Journal of Energy Storage
·
2021
·
IF 6.583
Wenhao Xu,Yunhua Lu,Haijun Chi,Hongbin Zhao,Junyi Hu,Guoyong Xiao
In this work, the hydroxyl-containing polyimide(HPI) nanofibers were fabricated by the electrospinning of poly(amic acid)(PAA) derived from pyromellitic anhydride(PMDA) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6FAP), followed by thermal imidization. After further thermal rearrangement from HPI to polybenzoxazole(PBO) and pyrolysis, the HPI-based carbon nanofibers(HPICNFs) were obtained with abundant nitrogen and oxygen doping content. The effects of PAA concentration, thermally rearranged time and carbonizing temperature on the electrochemical performance of HPICNFs were evaluated. When the PAA concentration was 20%, the thermal rearrangement time was 2 h and the carbonization temperature was 800 °C, the specific surface area and pore volume of the HPICNFs reached 1107.6 m 2 g −1 and 0.6204 cm 3 g −1 . Due to the abundant micro- and mesoporous structures, the HPICNFs exhibited a high specific capacitance of 263.9 F g −1 and excellent capacity retention rate about 75% from 0.5 to 10 A g −1 . After 10,000 charging and discharging cycles, the capacitance retention of the symmetrical coin cell was maintained at about 99.82%, indicating superior long-term charging-discharging cycle stability. Additionally, a light-emitting diode was successfully lighted up by the three coin cells. Thus, this work provides a facile way to prepare the HPICNFs by thermal rearrangement and carbonization, which are expected to be used as high-performance electrode materials for supercapacitors.
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 9
·5283-5296
·
IF 2.599
Li Qing,Wang Yueyin,Zhang Shulai,Pang Long,Tong Hao,Li Jing,Xu Zushun
A series of fluorinated random co-polyimide/amine-functionalized zeolite MEL50 hybrid films (co-FPI/MEL50-NH 2 ) was successfully prepared with the addition of MEL50-NH 2 (e.g., 0, 1, 3, 5, 7 wt% of the co-FPI). Thereinto, zeolite MEL50 was synthesized by hydrothermal method and co-FPI was obtained by random copolycondensation from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride (BPADA), 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4,4′-diaminodiphenyl ether (ODA). Then, the properties of the hybrid films such as morphology, thermal properties, UV transparency and dielectric constant were investigated to probe the effect of incorporation of MEL50 on PI matrix. The results showed that the thermal properties and low dielectric properties of the hybrid films were markedly enhanced to achieve the optimum with the addition of 3 wt% MEL50-NH 2 . In our results, the glass transition temperature increased up to 266 °C from 243 °C of the pristine co-FPI film and 5% weight loss temperature increased up to 527 °C from 517 °C of the pristine co-FPI film in nitrogen. The dielectric constant decreased down to 2.68 from 3.21 of the pristine co-FPI film. This convenient approach provides a possibility of making PI possess both enhanced thermal properties and low dielectric constant, which is more applicable to microelectronics.
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高影响因子
MATERIALS & DESIGN
·
2016
·
IF 3.997
Zhigeng Chen,Shumei Liu,Shijing Yan,Xia Shu,Yanchao Yuan,Haohao Huang,Jianqing Zhao
Low dielectric constant is desired for polyimide to be used in microelectronic industry. In the present study, a series of porous graphene fluoroxide/polyimide (GFO/pPI) nanocomposite films with improved dielectric and mechanical properties were fabricated. Polyethylene glycol (PEG) was introduced into the system to play the roles of an intercalator in exfoliation of graphite fluoroxide and a blowing agent in preparation of porous structure . The in-situ bubble-stretching, resulting from PEG decomposition during the thermal imidization, not only hindered the agglomeration of GFO nanosheets , but also generated micro-pores in PI matrix. Both the porous structure and the GFO nanosheets significantly decreased the dielectric constant of composite films , and the load transfer between GFO and PI matrix efficiently improved the mechanical properties of composite films . A very low dielectric constant of 2.29 as well as high tensile modulus of 4.43 GPa and tensile strength of 159 MPa was obtained for the composite film with the GFO loading of only 0.30 wt%. In addition, the glass transition temperature of GFO/pPI films was increased from 355 °C to 388 °C, and the coefficient of linear thermal expansion of GFO/pPI films was decreased from 48.7 ppm/K to 24.9 ppm/K.
