COMPOSITES PART B-ENGINEERING
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2021
·
IF 9.078
Jundong Zhu,Fuxing Zhao,Tangping Peng,Hao Liu,Le Xie,Chongwen Jiang
Advanced composite aerogel materials have attracted much attention due to the unique structure and properties. However, the efficient manufacturing process and structural stability were still a challenge. Herein, a novel hydroxyapatite nanowires/polyimide (HAnws/PI) composite aerogel was synthesized by the ultralong HAnws combined with polyamic acid via directional freezing and thermal imidization. Among them, the HAnws and PI intertwined to form a three-dimensional network structure, which decreased the volume shrinkage of aerogel in thermal imidization from 42.9% to 12.6%, resulting in high porosity (>96%) and low density (0.0329–0.0431 g cm −3 ). In addition, the HAnws/PI aerogel with layered porous structure exhibits obvious anisotropic mechanical properties. The axial specific modulus as high as 78.05 kN m kg −1 and radial high elasticity can withstand 100 cycles of fatigue resistance . Moreover, the lowest radial thermal conductivity at 32.21 mW m −1 K −1 and the maximum of the anisotropy factor was 2.2, which was very suitable for insulation pipes to prevent additional heat loss. Therefore, the novel nanofibers reinforced organic aerogel was expected to provide more abundant functional applications in energy efficiency.
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-10
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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.
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TRIBOLOGY LETTERS
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2017
·Vol. 66
·期 1
·1-18
·
IF 1.891
Xin Yuanshi,Xu Fanglin,Wang Mingming,Li Tongsheng
Modified carbon nanotube/nano-MoS 2 (CMS) hybrid as a self-lubricating and anti-wear nanofiller was prepared through chemical compounding and then incorporated into polyimide (PI) matrix to yield CMS/PI composite by in situ polymerization. For comparison, carbon nanotube (CNT), nano-MoS 2 as well as the mixture of them (CNT-MoS 2 ) were also incorporated into PI matrix separately to evaluate the superior performance of CMS hybrid. Morphology, mechanical capacity and tribological behavior of the as-prepared nanocomposites were investigated, and the discrepancies on the above-mentioned properties caused by the different structures between CMS hybrid and CNT-MoS 2 mixture were discussed in detail. With only 0.5 wt% addition of CMS, the friction coefficient and wear rate of CMS/PI composite decreased by 31 and 84%, respectively, compared to virgin PI. The results showed that the combinational structure of CMS hybrid, as CNT-coated few-layer MoS 2 nanosheet, which took the advantage of both CNT and nano-MoS 2 , contributed to the synergistic effect on the tribological properties.
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POLYMER INTERNATIONAL
·
2011
·Vol. 61
·期 1
·111-117
·
IF 2.056
Bing Fang,Kai Pan,Qinghan Meng,Bing Cao
This study investigated the preparation of polyimide solvent-resistant nanofiltration membranes by a two-step method (casting the membrane first and then crosslinking by the thermal imidization method). The influences of polymer concentration, thickness of membranes, temperature of the imidization, phase inversion time and thermal imidization procedure were studied. The membranes with the highest rejection rate of Fast Green FCF (molecular weight 808.86 g mol −1 ) were prepared in the following conditions: polymer concentration 13 wt%, phase inversion time 1 h, membrane thickness 150 µm and thermal imidization procedure 200 °C for 2.5 h, 250 °C for 2 h and 300 °C for 2 h in a vacuum environment; the heating rate was 5 °C min −1 . The membrane was stable in most of the solvents tested and the fluxes of some common solvents were equal to or higher than a number of commercial solvent-resistant nanofiltration membranes. A much higher rejection of dyes in water than in methanol was observed in the filtration experiments and a new way to explain it was developed. Copyright © 2011 Society of Chemical Industry
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NANOTECHNOLOGY
