COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Dongxu Liu,Hongtao Chi,Chuanguo Ma,Muyuan Song,Ping Zhang,Peibang Dai
To develop high-performance thermal management materials, herein, the hybrid nanoparticle (GF) of reduced graphene oxide and magnetic needle-like ferro oxide was successfully prepared by in-situ modification of polydopamine. A moving magnetic field induction (MF) strategy with a potential of large-scale application was proposed to realize the alignment of the GF in the boron nitride (BN)/polyimide composite film . The GF nanoparticles were partially aligned at a certain angle from in-plane direction of the composite film and synergistically improved the thermal conductivity network with the BN, which results in simultaneous enhancement in the in-plane and out-of-plane thermal conductivity. At 30 wt% filler content , the in-plane and out-of-plane thermal conductivity of the composite film reached 2.532 W m −1 K −1 and 0.425 W m −1 K −1 , which is 1233% and 150% higher than that of the pure PI, respectively. This work developed a novel and efficient approach for the design of high thermal conductive materials .
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高影响因子
POLYMER
·
2026
·
IF 5.1
Jiaxin Liu,Guan Wang,Li Zhang,Qikun Yang,Mingze Ou
KH550 modification improves Si3N4 dispersion and interfacial compatibility in PI. • KH550-modified PI/Si3N4 films exhibit low dielectric loss under high-frequency stress. • Corona aging lifetime reaches 31.5 min, 150% higher than that of pure PI. • MD reveals reduced free volume and enhanced interfacial charge trapping. Polyimide (PI), used as an insulation material for high frequency power transformers, tends to age as insulation due to partial discharge (PD). This study incorporates KH550 modified nanoscale silicon nitride (Si 3 N 4 ) into polyimide and prepares composite films via in situ polymerization. By combining experiments with molecular dynamics (MD) simulations, we study the dielectric performance and high frequency insulation properties of the modified films. First, FTIR and SEM analysis of the modified Si 3 N 4 particles and the composite films (before and after modification) shows that KH550 modification improves particle dispersion and interfacial compatibility in the matrix. Subsequently, the effects of KH550 modification and particle loading on film properties are examined. The results show that the dielectric constant and the dielectric loss of the modified films are lower than those of the unmodified films. In experiments, the high frequency dielectric loss of the modified films remains below 0.01. The introduction of modified Si 3 N 4 reduces local discharge activity in the film and effectively improves corona resistance lifetime, with the improvement increasing as the loading increases, reaching up to a 137% enhancement compared with the unmodified sample. Finally, MD simulations are used to explain the mechanism by which KH550 modification enhances PI performance. The results indicate that KH550 modification creates regions of low electrostatic potential on the Si 3 N 4 surface, enhancing the trapping of charge carriers and reducing interfacial polarization, while at the same time promoting aggregation of PI chains around the particles, reducing free volume and reducing potential breakdown pathways. Download: Download high-res image (609KB) Download: Download full-size image
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2026
·
IF 9.1
Shibo Zhao,Xinjun Wen,Hongge Jia,Mingyu Zhang,Yanqing Qu,Chengbao Geng
The continuous increase in greenhouse gas emissions is having a significant impact on the global climate system. To address this issue, efforts worldwide are promoting the development of clean energy source, with methane-rich biogas being a primary focus. However, the dilution of biogas with CO₂ significantly reduces its calorific value. Therefore, efficient methane purification and resource utilization are urgently required. This study specifically developed a high-efficiency gas separation membrane suitable for large-scale industrial applications. By precisely separating CO₂ from biogas, it provides crucial technological support for enhancing biogas energy quality and promoting its industrialization. Specifically, using a conventional polyimide membrane (6FDA-APAF) as the template, a series of intrinsically microporous polyimide membranes (PIM-PI membranes) were innovatively synthesized by incorporating fluorene-containing microporous units—Namely, 9,9′-bis(4-aminophenyl)fluorene (FDA) or 9,9′-bis(4-amino-3-fluorophenyl)fluorene (FFDA). Subsequent thermal rearrangement (TR) treatment produced PIM-PI(TR) membranes. Both the introduction of fluorene groups and TR treatment increased the interchain spacing of the membranes, with the thermally rearranged PIM-PI(TR) membranes exhibiting larger d-spacings and broader micropore peaks. The 6FDA-FFDA (PIM-PI membrane) achieved a CO₂ permeability coefficient of 151.87 barrer, which is 9.9 times higher than that of the nonporous conventional polyimide membrane (6FDA-APAF, 15.4 barrer). The 6FDA-APAF/FDA (8,2) TR400 [PIM-PI(TR) membrane], subjected