Scientific Reports
·
2015
·Vol. 5
·期 1
·1-10
·
IF 5.578
Yang Yang,He Jinliang,Wu Guangning,Hu Jun
Insulation performance of the dielectrics under extreme conditions always attracts widespread attention in electrical and electronic field. How to improve the high-temperature dielectric properties of insulation materials is one of the key issues in insulation system design of electrical devices. This paper studies the temperature-dependent corona resistance of polyimide (PI)/Al 2 O 3 nanocomposite films under high-frequency square-wave pulse conditions. Extended corona resistant lifetime under high-temperature conditions is experimentally observed in the 2 wt% nanocomposite samples. The “thermal stabilization effect” is proposed to explain this phenomenon which attributes to a new kind of trap band caused by nanoparticles. This effect brings about superior space charge characteristics and corona resistance under high temperature with certain nano-doping concentration. The proposed theory is experimentally demonstrated by space charge analysis and thermally stimulated current (TSC) tests. This discovered effect is of profound significance on improving high-temperature dielectric properties of nanocomposites towards various applications.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 20
·10950-10959
·
IF 14.511
Xue-Jie Liu,Ming-Sheng Zheng,Gang Wang,Yi-Yi Zhang,Zhi-Min Dang,George Chen,Jun-Wei Zha
Polymer dielectrics have been widely used in electrical energy storage devices. However, the relatively low operating temperature hinders their applications in harsh environments. Herein, the molecular structure of polyimide (PI) is optimized by adjusting the reaction kinetics of polyamic acid, which improves the energy storage performance of PI at elevated temperature. The PI film with an optimal imidization degree achieves a simultaneous increase in dielectric permittivity (εr) and breakdown strength (Eb), resulting in a maximum discharged energy density (Ue) of 6.9 J cm−3 with a charge–discharge efficiency of 90.0% at room temperature and a high Ue of 3.9 J cm−3 at 150 °C. The introduced –COOH/–CN–OH– polar groups increase the εr through the enhancement of dipole polarization. Moreover, an appropriate number of –COOH/–CN–OH– groups as deep traps reduce the mobility of carriers, thereby increasing the Eb. Finite element simulation reveals that PI with an appropriate imidization degree exhibits suppressed space charge accumulation and improved electric field distortion. This method reduces the PI processing temperature, which effectively reduces the production energy consumption. For verifying the universality of the design strategy, two other PIs prepared from different monomers are also demonstrated to have simultaneous improvement in εr and Eb.Finally, this production process of only reducing the preparation temperature without adjusting the original commercial PI production equipment is crucial for the practical application of capacitor films in the future.
研究领域:
材料科学
·
电气工程
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2023
·
IF 4
Huijian Ye,Mengyao Ping,Wenxian Liu,Lixin Xu
Polymer films with tailored dielectric properties and large electrical displacement are required for applications in microelectronics due to the need for ultrahigh speed and low transmission delays. In this study, we developed a low- k polyimide (PI) nanocomposite incorporated with metal–organic framework hollow ZIF-8 (HZIF-8) nanocrystals to achieve a high energy storage capacity. The PI nanocomposite film was prepared by solution casting a mixture of HZIF-8/polyamide acid with thermal imidization. A dielectric constant of 2.26 was obtained at 100 Hz for the 5 wt% nanocomposite with a multi-stage pore architecture. Due to improved interfacial polarization, the 1 wt% nanocomposite had a high energy density of 12.2 J/cm 3 and a charge–discharge efficiency of 70% at 600 MV/m. The PI nanocomposite film exhibited dielectric reliability with inherent flexible performance, and it is expected to be a primary candidate for polymer dielectric applications in microelectronics.
