Journal of Environmental Chemical Engineering
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2024
·
IF 7.4
Min Chen,Jiangzhou Luo,Jun Hu,Yuxuan Zhao,Honglei Ling,Xueping Zong,Song Xue
The network polyimide (PI) precursor is a promising candidate to fabricate the advanced carbon molecular sieve (CMS) membrane since its robust crosslinked structure could prevent pore structure collapse during CMS formation. Exploring the relationship between network PI precursor structure and CMS membrane is highly significant. Herein, a novel brominated network PI precursor was fabricated via in-situ cross-linking technique firstly, and then the thermally induced bromination/debromination process was applied to tune the microporosity and gas transport properties of network PI precursor and its derived CMS membranes. After the bromination/debromination and carbonization at 550 °C, the resultant CMS membrane exhibited both high gas permeability and gas selectivities compared to its un-brominated network PI precursor derived CMS membrane. This is due to the bromination/debromination and carbonization enable the CMS membrane possesses large d -spacing values (11.06 Å), high BET surface areas (538.57 m 2 /g), and high percentage (∼71 %) of ultra-micropores. For instance, 6F-TA/TA-Br-550/30 membrane exhibits great CO 2 /CH 4 separation ability, with a CO 2 permeability of 6300 Barrer and a CO 2 /CH 4 selectivity of 46.11, which is suppressed the latest 2019 trade-off curves. We anticipate that the present bromination/debromination and carbonization could provide a fresh perspective on the rational design of network PI precursor and its derived CMS membrane with excellent gas separation performance.
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ACS Applied Materials & Interfaces
·
2012
·
IF 4.525
Ting Huang,Renguo Lu,Chao Su,Hongna Wang,Zheng Guo,Pei Liu,Zhongyuan Huang,Haiming Chen,Tongsheng Li
Herein, we have developed a rather simple composite fabrication approach to achieving molecular-level dispersion and planar orientation of chemically modified graphene (CMG) in the thermosetting polyimide (PI) matrix as well as realizing strong adhesion at the interfacial regions between reinforcing filler and matrix. The covalent adhesion of CMG to PI matrix and oriented distribution of CMG were carefully confirmed and analyzed by detailed investigations. Combination of covalent bonding and oriented distribution could enlarge the effectiveness of CMG in the matrix. Efficient stress transfer was found at the CMG/PI interfaces. Significant improvements in the mechanical performances, thermal stability, electrical conductivity, and hydrophobic behavior were achieved by addition of only a small amount of CMG. Furthermore, it is noteworthy that the hydrophilic-to-hydrophobic transition and the electrical percolation were observed at only 0.2 wt % CMG in this composite system. This facile methodology is believed to afford broad application potential in graphene-based polymer nanocomposites, especially other types of high-performance thermosetting systems.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Jun Long,Wenheng Huang,Huiting Li,Liang Chen,Jinchao Li,Jijun Chen,Aibing Lu,Yaping Zhang
Membrane with remarkable proton conductance and selectivity plays a key role in obtaining high vanadium flow battery (VFB) performance. In this work, the trade-off effect between proton conductance and vanadium ion blocking was overcome by the introduction of a cross-linking structure to prepare covalent cross-linked fluorine-containing sulfonated polyimide (CFSPI-PVA) membranes. Herein, the CFSPI-PVA-15 membrane possesses excellent comprehensive properties, including acceptable area resistance (0.21 Ω cm2), lower vanadium ion permeability (0.76 × 10–7 cm2 min–1), and remarkable proton selectivity (3.11 × 105 min cm–3) compared with the commercial Nafion 212 membrane. At the same time, the CFSPI-PVA-15 membrane exhibits higher coulomb efficiencies (97.26%–99.34%) and energy efficiencies (68.65%–88.11%) and a longer self-discharge duration (29.2 h) in contrast with the Nafion 212 membrane. Moreover, 500 cycles of the CFSPI-PVA-15 membrane at 160 mA cm–2 are also stably executed. The internal reasons for the improved chemical stability of the CFSPI-PVA-15 membrane are clarified from theoretical calculations with the mean square displacement value and fractional free volume. Therefore, the CFSPI-PVA-15 membrane exhibits great potential for application in VFB.
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MATERIALS CHEMISTRY AND PHYSICS
·
2016
·
IF 2.101
XinWei Shi,Hong Lian,XiaoSheng Yan,Ruiqiong Qi,Ning Yao,Tao Li
Negative thermal expansion Zr 2 WP 2 O 12 (ZWP) powder prepared by hydrothermal method was used as fillers to tailor the thermal expansion coefficient (TEC) of the polyimide (PI)-based composites. A series of PI-based composites containing different loading (0–40 wt% or 0–19.6 vol%) of ZWP powder were fabricated by the in-situ polymerization technique. Their structures and properties were characterized by Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Impedance meter, Thermal mechanical analysis (TMA) and Thermogravimetric analysis (TGA). The additions of ZWP steadily reduced the TEC of the PI matrix at all loadings studied. A 40 wt% (19.6 vol%) ZWP loading gives a 32.5% (about 15 × 10 −6 /K) reduction of TEC. The thermal stability of the ZWP/PI composites can be enhanced with the increment of ZWP powder. The independence of the dielectric constant on frequency is improved by introduction of ZWP particles to PIs. The dielectric loss displays good stability, which indicates that the ZWP/PI composites show potential applications in microelectronic and aerospace industries .