to thermal rearrangement, further increased its CO₂ permeability coefficient to 813.80 barrer, representing a 19-fold improvement over the untreated membrane. Simultaneously, this membrane exhibited a CO₂/CH₄ permeability selectivity factor as high as 39.03, surpassing the 2019 Robeson upper bound. Furthermore, both macro- and micro-characterizations reveal structurally uniform and intact membranes. With superior fabrication quality that lays a solid foundation for industrial applications. These results highlight the promising potential of TR-treated PIM-PI (TR) membranes containing fluorene-based pore-forming units for gas separation. This study also offers essential technical support for the industrial application of polyimide membranes in biogas purification
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高影响因子
COMPOSITE INTERFACES
·
2025
·
IF 2.4
Zhenyu Zhang,Tao Li,Xiaohui Ning,Ping Yu,Rimika Sachdeva,Lin Bao,Yan Li
To overcome the low thermal stability of conventional polymers and the low elasticity of reduced graphene oxide (rGO) as oil-water separation materials, in this study, hierarchical porous polyimide/reduced graphene oxide (PI/rGO) sponges were prepared with SiO2, polyurethane (PU), polyether amine (PEA), and liquid paraffin (LP) templates, respectively. According to experimental results, all four types of PI/rGO exhibit ideal elasticity, wherein the PI/rGO (SiO2), PI/rGO (PEA), and PI/rGO (LP) further exhibit high thermostability and excellent adsorption capability in oil and organic solvents. This study proposed a new strategy to synthesize an oil-separation material with a balanced performance of thermal stability, elasticity, and oil-adsorption.
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高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Weiya Chen,Yanbo Liu,Ying Ma,Wenxiu Yang
Functionalized TiO 2 (f-TiO 2 ) was synthesized by the atom transfer radical polymerization process and then three types of composite nanofiber membranes including PI/PVdF-HFP (PI/PH, with no nanoparticles contained in PI), TiO 2 @PI/PVdF-HFP (T@PI/PH, with TiO 2 mixed in PI) and f-TiO 2 @PI/PVdF-HFP (f-T@PI/PH, with f-TiO 2 blended in PI) were prepared by bicomponent co-electrospinning technique which could separately maintain the original properties of both PVdF-HFP and PI nanofibers. UV–vis characterization manifested that the modified nanoparticles can provide significant improvements in reducing the particle agglomeration . Morphology, porosity, electrolyte uptake and liquid electrolyte contact angle of all the electrospun separators were investigated, and results showed that the composite separator with 2% f-TiO 2 nanoparticle had smaller fiber diameter , higher porosity, larger electrolyte uptake, smaller contact angle and more excellent thermal dimensional stability. More importantly, the tensile strength of all the composite membranes increased by more than three times after thermal calendering process, which resulted from the several bonded points caused by the fusion of PVdF-HFP component with low melting temperature. Additionally, electrochemical properties of PI/PH, 2% T@PI/PH and 2% f-T@PI/PH composite separators and cycling performances of corresponding batteries were evaluated and 2% f-T@PI/PH composite separator showed better properties than the other two.
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高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Wentao Chen,Ke Zhang,Shuai Wang,Chunhai Chen,Xiaogang Zhao,Hongwei Zhou,Daming Wang
The application of polyimide (PI) as an effective sizing agent for carbon fiber (CF) in CF/poly ether ether ketone (PEEK) composites represents a promising approach. Here, a series of novel carboxylated waterborne PI sizing agents with different aliphatic ratios were designed to construct a rigid-flexible gradient interphase for the purpose of promoting interfacial adhesion between CF and PEEK. It was observed that the mechanical properties of the composites were optimal when the molar ratio of rigid diamine monomer to flexible diamine monomer reached 7:3. Significant augmentation was observed in various mechanical and interfacial properties, including tensile modulus (25.6 %), tensile strength (19.8 %), flexural modulus (28.5 %), flexural strength (15.8 %), impact strength (24.3 %), and IFSS (57.8 %). Furthermore, the tensile strength of the composites exhibited a greater increase (27.2 %) at elevated temperatures, thus indicating that the role of the interfacial layer was more pronounced at high temperatures. The interphase was analyzed by peak force quantitative nanomechanical imaging (PF-QNM) mode of atomic force microscopy (AFM), the results indicated the formation of a modulus transition zone between the CF and PEEK. This zone exhibited a gradient change of modulus, enabling the composite to transfer and distribute applied loads more effectively when subjected to external forces. Consequently, the findings of this study demonstrated the potential of waterborne PI sizing agents for application on CF, offering a promising avenue for surface modification of high-performance CF/PEEK composites.
