POLYMER COMPOSITES
·
2026
·
IF 4.9
Li Diao,Ziyuan Wang,Han Wu,Xin Hao Xu,Linying Xiong,Ya Peng
Core–shell CaCu 3 Ti 4 O 12 @Al 2 O 3 (CCTO@Al 2 O 3 ) fillers were synthesized via a hydrothermal method and subsequently functionalized with KH550 to obtain K-CCTO@Al 2 O 3 . The formation of the core–shell structure was confirmed by transmission electron microscopy (TEM), while the successful grafting of KH550 and the presence of a stable interfacial layer were further verified by FT-IR spectroscopy, X-ray diffraction (XRD), surface energy measurements, and particle size analysis. Polyimide (PI) composites were fabricated through in situ polymerization of 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) and 4,4′-oxydianiline (ODA), with various loadings of K-CCTO@Al 2 O 3 incorporated into the matrix. The dielectric, mechanical, water resistance, breakdown strength, and thermal properties of the resulting PI composite films were systematically investigated. Among all samples, the composite containing 10 wt% K-CCTO@Al 2 O 3 showed the best overall performance, showing a dielectric constant of 8.93 at 1 kHz before water absorption and 9.10 after water absorption, with dielectric loss remaining below 0.01 under both conditions. In addition, this composite exhibited a tensile strength of 117.41 MPa, a breakdown strength of 246.1 kV/mm, improved thermal stability, and excellent water resistance. The KH550 functionalization renders the filler surface energy closer to that of the PI matrix, thereby enhancing interfacial compatibility and promoting more uniform filler dispersion. Consequently, interfacial defects are effectively suppressed, facilitating more efficient charge transport and stress transfer within the composite. This study demonstrates that combining the core–shell structure with surface functionalization is an effective approach for developing high-performance dielectric polyimide composites. Highlights KH550 was applied to modify core–shell CCTO@Al 2 O 3 fillers. Dielectric composites were prepared from K-CCTO@Al 2 O 3 and polyimide. The KH550 treatment improved the dispersion of K-CCTO@Al 2 O 3 fillers in PI. K-CCTO@Al 2 O 3 improved dielectric and mechanical performance for the optimized loading.
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Chao Xu,Xuetong Zhao,Lulu Ren,Jianjie Sun,Lijun Yang,Jing Guo,Ruijin Liao
Highly dense CaCu 3 Ti 4 O 12 (CCTO) ceramics co-doped by ZnO and Al 2 O 3 were synthesized by spark plasma sintering (SPS) at 750 °C for 10 min, and then annealed at 1000 °C for 3 h. The homogeneous microstructures were achieved, and the grain size was suppressed to around 2 μm. Dramatically enhanced electrical properties of CCTO ceramics were obtained when 1 mol% ZnO and Al 2 O 3 were co-doped. The breakdown field was improved to 12.13 kV/cm and the nonlinear coefficient was increased to 6.59, accompanying with a low dielectric loss of 0.02 at around 1 kHz, which were ascribed to the elevation of Schottky barrier height from 0.54 eV to 0.80 eV. Comparing with the pure CCTO sample, the activation energy of grain boundary obtained from the impedance spectra increases from 0.64 eV to 0.92 eV. Additionally, the grain and grain boundary resistance were also discussed based on the Cole-Cole plot, from which the grain boundary resistance was found to be increased significantly from 3.8 × 10 5 Ω to 4.0 × 10 6 Ω after co-doping.
研究领域:
材料科学
·
陶瓷
·
电气工程
·
固体物理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
El Houcine Lahrar,Abdechafik EL Harrak,El Hassan Yahakoub,Amine Bendahhou,Hafida Essaoudi,Abdessamad Faik
Barium-doped calcium copper titanate ceramics Ca 1-x Ba x Cu 3 Ti 4 O 12 with x = 0, 0.05, 0.1 and 0.2 were synthesized by the conventional solid-state method. We studied the effects of substituting Ca for Ba in the perovskite compound CCTO on structural evolution and electrical responses by changing the value of x. Processing the results of X-ray diffraction analysis using the Rietveld refinement method revealed that all the powders of the compounds studied in this work present a single perovskite phase with cubic symmetry of the Im 3 ‾ space group. SEM analysis revealed that Ba doping promotes a reduction in grain size and a more uniform grain distribution. Complex impedance analysis highlighted a marked reduction in grain boundary resistance and an increase in relaxation time with Ba substitution. Dielectric measurements shows that all the doped ceramics have a lower dielectric permittivity value (ε r ) than CCTO, due to the low grain boundary resistivity of the barium-doped compounds. AC conductivity showed frequency-dependent behavior consistent with hopping conduction mechanism, while barium doping reduced conductivity, due probably to lower carrier mobility and finer grain size. The breakdown field (E b ) and the non-linear coefficient (α) were significantly improved with Ba doping, reaching maximum values of 5.01 kV/cm and 7.45, respectively.