研究领域:
材料科学
·
微电子学
✓ 已验证
DOI
高影响因子
IONICS
·
2021
·Vol. 27
·期 4
·1579-1588
·
IF 2.817
Liu Zuyan,Yao Linxin,Hu Jiqing,Qiu Zhiming,Yan Yurong
A kind of fluorinated polyimide carrying sulfonyl groups (SFPI) as a novel binder is synthesized, which possesses excellent thermal stability, solubility, and mechanical properties. The cells with SFPI binder exhibit lower impedance and polarization compared with the cells adding the conventional PVDF binder. The electrochemical test results showed that the SFPI binder–based LiFePO 4 (LFP) electrode exhibits 134.1 mAh g −1 after 100 cycles and about 94.1% of the capacity is maintained. Especially, the overcharge safety of lithium-ion batteries during overcharge state is significantly improved by incorporating a SFPI binder.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
AICHE JOURNAL
·
2022
·Vol. 68
·期 8
·e17688
·
IF 4.167
Xi Chen,Guining Chen,Guozhen Liu,Gongping Liu,Wanqin Jin
Mixed-matrix membranes (MMMs), judiciously combining processability of polymer and remarkable separation performance of nanofillers, have been extensive pursuits for molecular separation process. Permeability matching between filler and polymer is one of the necessary requisites to desirable mixed-matrix effect. Considering the superior molecular sieving effect of UTSA-280 metal-organic frameworks on C 2 H 4 and C 2 H 6 , here, we report two types of UTSA-280/6FDA-polyimide MMMs toward C 2 H 4 /C 2 H 6 separation. The molecular sieving effect of UTSA-280 endowed 6FDA-DAM:DABA(3:2) membrane with simultaneous improvements in C 2 H 4 permeability and C 2 H 4 /C 2 H 6 selectivity. Optimally, when the filler reached 21.80 wt%, C 2 H 4 permeability and C 2 H 4 /C 2 H 6 selectivity was increased to 6.49 Barrer (by 15%) and 4.94 (by 32%), respectively. On the contrary, UTSA-280/6FDA-DAM MMMs showed undesirable mixed-matrix effect that C 2 H 4 permeability decreased meanwhile C 2 H 4 /C 2 H 6 selectivity nearly kept at polymeric pristine membrane level. It was found that permeability matching between two phases was responsible to these opposite mixed-matrix effects. More specifically, UTSA-280 had a relatively low gas permeability so that it required a less permeable polymeric matrix like 6FDA-DAM:DABA(3:2) to exert its molecular sieving effect. Furthermore, the optimal-matching 6FDA-matrix in permeability with UTSA-280 fillers was predicted by theoretical model. This work not only reports improving C 2 H 4 /C 2 H 6 separation performance via mixed-matrix formulation, but also emphasizes the importance of permeability matching between polymer and filler to realize the mixed-matrix effect.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2026
·
IF 14
Jv Li,Chunwang Xu,Hongmei Chen,Kejing Yu,Gang Liu,Fenghua Zhang,Wenbing Li
Designing flexible electromagnetic interference (EMI) shielding materials that transition from static shielding to dynamic adaptability remains a significant challenge in the development of next-generation electronic protection. In this study, we fabricated a reusable flexible polyimide (PI)/MXene/silver nanowires (AgNWs) (PMA) EMI shielding composite film by assembling MXene and AgNWs onto a shape-memory PI matrix using a vacuum-assisted filtration technique. When the ratio of MXene to AgNWs was 2:1, the composite film exhibited a maximum electrical conductivity of 132 S/cm and an EMI shielding effectiveness of 60.68 dB in the X-band (8.2-12.4 GHz). After further optimizing the material structure, the gradient-structured PMA composite film (G-PM 2 A 1 ) achieved a shielding effectiveness of 67.85 dB. The shielding performance remained essentially unchanged under harsh conditions, including ultrasonic cleaning, acid corrosion, high temperature (250 °C), and low temperature (−196 °C). Owing to the intrinsic shape-memory properties of polyimide, the film could recover its original structure after repeated deformation-heating cycles, maintaining an EMI shielding effectiveness above 60 dB. Moreover, the composite film exhibited excellent thermal stability, mechanical strength, and flame retardancy. Its lightweight, flexibility, and environmental stability indicate potential for localized EMI shielding applications relevant to electric vehicle battery systems, where lightweight, flexible, and environmentally robust shielding layers are required.
