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Nickel niobate (NiNb2O6) was used to modify the barium titanate (BaTiO3) ceramics, the obtained NiNb2O6‐BaTiO3 ceramics possess better dielectric performances than that of raw BaTiO3. By adding NiNb2O6‐BaTiO3 into poly(arylene ether nitriles) (PEN) polymer, a series of NiNb2O6‐BaTiO3/PEN composite films with different NiNb2O6‐BaTiO3 contents were prepared via solution casting method. The morphology, thermal, mechanical, dielectric properties, and flexibility of the obtained NiNb2O6‐BaTiO3/PEN composite films were investigated detailedly. As the filler content increases, the tensile modulus of NiNb2O6‐BaTiO3/PEN composite films increases gradually, while the tensile strength decreases. Thermal and flexibility analysis shows that the addition of the NiNb2O6‐BaTiO3 fillers does not affect the thermal and flexibility properties endowed by the PEN matrix. The dielectric constant of the composites almost linearly increases from 3.7 (1 kHz) to 15.3 (1 kHz) as the filler content increases from 0 to 40 wt%. Besides, results show that NiNb2O6‐BaTiO3/PEN composites exhibit higher dielectric constant than that of BaTiO3/PEN. The as‐prepared NiNb2O6‐BaTiO3 will be a more promising filler to prepare polymer‐ceramic composites for organic film capacitors. [ABSTRACT FROM AUTHOR]

In order to prepare polymer dielectric materials with high energy storage density, a series of polyimide (PI) based Janus composite films were prepared by metal–organic frameworks (MOFs) material (UiO‐66) with high dielectric constant (ɛr) and boron nitride nanosheets (BNNSs) with high breakdown strength (Eb). As reported, the UiO‐66 can significantly improve the ɛr of the composites. The ɛr of 20 wt% UiO‐66/PI film is 10.51 at 103 Hz, which is 3.1 times that of pure PI film (3.39 at 103 Hz). However, the Eb of 20 wt% UiO‐66/PI is only 58 MV m−1, which is only 16.51% of pure PI (352 MV m−1). The sharp decline in Eb reduces the energy storage capacity of the composites. To solve this problem, first, BNNSs with an average diameter of 2 μm and a thickness of 1.36 nm (about 4–5 layer) were obtained by hydrothermal reflux stripping. BNNSs/PI//UiO‐66/PI Janus composite films with double‐layer structure were prepared by directly casting BNNSs/PI on the surface of UiO‐66/PI. For 0.3 wt% BNNSs/PI//10 wt% UiO‐66/PI, the calculated energy storage density (Ue) is 5.75 J cm−3 at 140 MV m−1, which is 3.57 times that of pure PI film (1.61 J cm−3 at 140 MV m−1). Meanwhile, the charge discharge efficiency is 82.55% (at 140 MV m−1). Highlights: BNNSs prepared by hydrothermal reflux stripping have fewer layers.BNNSs/PI composites improve the Eb of UiO‐66/PI composites by Janus structure.The Ue of BP‐0.3//UP‐10 composites with Janus structure was 5.75 J cm−3. [ABSTRACT FROM AUTHOR]

Barium titanate (BT) nanoparticles were surface coated by a silane coupling agent (KH550) and core–shell structured nanoparticles (named KH550@BT) were obtained. Similarly, BT nanoparticles coated by polydopamine (PDA) were named as PDA@BT. Meanwhile, boron nitride (BN) nanosheets (BNNS) were successfully unstripped from block BN. Then, two kinds of ternary poly(arylene ether nitrile) (PEN)‐based composites are prepared using the solution casting method. Composites with 30 wt% KH550@BT and 12 wt% BNNS were named as KH550@BT/BNNS/PEN. Composites with 30 wt% PDA@BT and 12 wt% BNNS were named as PDA@BT/BNNS/PEN. The microstructure, dielectric properties, and energy storage properties of the ternary composites were studied in detail. PEN embedded with either BNNS or BT were prepared and studied for comparison. As a result, the introduction of BT will improve the dielectric constant (εr) and energy storage density (W), but it will reduce the breakdown strength (Eb) and charge–discharge efficiency (η) of composites. BNNS not only improves Eb and W but also improves η of composites. Although the introduction of BT and BNNS simultaneously may reduce η, it will improve εr, Eb, and W of composites. Most importantly, the fast discharge speed and high power density demonstrate that the BT/BNNS/PEN composites are potential candidates to be used in high power pulsed capacitors fields. Highlights: Boron nitride nanosheets improve the breakdown strength of composites.The composites achieve simultaneous increment of εr and Eb.The power density of the BT/BNNS/PEN composites was higher than 70 MW cm−3. [ABSTRACT FROM AUTHOR]

Firstly, the BaTiO3 nanoparticles were coated with a layer of paraffin, forming a core shell structure. Then, as‐prepared paraffin@BaTiO3 nanofillers were directly blended with polyimide (PI) prepolymer to fabricate paraffin@BaTiO3/PI composite films. The microstructure, thermal, and dielectric properties were investigated in detail. The surface‐modified paraffin@BaTiO3 nanoparticles exhibited a typical core shell structure with uniform and complete coverage. The char yield of the composite film with 10 wt% paraffin@BaTiO3 increased from 56.40% to 70.73%. It is obvious that the paraffin@BaTiO3 nanofillers have a positive effect on ablative performance of the composite film. Compared with pure PI, the εr of paraffin@BaTiO3/PI composites with 40% mass fraction increased from 3.41 to 9.35 (1 kHz). The tanδ of paraffin@BaTiO3/PI composites was just 0.0065 (1 kHz) when the filler loading was 40 wt%. Temperature dependency of the permittivity of the composites reveals a zero‐temperature‐coefficient from 80°C to 180°C. [ABSTRACT FROM AUTHOR]

Nanosilica/polyarylene ether nitriles terminated with phthalonitrile (SiO2/PEN- t-Ph) composites were prepared by hot-press approach. To ensure the nano-SiO2 can disperse uniformly, the solution casting method combined with ultrasonic dispersion technology had been taken previously. The mass fraction of nano-SiO2 particles was varied to investigate their effect on the thermal, mechanical, and dielectric properties of the nanocomposites. From scanning electron microscope images, it was found that the nanoSiO2 particles were dispersed uniformly in the PEN- t-Ph matrix when the addition of nano-SiO2 was less than 16.0 wt%. However, when the mass fraction of nano-SiO2 increased to 20.0 wt%, the nano-SiO2 particles tend to self-aggregate and form microns sized particles. Thermal studies revealed that nano-SiO2 particles did not weaken the thermal stabilities of the PEN- t-Ph matrix. Mechanical investigation manifested that the SiO2/PEN- t-Ph nanocomposites with 12.0 wt% nano-SiO2 loading showed the best mechanical performance with tensile strength of 108.2 MPa and tensile modulus of 2107.5 Mpa, increasing by 14% and 19%, respectively as compared with the pure PEN- t-Ph film. Dielectric measurement showed that the dielectric constant increased from 3.70 to 4.15 when the nano-SiO2 particles varied from 0.0 to 20.0 wt% at 1 kHz. Therefore, such composite was a good candidate for high performance materials at elevated temperature environment. POLYM. COMPOS., 35:344-350, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]