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DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 24
·7360-7370
·
IF 6.641
Yingyi Ma,Le Xu,Zian He,Junwen Xie,Lei Shi,Mingyan Zhang,Wenlong Zhang,Weiwei Cui
The preparation and performance adjustment of low-dielectric polyimide (PI) play important roles in the development and application of next-generation dielectric materials used in high-speed integrated circuits. Herein, composite polyimide films with sandwich-type porous structures were fabricated via a microemulsion method, in which the self-assembly of water droplets was involved. Decreases in the dielectric constant and water absorption and increases in the tensile strength and tensile modulus were simultaneously realized due to the presence of symmetrical porous structures and a dense PI layer upon the introduction of the sandwich-type porous structure. The dielectric, mechanical and water resistance properties of the composite PI films could be further regulated by controlling the porous structure using different conditions for film formation. By varying the temperature, humidity, concentrations of polymer and surfactant in the microemulsion method, we obtained the low dielectric constants of 2.24–2.81 and the low water absorptions of 0.49–0.59%, with decreases from 15.73% to 32.81% and 76.02% to 80.08%, respectively, as compared to the case of the flat PI film; we also achieved the high tensile strengths of 97.7–103.2 MPa and high tensile moduli of 1.2–1.4 GPa, with the increases of 4.83–10.73% and 6.57–16.43%, respectively, as compared to the case of the flat PI film. Moreover, excellent durability of the low dielectric constant under high humidity condition was demonstrated by the very small increase in the dielectric constant (0.02–1%) in a moist environment. These results provide useful information for the structural design of high-performance dielectric materials.
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高影响因子
HIGH PERFORMANCE POLYMERS
·
2023
·
IF 2.1
Jinshui Lu,Jinyuan Zhang,Heng Liu,Weipeng Chen,Jiangrong Luo,Ziqing Wang,Tingting Cui,Yonggang Min,Yidong Liu
In this work, a new diamine was designed by connecting flexible structures such as ether bond and aliphatic carbon chain between benzene rings, and was synthesized and purified through simple reactions such as Suzuki reaction. Finally, a series of polyimide (PI) films were synthesized by copolymerization with 4.4`-diaminodiphenyl ether (ODA)\pyromellitic dianhydride (PMDA) in different proportions. We prepared polyimide films with new monomer copolymerization ratios of 1% (PI-1), 5% (PI-2), 10% (PI-3), and 20% (PI-4). The polyimide films showed excellent glass transition temperatures, which were attributed to their unique bent architectures. The mechanical and thermal properties of the thermosets were studied using tensile testing, static thermomechanical analysis (TMA), and thermogravimetric analysis (TGA). As the results, the films exhibited the optimal glass transition temperatures (317.56°C–381.91°C), and the component with the highest copolymerization ratio has a 15% decrease in glass transition temperature compared to the component without copolymerization. Moreover, PI-1-PI-4 showed good heat resistance in the N2 atmosphere. The temperatures corresponding to a 5% heat loss in the films (T5%) were 458.12 °C–548.75°C, respectively.