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS A-PHYSICAL
·
2026
·
IF 5.1
Fang Suo,Tao Wan,Fei Chang,Jianwei Cui,Yongtao Yao,Weijian Yuan,Xuelin Zhang,Yanju Liu
With the rapid development of aerospace engineering, geological exploration and intelligent fire protection, increasing attention has been directed toward sensing technologies for high temperature environments. In this case, flexible mechanical sensors still face challenges such as high temperature resistance and temperature drift. In this study, a novel biomimetic material was proposed to improve thermal resistance and solve the problem of high temperature drifting of sensors. Drawing inspiration from the structure of cuttlebone, a bioinspired anisotropic polyimide aerogel (BA-PA) using polyimide has been developed with bidirectional freezing method. The BA-PA exhibits excellent thermal stability and good fatigue resistance, making it an ideal dielectric layer for capacitive sensors. BA-PA sensor demonstrates stable force-electrical response and an ultrafast response time (∼10 ms). Meanwhile, the sensor operates stably with wide range from 20°C to 340 °C. Finally, the BA-PA sensor was demonstrated to possess the capability of achieving both tactile and gesture sensing. This work expands the application scope of polyimide aerogels and provides a new strategy for sensing under high-temperature environment.
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2026
·
IF 8.2
Zhuo Chen,Siyan Hu,Qing Liu,Zhixin Huang,Xiaohua He
The structural rigidity inherent to polyimide (PI) aerogels, derived from their aromatic backbones, leads to a challenge for tailoring flexibility. This study addresses this limitation through a deliberate dual–silicon strategy that synergistically modulates molecular and nanoscale architecture. By integrating amine–propyl–terminated polydimethylsiloxane (APPS) into the PI backbone and dispersing silica nanoparticles within the matrix, we construct a hybrid network where flexible APPS segments enhance chain mobility while rigid silica nanoparticles provide reinforcement. This organic–inorganic synergy, coupled with directional freezing, yields an aerogel that achieves an exceptional balance of flexibility and robustness, enabling efficient resilience across an extreme temperature range from –196 to 250 °C. The material further exhibits multifunctionality, including ultra–low density (∼19.6–25.7 mg·cm −3 ), outstanding thermal insulation (overall thermal conductivity of 32.7–38.3 mW·m −1 ·K −1 at 25 °C), excellent flame retardancy (the limiting oxygen index of 30.2%), and efficient oil absorption over a broad temperature range (adsorption capacity of 60.2-68.3 g/g for dichloromethane at 25 °C, 31.7–32.0 g/g for pump oil at 200 °C, and 30.0–35.2 g/g for colza oil at 200 °C). This work demonstrates a principled approach to designing high–performance PI aerogels with tunable mechanics for extreme–environment applications.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2026
·
IF 3.6
Tianshu Wang,Dongpeng Li,Dandan Li,Wei Wang,Youhai Yu,Guangtao Qian,Chunhai Chen
Incorporating functional groups capable of interacting with gas molecules into the molecular structure is a pivotal strategy for enhancing the performance of polymer-based gas separation membranes. In this study, two diamines featuring spiro-bis-indane moieties and distinct functional groups were separately polymerized with 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) to synthesize two polyimide membranes. The effects of hydroxyl ( OH) groups and phenylamino ( NHPh) groups on gas separation performance were systematically investigated. Hydroxyl groups are known to enhance CO 2 solubility via hydrogen-bond-like interactions while disrupting chain packing to increase free volume, synergistically improving separation efficiency. This work further demonstrates that the basic phenylamino groups selectively adsorb CO 2 through Lewis acid–base interactions, boosting CO 2 solubility and amplifying solubility differences with nonpolar gases. Additionally, the rigid spiro-bis-indane structure collaborates with these functional groups to tailor the microporous network, thereby optimizing gas transport properties. Graphical In this work, two diamine monomers containing two different polar groups (phenylamino group and hydroxyl group, respectively) were synthesized and then polymerized with 6FDA to prepare gas separation membranes. This study verifies the modification method applicable for carbon dioxide/nitrogen separation.
