comparison to the flammable liquid electrolyte, which is widely used in current lithium-ion batteries1. A large number of solid electrolytes have been reported over the past several decades such as Li3N, Li3.25P0.95S4, Li10GeP2S12, Li1.4Al0.4Ge0.2Ti1.6(PO4)3 and Li7La3Zr2O12 whose electrical conductivities are all more than 10-4 S cm-1 at 25 oC. Among them, Li1.4Al0.4Ge0.2Ti1.6(PO4)3 (LAGTP) exhibits the most prominent potential as an electrolyte in various kinds of batteries because of its high conductivity (10-3 S cm-1 at room temperature), excellent stability in atmosphere, and the ease with which it can be prepared into thin films2; however, the main obstacle to its development and application in batteries is the instability of the interface between LAGTP and lithium electrode, which is attributed to the reduction reaction of Ti4+ by metal lithium. Li3N and polymer protective layers are typically introduced into the architecture design of electrolytes to address this problem by spatially separating LAGTP and lithium electrode. Even though polymer electrolytes are well known for their relatively low conductivity at room temperature, their brief and adjustable preparation process is still considered as a major advantage. In this study, a novel composite electrolyte of lithium stable polymer and water impermeable LAGTP was proposed. This composite solid electrolyte consisted of a thin lithium stable polyethylene oxide (PEO) based polymer film and a high lithium ion conducting LAGTP film. The LAGTP film was prepared via the tape casting method in which the preceding fine powder was synthesized via the sol-gel method. Afterwards, epoxy resin gradually grew in the pores of the LAGTP film through polymerization with polymer monomers at 170 oC for 24 hours. A PEO solution dispersed in acetonitrile with lithium bis(fluorosulfonyl)imide (LiFSI), tetraethylene glycol dimethyl ether (G4) and the fine powder of BaTiO3 was gradually dropped on the surface of the LAGTP films, where the mole ratio of PEO/LiFSI/G4 was 8/1/2 and the content of BaTiO3 was 10 wt%. The composite solid electrolyte with 4 wt% PEO based electrolyte showed a high electrical conductivity of about 1×10-4 S cm-1 at 25 oC and 6×10-4 S cm-1 at 60 oC. The composite electrolytes also displayed a good stability with metal lithium and suppressed the formation of the lithium dendrite in the cell of Lithium/composite electrolyte of PEO coated LAGTP/Lithium at 1.0 mA cm-2for 40 h at room temperature. This lithium-stable and water-insensitive composite solid electrolyte with high ion conductivity is most likely to become an attractive candidate for all solid lithium batteries and lithium-air batteries in the near future.

Reinforced properties of ethylene–propylene–diene monomer composites by vinyltrimethoxysiloxane functionalised barium titanate

In this study, non-conductive ethylene–propylene–diene monomer (EPDM)/barium titanate (BaTiO3) composites with high dielectric constant and low dielectric loss are prepared. Fourier transform infrared (FT-IR) spectra show the chemical adherence of vinyltrimethoxysiloxane oligomer (SG-Si6490) to the surface of BaTiO3 particles. Functionalised BaTiO3 particles have better compatibility with EPDM matrix and promote the cure properties of EPDM composites. It is found that when the content of BaTiO3 increases to 40 vol.-%, the resistivity, rheological, dielectric and mechanical properties of EPDM/BaTiO3 composites change drastically. The dielectric constant of EPDM with 50 vol.-% BaTiO3 at 10 MHz is 15, which is 7.5 times higher than that of EPDM control. Meanwhile, the volume resistivity results show EPDM with 50 vol.-% BaTiO3 is still non-conductive. As for mechanical properties, the tensile and tear strength of EPDM control increase from 1.45 MPa and 8.73 kN m−1 to 10.02 MPa (about seven times higher) and 24.65 kN m−1 (about three times higher), respectively.

Preparation and properties of BaTiO3 filled butyl rubber composites for flexible electronic circuit applications

Butyl rubber–micron barium titanate (BR/BT) and butyl rubber–nano barium titanate (BR/nBT) composites were prepared by sigma mixing followed by hot pressing. The tensile tests show that both the composites were mechanically flexible. The microwave dielectric properties of both BR/BT and BR/nBT composites were investigated as a function of ceramic loading and were found to be improved with filler content. The butyl rubber has a relative permittivity (er) of 2.4 and loss tangent (tan δ) of 0.0017 at 5 GHz. At a filler loading of 0.24 volume fraction (vf) of micron sized barium titanate (BaTiO3) powder loading, the composite attained a er of 7 and tan δ of 0.014 and for the same filler content of nano BaTiO3 the composite have er of 8.9 and tan δ of 0.019 at 5 GHz. The thermal and mechanical properties of both the composites were investigated. The experimental values of er of both BR/BT and BR/nBT composites for different volume fractions were compared with theoretical models.