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DOI
高影响因子
SURFACE AND INTERFACE ANALYSIS
·
2021
·Vol. 54
·期 2
·156-164
·
IF 1.607
Li Jian
The TiO 2 is grafted by triethylamine and is introduced on the surface of the carbon fiber, which improves the wettability and activity of the carbon fiber surface and at the same time strengthens the carbon fiber/polyimide composite. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the triethylamine grafting successfully on TiO 2 . Scanning electron microscope (SEM) results show that when the trimethylamine concentration is 1.0%, a uniform coating is formed on the surface of the carbon fiber. The interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) were increased by 32% and 69%, respectively.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2015
·Vol. 91
·期 3
·777-785
·
IF 2.349
Jianqiang Wang,Keying Song,Bing Cao,Li Li,Kai Pan
BACKGROUND Polyimide (PI) solvent-resistant nanofiltration (SRNF) membranes were prepared by a two-step method. The polyamic acid (PAA) precursor was synthesized first, and then PAA membranes were obtained via a non-solvent induced phase separation method. Finally, the PAA membranes were transformed into PI membranes by the thermal imidization method. The effect of molecular weight of precursor on the structure and performance of PI membranes was investigated in detail. In addition, the influence of other processing parameters, such as evaporation time and immersion time in the coagulation bath, on the performance of PI membranes prepared from PAA with different molecular weights was also investigated. RESULTS The results showed that the structure of PI membrane varied with PAA molecular weight. The PI membranes prepared from low molecular weight PAA failed to form a defect-free membrane with enough strength, and resulted in high flux but low rejection. Accordingly, PI membranes processed from PAA with high molecular weight retain rejection higher than 90% of FCF with decreased flux. The results also indicated that the optimized molecular weight of PAA should be between 1.23 × 10 5 g mol −1 and 2.44 × 10 5 g mol −1 to prepare defect-free PI membrane for nanofiltration. The results also showed that the performance of the PI membranes can be controlled by adjusting the evaporation time, immersion time, and also the operating pressure. CONCLUSIONS The PAA molecular weight has a great effect on the morphology and performance of PI membranes. A suitable PAA molecular weight is necessary for preparing defect-free PI nanofiltration membrane. © 2015 Society of Chemical Industry
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Ziheng Ye,Feihua Liu,Xiaoai Ye,Kaizheng Gao,Jingjing Luo,Xiangli Liu,Weiwei Zhao
Ti 3 C 2 T x MXene with outstanding physicochemical properties have shown huge potential in electromagnetic interference (EMI) shielding applications. However, the poor chemical stability and mechanical fragility have seriously hindered their practical use. Herein, we developed a novel pyrimidine-containing polyimide (PPI) and constructed Ti 3 C 2 T x /PPI (MP) composite films . The incorporation of PPI not only suppresses the oxidation of Ti 3 C 2 T x by forming Ti-N x interactions between the nitrogen-rich pyrimidine rings of PPI and the Ti centers of Ti 3 C 2 T x , but also enhances mechanical strength and durability of the composite film across a wide temperature range (-196–250 ℃). Compared with Ti 3 C 2 T x film, the MP film exhibits significantly improved oxidation resistance , which the EMI SE of MP film did not decrease after 14 days in 80 ℃/80 RH environment when the weight ratio of Ti 3 C 2 T x and PPI reaches 11:4. Merely 1.4 dB decrease in EMI SE of the MP film was revealed after 200,000 bending cycles with a radius of 2 mm, and the EMI SE remained virtually unchanged after bending in liquid N 2 . Moreover, the composite film demonstrates excellent thermal management properties, including rapid thermal response, efficient electrothermal conversion, excellent durability and stability. The combination of desirable EMI shielding ability, ultrahigh flexibility, superior stability and durability, as well as ideal thermal management performance gives this material excellent potential for various applications.
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Ke Liu,Qisong Liu,Rui Fan,Hongfa Huang,Hua Yi,Chao Hu
Mixed matrix membranes (MMMs) incorporating metal–organic frameworks (MOFs) as fillers show attractive selectivity and permeability for gas separation. However, the performance improvement is restricted by undesirable interfacial interaction and inhomogeneous dispersion of MOFs in the membrane matrix. In this paper, amino-functionalized UIO-66 (U6N) with high porosity was employed as a filler and further regulated by a controlled plant polyphenol-induced surface modification strategy. The process involved the formation of tannic acid-iron(III) complex (TA-Fe(III)) on the U6N surface, which improved interfacial compatibility with the polyimide matrix while introducing abundant hydroxyl groups to enhance gas transport properties. Accordingly, the modified MMMs containing 30 wt.% U6N@TA-Fe(III) achieved optimized gas separation performance. Specifically, the CO 2 permeability increased to about 2495.9 Barrer with a CO 2 /CH 4 selectivity of 19.32, which exceeded the 2008 Robeson upper limit and showed an increase of 22.1% and 25.6%, respectively, compared to the MMMs embedded with unmodified U6N. Moreover, the improved dispersion of the U6N@TA-Fe(III) within the membrane structure is conducive to improving separation performance for CO 2 /N 2 and O 2 /N 2 . Therefore, this work provides a novel insight into the rational design of the MMMs via a facile modification strategy, which can further improve the gas separation performance of the MMMs.