✓ 已验证
产品关联
DOI
高影响因子
POLYMER BULLETIN
·
2019
·Vol. 77
·期 11
·5899-5912
·
IF 1.858
Li Jianwei,Yu Ni,Jing Zhanxin,He Xinhai,Shi Xuetao,Zhang Guangcheng
This work provides a method for fabricating rigid polyimide foams via thermal foaming method of nadimide-end-capped polyester-amine oligomer (NPEAO) precursor particles, which were synthesized by reaction of benzophenone-3,3′,4,4′-tetracarboxylic dianhydride and cis -5-norbornene-endo-2,3-dicarboxylic anhydride (NA) with different diamines. The foaming mechanism of the rigid PI foams was systematically investigated. The experiment demonstrates that the pre-treatment of the NPEAO precursor particles and foaming temperature are two pivotal factors that determine the foaming processes. The densities of the prepared rigid PI foams are mainly in the range of 40–200 kg m −3 . Moreover, the density and morphology of the PI foams can be effectively controlled by adjusting these two factors. Besides, the obtained rigid PI foams present excellent mechanical and thermal properties, specifically, the flexural and compressive strength reaches as high as to 1.42 MPa and 0.47 MPa, respectively, with the density of 0.076 g cm −3 , which are superior to common PI foams and aerogels that of reported in the literature. Therefore, these superior mechanical and thermal properties make obtained rigid PI foams promising candidates as structural materials in the advanced manufacturing industry.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2018
·Vol. 18
·期 5
·3291-3298
·
IF 1.354
Yang Xi,Yu Xiaoyan,Naito Kimiyoshi,Ding Huili,Qu Xiongwei,Zhang Qingxin
A new thermally conductive and electrically insulative polyimide were prepared by filling different amounts of hexagonal boron nitride (h-BN) particles, and the thermal conductivity of Polyimide (PI) composites were improved with the increasing h-BN content. Based on this,
two methods were applied to improve thermal conductivity furtherly at limited filler loading in this paper. One is modifying the h-BN to improve interface interaction, another is fabricating a nano-micro hybrid filler with 2-D h-BN and 0-D nano-scale nanodiamond (ND) to build
more effective conductive network. Both surface modification and hybrid system have a positive effect on thermal conductivity. The composites introducing 40 wt% hybrid filler (the weight ratio of ND/modified BN was 1/10) showed the highest thermal conductivity, being up to 0.98 W/(m K) (5.2
times that of PI). In addition, the composites exhibits excellent electrical insulation, thermal stability properties etc.
研究领域:
材料科学
·
聚合物复合材料
·
热管理材料
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Bo Peng,Pengbo Wang,Hang Luo,Yang Xiao,Haoran Xie,Guanghu He,Deng Hu,Dou Zhang
The commercial high-temperature dielectric aromatic polyetherimide (PEI), due to the electron conjugation between aromatic rings in molecular chains, causing an exponential increase in conduction loss, which results in a sharp decline in capacitive performance at elevated temperatures and electric fields. Here, an all-organic dielectric based on molecular isolation strategy is proposed, attempting to suppress the conduction loss and improve the high-temperature capacitive performance of PEI by introducing the cyclodextrin (CD) with large ring-like structure and amounts of hydroxyl groups. The addition of CD expands the interchain spacing of PEI, interrupts the electron conjugation of aromatic rings and hinders the formation of electronic channels between molecular chains. As results, CD/PEI composites show enhanced breakdown strength ( E b ) (increased by 24 %) and suppressed leakage current (reduced by 220 %), with much lower energy loss than that of pure PEI. The 1.5 wt% CD/PEI all-organic composite achieves an energy storage density ( U e ) of 5.12 J cm −3 with charge-discharge efficiencies ( η ) > 90 %. It achieves stable cyclability over 100,000 cycles at 150 °C compared with 4217 cycles of pure PEI. This work offers an innovative strategy for the fabrication of all-organic composite dielectrics with high U e and η simultaneously at harsh environment.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）