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2022
·Vol. 34
·期 10
·105203
·
IF 3.953
Peng-Fei Qian,Jing-Qi Wang,Tao Wang,Xuguo Huai,Wen-Hao Geng,Qiangxia Zhu,Ying Tian,Li-Chao Jing,Ze-Long Bao,Hong-Zhang Geng
Transparent conductive films with high stability were prepared by embedding silver nanowires in colorless polyimide and adding a protective layer of exfoliated graphene. The films exhibit great light transmission and conductivity with a sheet resistance of 22 Ω sq−1 at transmittance of 83%. Due to its special embedded structure, the conductive layer can withstand several peeling experiments without falling off. In addition, the most outstanding advantage is the ultra-high stability of the films, including high mechanical robustness, strong chemical corrosion resistance and high operating voltage capacity. The organic light-emitting diode devices prepared based on this transparent conductive electrode exhibit comparable efficiency to indium tin oxide (ITO) based devices, with C.E.max = 2.78 cd A−1, P−1.E.max = 1.89 lm W−1, EQEmax = 0.89%. Moreover, the efficiencies were even higher than that of ITO devices when the operating voltage of the device exceeds 5 V. The above performances show that the transparent conductive electrode based on this structure has high potential for application in organic electronic devices.
研究领域:
材料科学
·
电子工程
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Journal of Energy Storage
·
2022
·
IF 8.907
Yurui Deng,Yuelei Pan,Caihong Li,Zhongxin Zhang,Lunlun Gong,Yangyang Fu,Long Shi,Heping Zhang,Xudong Cheng
Separator is an important component in lithium-ion batteries, and it plays a critical role in ensuring the overall thermal safety and electrochemical performance of a battery . To date, the development of safe and robust lithium-ion batteries is still hindered by the commercial polyolefin membrane due to its poor thermal stability and inferior electrolyte wettability . Thus, to address this shortcoming, an advanced polyimide aerogel separator was designed by simple one-pot reaction via co-precursor and cross-linking methods in this work. Based on molecular structure designation and gelation time control, the as-prepared polyimide aerogel separator (C-PI separator) possessed high porosity, good flexibility, excellent thermal stability, and superior electrolyte wettability, which are essential attributes of a high-performing separator. LiFePO 4 |Li metal battery was later assembled with C-PI separator, and the cell demonstrated outstanding long-term cyclic performance (>1000 cycles at 1C with 93.6 % retention). Compared with PE separators, the NCM523-graphite pouch cell assembled with C-PI separators exhibited high thermal stability with a higher thermal runaway temperature (204.9 °C vs. 140.4 °C) and a lower maximum temperature rise (0.06 °C/min vs. 8 °C/min), demonstrating its application potential in scenarios with high requirements for safety. Furtherly, the thermal runaway mechanisms of the full cells were explored and explained in this work.
研究领域:
材料科学
·
能源技术
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HIGH PERFORMANCE POLYMERS
·
2024
·
IF 1.8
Guohao Zhu,Jilei Xu,Huimin Sun,Ping Chen
A novel phenylethynyl-terminated siloxane-containing ortho-hydroxy polyimide (O-SPI) was synthesized and physically blended with thermoplastic polyimide (PI) to enhance both the thermal and mechanical properties of polyimide, addressing the growing demand for high-performance materials in harsh environments. The blend underwent conversion to semi-Interpenetrating Polymer Networks (semi-IPNs) and benzoxazole structures through thermal curing of reactive phenylethynyl groups and thermal rearrangement of ortho-hydroxy imide units. The trends in thermal and mechanical properties were investigated in relation to the chemical structures and varying mass fraction of O-SPI. The covalent incorporation of semi-IPNs and rigid benzoxazole structures restrict segmental motion while the backbone linkage confers the toughness of the blends. These synergistic effects insure the cured blends with high glass transition temperatures (472.51°C) and tensile strength (117.81 MPa) simultaneously, demonstrating their potential for applications in challenging conditions.