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Changchao Sun,Yongjun Kang,Bingxue Liu,Daolei Lin,Guofeng Tian,Shengli Qi,Dezhen Wu
Nickel-rich layered oxide cathodes (LiNi0.8Co0.1Mn0.1O2, NCM811) have shown great promise in high-energy-density lithium-ion batteries due to their high specific capacity. However, their practical application is severely hampered by structural instability, interfacial side reactions, and transition metal dissolution. To address this issue, in the present work, a highly polar polyimide containing sulfonyl moiety (named PI (6FOS)) is designed and utilized as a functional interfacial coating layer on NCM811 by copolymerizing 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 4,4′-oxidianiline (ODA) and 4,4′-diaminodiphenyl sulfone (DDS). The combination of high polar constant and superior interfacial stability of PI (6FOS) contributes to effective suppression of electrolyte decomposition and transition metal dissolution. The strong interactions between polar trifluoromethyl and sulfonyl groups in the molecular chain and NCM811 particles enhance interfacial stability and facilitate lithium-ion transport. As expected, the PI (6FOS)/NCM811 electrode exhibits excellent long-term cycling performance with a remarkable capacity retention of 94% over 100 cycles at 0.2 C and 83% over 300 cycles at 1 C within 2.5–4.3 V. Even under high-voltage conditions (4.7 V), it maintains 59% capacity retention after 300 cycles at 1 C. The PI (6FOS)/NCM811 electrode shows outstanding rate capability, with a discharge specific capacity of 140.3 mAh g–1 at 5 C. Meanwhile, the presence of the polyimide coating layer increases the thermal decomposition temperature of the cathode material and reduces heat generation. The perspective of the coating design strategy based on sulfonyl-containing polyimide modification offers a novel path toward high-stability cathodes for high-energy-density and high-safety lithium-ion batteries.
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产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2018
·
IF 2.955
Xiangfei Zheng,Jingcheng Liu,Kuan Wang,Ren Liu,Yan Yuan,Xiaoya Liu
Polyimide/amino-modified reduced graphene oxide (PI/AMG) composite matrix were synthesized through the condensation reaction of 4,4'-diaminodiphenyl ether, 3,5-diaminobenzoic acid, diphthalic anhydride, and AMG. Subsequently, the double bonds were incorporated into the matrix through the reaction of glycidyl methacrylate (epoxide group) and the carboxyl group on PI/AMG. UV-cured composite films were then prepared and performance was evaluated. The results revealed that the tensile strength and elongation at break could reach a maximum of 108.7 MPa and 46.4%, which represented increases of 102.8% and 354.9%, respectively, compared with the GPI/AMG 0% film. The water absorption decreased from 0.64% to 0.27%. And their surface resistivity reached 10 6 –10 9 Ω, an increase of approximately eight orders of magnitude.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 6
·4743-4751
·
IF 2.22
Wang Runfei,Cai Peizhi,Xu Wei,Tan Ruiqin,Shen Wenfeng,Wang Zhaozhao,Chen Guofei,Huang Jian,Fang Xingzhong,Song Weijie
In the past years, transparent film heaters (TFHs) based on silver nanowires (AgNWs) have attracted much attention because of their high transmittance, excellent flexibility, and great thermal response. In this paper, we fabricated flexible TFHs with a sandwich structure composed of Ga-doped ZnO (GZO) and AgNWs on the colorless polyimide (cPI) substrate. The optimized hybrid film exhibited a sheet resistance of 14.6 Ω sq −1 with a transmittance of 79%. Excellent thermal uniformity and heating stability of TFHs were demonstrated. The thermal response tests of the GZO/AgNW/GZO/cPI TFHs showed high saturation temperature (~ 176 ℃) with low input voltage (~ 6 V), fast response time (~ 15 s), and stable heating performance. These results indicate that the flexible TFHs with a GZO/AgNW/GZO sandwich structure have broad potential applications in flexible electronic devices.
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高影响因子
危险品化学品经营许可证（带存储）