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NANO
·
2017
·
IF 1.025
Chunxia Wu,Xiaoliang Zhang,Hongwei Che,Jingbo Mu,Guangshuo Wang,Zhixiao Zhang,Guohua Cui
In this work, nano-convex-patterned polyimide surface (notated as 1-sample) and nano-concave-patterned polyimide surface (notated as 2-sample) were prepared by self-assembly and etching. Atomic force microscope (AFM) with a colloidal probe was used to examine the adhesion and nano-tribological behavior of the 1-sample and 2-sample. Results suggest that the 1-sample and 2-sample can decrease the surface friction and adhesive forces because of the decreased contact area between the contacting pairs. The friction forces of the 1-sample and 2-sample increased with the increase in sliding velocity and applied load. Moreover, the nano-concave pattern is more effective in reducing the adhesive force than the nano-convex pattern because of its higher surface roughness. However, the nano-convex patterning is more effective in reducing the friction force than the nano-concave patterning because of the smaller area of contact between the 2-sample and the colloidal probe.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
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2017
·Vol. 164
·期 6
·B285
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IF 3.259
Xuan Shen,Xiaohong Xia,Yongling Du,Weichun Ye,Chunming Wang
AuPd bimetallic composite has been prepared on reduced graphene oxide/polyimide (PI/RGO) film by electrodeposition. The AuPd fabricated on PI/RGO film exhibits good conductivity and excellent catalytic properties. AuPd/PI/RGO electrode shows high activity toward hydrogen peroxide (H2O2) for coupling effect between AuPd and PI/RGO film. Based on high electrochemical activity toward H2O2, an amperometric glucose biosensor has been also described, which was achieved by the immobilization of glucose oxidase (GOx) onto the AuPd/PI/RGO electrode. The proposed biosensor displayed good amperometric response characteristics toward glucose, such as a fast response within 3 s and a wide linear range from 0.024 mM to 4.6 mM. In addition, the biosensor was utilized for the detection of glucose in human blood serum that displayed satisfactory results. The present finding might open up a new avenue in the development of high performance bimetallic materials on appropriate supporting materials for electrochemical sensing.
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Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 11
·2134-2146
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IF 5.066
Xingfeng Lei,Yanhui Chen,Mingtao Qiao,Lidong Tian,Qiuyu Zhang
Low-dielectric polyimide (PI) is on high demand in the next generation of high-density and high-speed integrated circuits. The introduction of fluorine or pores into PIs has been reported to efficiently obtain low-dielectric properties, but unavoidably deteriorate the mechanical and/or thermal properties. Therefore, it is a great challenge for PI to decrease its Dk and simultaneously maintain its mechanical and thermal properties. Herein, a series of robust PI films were fabricated by copolymerizing amine-functionalized hyperbranched polysiloxane (HBPSi) with pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA). The outstanding dielectric properties were achieved in a 35 wt% HBPSi PI film, which exhibits a Dk as low as 2.24 (1 MHz), mainly owing to the enhanced free volume and dielectric confinement effect afforded by the bulky HBPSi. Meanwhile, 35 wt% HBPSi PI demonstrates remarkable thermal stability and admirable mechanical properties, with the glass transition temperature of 388 °C, 5% weight loss temperature in argon flow up to 554 °C, a tensile strength of 80.6 MPa, elongation at break of 13.7% and a tensile modulus of 1.36 GPa. It also demonstrates conspicuous film homogeneity and planarity with the surface roughness as low as 0.42 nm and good moisture resistance with water uptake less than 1.5%. The prominent comprehensive properties make HBPSi PI a strong candidate for the future interlayer dielectrics.
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Junchuan Wang,Yunchen Long,Ying Sun,Xueqin Zhang,Hong Yang,Baoping Lin
High energy density polymer nanocomposites with high-temperature resistance are quite desirable for film capacitors and many other power electronics. In this study, polyimide-based (PI) nanocomposite films containing the core-shell structured barium titanate@silicon dioxide (BT@SiO 2 ) nanofibers have been successfully synthesized by the solution casting method. In the BT@SiO 2 /PI nanocomposite films, the dielectric permittivity as well as the breakdown strength increase significantly. The SiO 2 shell layers with moderate dielectric permittivity could effectively mitigate the local field concentration induced by the large mismatch between the dielectric permittivity of BT and PI, which contributes to the enhancement of the breakdown strength of the PI nanocomposite films. As a result, the PI nanocomposite film filled with 3 vol% BT@SiO 2 nanofibers exhibits a maximal energy density of 2.31 J cm −3 under the field of 346 kV/mm, which is 62% over the pristine PI (1.42 J cm −3 at 308 kV/mm) and about 200% greater than the best commercial polymer, i.e. biaxially oriented polypropylenes (BOPP) (≈1.2 J cm −3 ). The thermogravimetric analysis results indicate that the BT@SiO 2 /PI nanocomposite films have good thermal stability below 500 °C.