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产品关联
DOI
高影响因子
BULLETIN OF MATERIALS SCIENCE
·
2023
·Vol. 46
·期 4
·1-11
·
IF 1.8
Chen Keren,Wang Xinhua,Jiang Junhao,Zuo Peiyuan,Liu Xiaoyun,Zhuang Qixin
Carbon nanotubes (CNTs) due to their outstanding features, such as unique electronic properties and large specific surface areas, have been intensively studied as nanoscale fillers to improve the permittivity of polymer dielectrics. However, due to the unfavourable formation of conductive channels, these CNTs-derived nanocomposites usually suffer from high dielectric loss and low breakdown strength, therefore greatly restricting their practical applications. In this work, we modified pristine multiwalled carbon nanotubes (MWCNTs) by chemical oxidation to prepare partially unzipped carbon nanotubes (PUCNTs), which not only retained excellent electrical properties but also enhanced interfacial interactions with polymers. The obtained PUCNTs/poly(vinylidene fluoride) (PVDF) nanocomposites exhibit higher permittivity and lower dielectric loss compared to raw MWCNTs added. To further alleviate the detrimental influence of conductive channels, we have designed a new class of hybrid composed of PUCNTs-decorated CaCu 3 Ti 4 O 12 nanoparticles (PUCNTs-CCTO) and their PVDF-based nanocomposites. At 1 kHz, the PUCNTs-CCTO/PVDF nanocomposite filled the ternary nanocomposites also possess strong resistance to electric field failure and achieve significantly enhanced energy storage capability. With 3 vol% PUCNTs and 30 vol% CCTO, the breakdown strength of the nanocomposite can still be maintained at 125 kV mm −1 and the theoretical maximum energy density reaches to 15.5 J cm −3 , which is nearly 3 times compared to neat PVDF (5.1 J cm −3 ). These merits of the PUCNTs-CCTO/PVDF nanocomposites suggest that the strategy proposed herein is a promising avenue for the development of dielectric materials with high energy storage capacity.
研究领域:
材料科学
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纳米技术
·
聚合物科学
·
电介质
·
储能
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Liang Gao,Qianqian Xiao,Chengxi Wang,Jing Sun,Funing Zhang,Xuan Wang
In the realm of advanced electrical equipment and systems, polymer nanocomposites possess significant application value due to their excellent dielectric properties. Metal@ceramic fillers with a core-shell structure can enhance the dielectric constant ( ε ′) of polymer nanocomposites; however, their application is limited by the high dielectric loss (tan δ ). A magnetic field tailoring strategy is introduced in this article to significantly improve the dielectric properties of poly(vinylidene fluoride) (PVDF) composites. Magnetic CaCu 3 Ti 4 O 12 –Ni (CN) composite fibers are formed by embedding Ni nanoparticles within CaCu 3 Ti 4 O 12 (CCTO) fibers. Furthermore, the CN fibers are horizontally orientated in the PVDF matrix by tailoring the optimal magnetic field to 1.0 T–150 ℃. This results in a significant increase in the ε ′ of 25, which is 92 % and 194 % higher than that of a CN fiber without magnetic field treatment and pure PVDF, respectively, while maintaining a low tan δ of 0.08. Experimental and simulation results indicate that the magnetic orientation tailoring enhances the multi-interface polarization, especially the inner interfacial polarization (△ P in ) at the CCTO/Ni interfaces, dominantly improving dielectric performance, as evidenced by the high interfacial polarization strength, △ ε 2 ∼ 141.51, the low activation energy, E a ∼ 0.81 eV, and the large △ P in ∼ 1.06×10 4 μC/m 2 . This magnetic orientation tailoring strategy offers a new paradigm and significant guidance for the development of polymer dielectrics with exceptional dielectric properties.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
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