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高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2024
·
IF 8.3
Dongya Guo,Binzhe Tan,Xiaojie Jiang,Guangyu Gao,Yu Lin
With the demand for further miniaturization and higher frequency operation of electronic devices, polymer films with high thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) are urgently required. Herein, polyimide (PI)/boron nitride nanosheets (BNNS) aerogels with oriented porous structure are fabricated by unidirectional-freezing and freeze-drying methods. Subsequently, hierarchical PI/BNNS/Ti 3 C 2 T x composite films with consecutively electrically and thermally conductive networks are successfully prepared via a unidirectional PI/BNNS aerogels-assisted immersion and hot-pressing strategy. Owing to the three-dimensional conductive dual networks of BNNS and Ti 3 C 2 T x , the composite film exhibits excellent thermal conductivity with the maximum in-plane value of 4.73 W/(m·K), increased by 456 % compared to pure PI film. Moreover, the conductive network of Ti 3 C 2 T x is conducive to the excellent EMI shielding performance, endowing the PI/BNNS/Ti 3 C 2 T x composite film with an outstanding EMI SE value of 49.2 dB at 8.2 GHz with a low MXene content of 6 wt% and thickness of 300 μm. Furthermore, the composite film shows the superior Joule heating performance with fast thermal response and sufficient reliability. Therefore, the resulting composite film exhibits excellent thermal conductive, EMI shielding and Joule heating performance, which enables the potential application of multifunctional composites for thermal management and EMI shielding.
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高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Jilin Wang,Wenzhuo Chen,Yuchun Ji,Yuanlie Yu,Yuetong Wu,Jialong Shen,Huasong Liang,Guoyuan Zheng,Huanping Zhou,Fei Long
Heat dissipation has become a bottleneck restricting large-scale integration and flexible electronic technologies. This study reports a novel fabrication strategy to prepare flexible stachytarpheta jamaicensis flower-like hexagonal boron nitride nanoribbons (SJF-BNNBs) and their composite films with polyimide (PI). The effect of synthesis conditions on the morphology of SJF-BNNBs was investigated, and the growth mechanism was proposed. The in-plane and through plane thermal conductivities of the 4 wt% SJF-BNNBs/PI composite film reach 5.98 W m −1 K −1 and 0.79 W m −1 K −1 , which are 3047 % and 316 % higher than those of the pure PI film, respectively. The in-plane and through plane thermal conduction enhancement efficiencies reach 761.8 % and 78.9 %, respectively. The tensile strength of the composite film is 61.7 % higher than that of pure PI, and maintains excellent electrical insulating and thermal stability properties. Infrared imaging tests verified the excellent heat dissipation performance of the composite film as a thermal interface material and a flexible copper clad laminate substrate, where the operating temperature of device could be reduced by 17.3 °C. To the best of our knowledge, SJF-BNNBs outperform the most efficient thermally conductive electrically insulating filler and are to break the overcome of polymer composites in heat dissipation applications.
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高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Yanqing Cong,Xinyue Li,Shiyi Zhang,Qiuang Zheng,Yi Zhang,Shi-Wen Lv
Photocatalytic technique is regarded as the cleanest approach for producing H2O2. Herein, two kinds of novel polyimide COFs decorated with CQDs (namely, MPa-COFs/CQDs and MNd-COFs/CQDs) were constructed by using the one-pot hydrothermal method. Due to the electron donor role of CQDs, the recombination of photoinduced electrons and holes was suppressed after the combination of polyimide COFs with CQDs. Importantly, the introduction of CQDs not only boosted the absorbing ability of polyimide COFs toward visible light but also reduced the impedance and improved the charge transfer efficiency. After CQDs were embedded into polyimide COFs, the surface hydrophilicity of catalysts was significantly improved, which provided convenience for the water oxidation reaction. Benefiting from the electron donor–acceptor interaction between polyimide COFs and CQDs, a step-by-step two-electron oxygen reduction reaction over polyimide COFs was enhanced. More interestingly, the embedding of CQDs can create a direct two-electron water oxidation reaction pathway, which played an important role in photocatalytic H2O2 generation. Meanwhile, H+ generated from water oxidation can also be used for the reduction of oxygen to form H2O2. Under the synergistic effects of water oxidation and oxygen reduction, as-prepared MPa-COFs/CQDs-2 displayed excellent performance in photocatalytic H2O2 generation, and its yield was as high as 540 μmol/g within 60 min. In short, the current work shared an effective strategy to improve the performance of polyimide COFs in photocatalytic H2O2 production.