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ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Cuiling Zhang,Shiming Zhang,Yinghan Yan,Fei Xia,Anni Huang,Yuezhong Xian
A new fluorescent polyimide covalent organic framework (PI-COF) has been successfully synthesized through solvothermal route using tetra(4-aminophenyl) porphyrin and perylenetracarboxylic dianhydride, which possesses porous crystalline and excellent thermal stability (>500 °C). Furthermore, few-layered PI covalent organic nanosheets (PI-CONs) can be easily obtained from the fluorescent PI-COF through a facile liquid phase exfoliation approach, which were confirmed by atomic force microscopy and transmission electron microscopy analysis. It is interesting that the fluorescent intensity of PI-CONs is obviously enhanced relative to that of PI-COF. The PI-CONs have been successfully utilized as an efficient fluorescent probe for the highly sensitive and selective detection of 2,4,6-trinitrophenol (TNP). The mechanism might be attributed to the combination of electron transfer and inner filter effect based on DFT calculations and spectral overlap data. The system exhibits a good linear response toward TNP over the range from 0.5 to 10 μM with a detection limit of 0.25 μM.
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RSC Advances
·
2015
·Vol. 5
·期 93
·76476-76482
·
IF 3.84
Zhenxun Huang,Shumei Liu,Yanchao Yuan,Jianqing Zhao
Pure silica zeolite nanocrystal particles functionalized with aminopropyl groups (APSZN) were introduced into a 2,2-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl polyimide (FPI) matrix to obtain FPI/APSZN hybrid films. The effect of APSZN content on the hybrid films was carefully evaluated in terms of UV-visible transmittance, dielectric constant (κ), coefficient of thermal expansion (CTE), mechanical properties, dynamic mechanical properties and thermal degradation behavior. The κ of the FPI/APSZN hybrid film decreases to 2.56 with 7 wt% APSZN. With increasing content of APSZN the tensile strength and the Young's modulus of FPI/APSZN films increase, while the CTE of FPI/APSZN hybrid films decreases. This study provides a novel approach to prepare low-κ FPI hybrids with enhanced properties.
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CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
M. Wang,W.L. Li,Y. Feng,Y.F. Hou,T.D. Zhang,W.D. Fei,J.H. Yin
BaTiO 3 nanowires/polyimide (BT-NWs/PI) and BaTiO 3 nanoparticles/polyimide (BT-NPs/PI) composites with low volume (≤10vol%) fraction of ceramic fillers were successfully prepared by in-situ dispersive polymerization. The BT-NWs were synthesized by a simple one-step hydrothermal method . The microstructure, dielectric properties , and energy storage density of the composites were studied. It was found that the two types of fillers were dispersed homogeneously in the PI matrix. Compared with BT-NPs/PI composites, the dielectric constant of composites filled by BT-NWs was larger at the same concentration. Stronger interfacial polarization mainly determined the dielectric properties that we observed on BT-NWs/PI composites. Furthermore, the energy storage density of the composites was significantly enhanced by BT-NWs, and energy storage density of 1.06 J/cm 3 was obtained under an electric field of 2200 kV/cm with the BT-NWs content of 2 vol%, which was 37% larger than that of the pure PI. The results indicate that the introduced wire-like ceramic fillers contribute to the enhancement of the dielectric properties and energy storage density of the composites.
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CHEMISTRY OF MATERIALS
·
2015
·
IF 8.354
Linli Xu,Shidong Jiang,Baopeng Li,Wenpeng Hou,Guoxing Li,Mushtaque A. Memon,Yong Huang,Jianxin Geng
Close-celled aromatic polyimide (PI)/graphene foams with low density and improved flexibility were fabricated by thermal foaming of poly(amic ester)/graphene oxide (PAE/GO) precursor powders. The PAE/GO precursor powders were prepared by grafting GO nanosheets with PAE chains, which led to efficient dispersion of the GO nanosheets in PAE matrix. Incorporation of GO resulted in an enhanced foaming capability of the precursor, i.e., enlarged cell size and decreased foam density. Notably, a decrease of 50% in the foam density was obtained via the addition of only 2 wt % GO in the precursor. In the foaming process, the GO nanosheets functioned as a versatile agent that not only provided heterogeneous nucleation sites but also produced gaseous molecules. By analyzing the foaming mechanism, the excellent features of GO in heat transfer, gas barrier, and strength reinforcement also facilitated to obtain large and uniform cells in the foams. In addition, the PI/graphene foams exhibited a prominent flexibility and enhanced flexural strength, as an elastic-to-nonelastic conversion of the initial stage of the compressive stress–strain curves was observed by increasing the content of graphene in the PI matrix and an increase of 22.5% in flexural strength was obtained by addition of 0.5 wt % GO in the precursor.
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