研究领域:
材料科学
·
高分子化学
·
工程
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ACS Applied Polymer Materials
·
2026
·
IF 5.2
Chenyi Yang,Yongcun Zhou,Xueqin Wang,Yang Zhou
Driven by the miniaturization and integration of electronic components, escalating thermal loads have necessitated the development of materials with high thermal conductivity. However, the direct incorporation of thermally conductive fillers (e.g., carbon nanotubes, CNTs) into polymer matrices often resulted in poor dispersion and interfacial compatibility, thereby limiting overall performance. In this study, a biobased polyimide (Bio-PI) was synthesized from 2,5-furandicarbonyl dichloride (FDCA-Cl2), a biobased FDCA derivative. Carboxyl-functionalized CNTs (c-CNTs) were engineered via SiO2 core–shell encapsulation and ODA modification to obtain surface-functionalized m-CNTs. During composite formation, in situ encapsulation of m-CNTs by the Bio-PI matrix generated self-assembled microcapsule architectures, enhancing filler dispersion and interfacial compatibility to establish stable thermal networks. At 30 wt % loading, PI/m-CNTs-30% achieved a thermal conductivity of 2.00 W/mK, representing an 11.76-fold enhancement over neat Bio-PI (0.17 W/mK). Concurrently, the SiO2 shell maintained balanced dielectric properties (εr = 6.53, tan δ = 0.026 at 1 MHz) and electrical resistivity (7.95 × 1012 Ω·cm). This composite demonstrates significant potential as a heat-dissipating material for electronic devices, particularly in advanced packaging requiring stringent dielectric and insulating performance. This work presents a methodology for fabricating high-performance renewable thermal management materials.
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Nano Materials Science
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2026
·
IF 20.5
Xin Li,Jing-hui Yang,Wen-jin Hu,Long-fei Tian,Nan Zhang,Yong Wang
High-temperature polyimide (PI) dielectrics with high energy density are urgently needed for capacitive energy storage fields. However, the breakdown strength ( E b ) and energy storage ( U e ) capabilities significantly deteriorate due to large conduction losses at high temperatures, limiting the practical applications of PI dielectrics. To address this issue, carbonized polymer dots (CPDs) with tunable band gaps were introduced into PI to prepare CPDs/PI composites. CPDs can also form physical entanglement and chemical crosslinking with PI molecular chains. Moreover, the wide band gap CPDs provide the composites with a higher energy barrier at the electrode/composite interface, effectively inhibiting the charge injection. Additionally, longer alkyl chains on the surface of CPDs are more conducive to their entanglement with PI molecular chains, which facilitates the formation of charge traps. Among the composites, the 12CPDs exhibit the largest band gap and longest alkyl chains. As a result, at a high temperature of 150 °C, the 12CPDs/PI0.2% film exhibits an exceptional U e of 4.0 J cm −3 , which is 2.47 J cm −3 higher than that of pristine PI with a U e of 1.53 J cm −3 , respectively.
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MICROCHEMICAL JOURNAL
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2026
·
IF 5.2
Jiaqi Geng,Xiaoyang Yu,Zhitan Huang,Faman Lin,Brij Mohan,Yanxin Lv,Wei Sun
Chloramphenicol (CAP) is a broad-spectrum antibiotic whose overuse poses environmental and public health risks, making rapid detection crucial. This study introduced a nanocomposite of CeO 2 , SiO 2 , and MoC nanoparticles in situ embedded in laser-induced graphene (CeO 2 -SiO 2 -MoC-LIG). The nanocomposite was synthesized via a laser-induced method using a polyoxometalate-based metal-organic compound and a polyimide mixture, and was further characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller analysis. The incorporation of nanoparticles significantly improved the conductivity, electrochemical response, specific surface area, and the number of active sites at the LIG electrode interface. Under optimal conditions, the CeO 2 -SiO 2 -MoC-LIG electrode enabled detection of CAP via linear sweep voltammetry, achieving a wide detection range of 0.1 μM–1.0 mM and a low limit of detection of 33 nM. The electrode also exhibited excellent selectivity against common antibiotics (peak current changes <12.1% at five-fold concentrations of interferents) and good stability (retaining 95.6% of the initial response after 9 days). Furthermore, this flexible electrode was successfully applied to monitor CAP in tap water and pork samples with satisfactory recoveries (96.3%–102.8%) and relative standard deviations below 3.34%, presenting a novel approach to designing flexible electrochemical devices.