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PubMed
高影响因子
POLYMER
·
2021
·
IF 4.43
Chunhong Zhang,Qingtao Lv,Yanjian Liu,Chao Wang,Qiang Wang,Hao Wei,Lijia Liu,Junqing Li,Hongxing Dong
In this paper, porous polyimide composites (PPIC) for electromagnetic interference (EMI) shielding were rationally designed and fabricated by using polyimide (PI) matrix, polyaniline modified graphene oxide (PANI-g-GO) and multiwalled carbon nanotube (MWCNT) as hybrid fillers through innovatively combining in-situ polymerization process and thermally assisted non-solvent induced phase separation (TNIPS) method. The polyimide matrix and porous structure endow the composites with good heat resistance and lightweight, and hybrid fillers can form effective conductive networks in the PI matrix, which results in the enhancement of EMI shielding performance. The porous polyimide composite with a hybrid filler content of 12 wt% (PPIC12) exhibited a low density of 0.56 g/cm 3 , high T 10 of 554.81 °C, excellent EMI shielding effectiveness up to 28.2 dB at a thickness of 2 mm. Therefore, the novel porous polyimide composites are promising polymer-based EMI shielding materials with lightweight and good heat resistance.
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高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 18
·10005-10012
·
IF 7.443
Xinliang Fang,Xiaoyun Liu,Zhong-Kai Cui,Jun Qian,Jijia Pan,Xinxin Li,Qixin Zhuang
This study proposes a novel and facile method to synthesize high-quality NH2-functionalized and carboxyl-functionalized graphene oxide (PPD–CFGO)/polyimide (PI) composite films with high dielectric constant (ε), low dielectric loss, high-temperature resistance and outstanding mechanical properties by in situ polymerization. In addition to the partial carboxyl groups located at the edges, the ample hydroxyl and epoxy groups bonded on the basal plane of graphene sheets were exploited to covalently bond to the amines. GO was modified by oxalic acid to obtain carboxyl-functionalized GO (CFGO) before amidation. NH2-functionalized CFGO (PPD–CFGO), dispersing well in dimethylacetamide (DMAc), was the initial platform for polymer grafting to improve the CFGO dispersion in the polymer matrix. Partially reduced graphene nanosheets are formed during the imidization process. The PPD–CFGO/PI composite films exhibit high tensile strength (up to 848 MPa) and Young's modulus (18.5 GPa). The thermogravimetric analysis results indicate that the PPD–CFGO/PI composites have good thermal stability below 500 °C. The dielectric constant increases up to 36.9 with an increasing amount of PPD–CFGO, higher than that of the pure PI polymer by a factor of 12.5, while the dielectric loss is only 0.0075 and the breakdown strength still remains at a high level (132.5 ± 9.3 MV m−1).
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高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Long Ni,Hang Ye,Yuanyu Chang,Ke Yang,Yinfu Luo,Liwei Yan,Shuang Xia,Mei Liang,Shengtai Zhou,Huawei Zou
A series of silica aerogel (SiA)-containing copolymerized polyimide composite foams were prepared by combining microwave-assisted foaming with vacuum/ultrasound-assisted impregnation and freeze-drying methods. The fluorinated polyimide foams (F-PIF) featuring “bottom-up” directional growth of pores and uniform impregnation with polyimide aerogels containing fluorine and silicon moieties (FSi-PIA) and nano SiA, exhibited enhanced mechanical and thermal insulation performance as well as hydrophobicity. The relationship and mechanism between copolymerized molecular chain structure, anisotropic pore structure, and properties of composite foams were elucidated. The F-PIF/FSi-PIA/SiA composite foams showed mechanical robustness in the vertical direction (compressive strength improvement of 157.8%) and mechanical flexibility in the horizontal direction (compression response rate up to 97.9%). In addition, the prepared composite foams showed extraordinary hydrothermal aging resistance, thermal stability and thermal mechanical properties, self-extinguishing flame retardancy, and high-temperature thermal insulation with thermal conductivity ranging from 0.0251 to 0.0555 W/(m·K) between 25 and 300 °C. Benefiting from the unique anisotropic pore structure, the impregnation of FSi-PIA as well as nano SiA endowed F-PIF/FSi-PIA/SiA composite foams with a water contact angle as high as 151.1° and water absorption rate as low as 0.31 g/g. Therefore, a facile strategy was proposed to fabricate multifunctional PI composite foams that exhibit promising applications in extreme environments.
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高影响因子
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