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ACTA PHYSICO-CHIMICA SINICA
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2026
·
IF 13.5
Bo Liang,Yuyijian Zhao,Siyu Wang,Shihan Huang,Fangke Zhou,Chuankun Zhang,Yue Wang,Xiaoming Guo
Herein, a novel strategy for fabricating microwave absorption materials via molecular-level design that synergistically regulates dielectric and magnetic losses. The method utilizes a polyimide precursor containing both carboxyl and benzimidazole functional groups as the key component. Through an ice-templating process followed by in-situ ion exchange, Ni 2+ ions are uniformly incorporated into the polymeric skeleton. Subsequent thermal imidization and carbonization yield nitrogen-doped two-dimensional carbon nanosheets embedded with uniformly dispersed Ni/NiO nanoparticles (BPCN@Ni/NiO). This material exhibits significantly superior microwave absorption properties compared to its counterpart synthesized without the benzimidazole structure (NPCN@Ni/NiO). BPCN@Ni/NiO achieves a remarkable minimum reflection loss ( RL min ) of −69.02 dB with effective absorption bandwidth ( EAB ) of 8.92 GHz (8.28–17.2 GHz). Microstructural analyses confirm its three-dimensional interconnected nanosheet architecture, highly dispersed Ni/NiO species, and homogeneous elemental distribution. The performance enhancement is attributed to the synergistic complexation of Ni 2+ ions by benzimidazole and carboxyl groups, which enables efficient loading and uniform dispersion of nickel species, thereby optimizing impedance matching. Furthermore, the unique 2D conductive network, abundant heterogeneous interfaces (C/Ni/NiO), defect-induced dipole polarization, and magnetic coupling between Ni and NiO collectively contribute to synergistic multiple loss mechanisms, ultimately endowing the material with excellent microwave attenuation capability. This work offers a new pathway for designing lightweight, efficient, and broadband carbon-based composite absorbers through precise molecular engineering.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2026
·
IF 9.1
Ke Chen,Ruishan Li,Chengming Xiao,Xin Guo,Junwen Qi,Jiansheng Li
Efficient gas separation is essential for sustainable energy generation and industrial applications; however, membrane materials often encounter an intrinsic trade-off between permeability and selectivity. In this work, we overcome this limitation by incorporating phenolate-based metal-organic frameworks (termed as SU-102) into polyimides (6FDA-Durene) via a physical blending method. Attributable to the strong CO 2 affinity, significant porosity, and distinctive pore size of SU-102, the resulting mixed matrix membranes (MMMs) demonstrate a synergistic enhancement in both CO 2 permeability and selectivity. Specifically, MMMs with 30 wt% SU-102 amounts achieved a CO 2 /CH 4 selectivity of 33.6 and a CO 2 permeability of 1572.3 Barrer, representing increases by 1.8 and 2.2 times, respectively, compared to the pristine 6FDA-Durene membranes. Furthermore, the MMMs exhibited remarkable long-term stability over 72 h of continuous operation. Importantly, hydrogen-bonding interactions between the carboxyl and hydroxyl groups on SU-102 and the imide groups on 6FDA-Durene significantly enhanced the plasticization resistance of the MMMs, which withstood CO 2 pressures up to 12 bar. This work provides a feasible strategy for the design of high-performance gas separation membranes for practical applications.
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