Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 20
·10738-10747
·
IF 11.9
Xiaofeng Li,Bin Zhang,Jing Guo,Yaohan Chen,Lei Dai,Jifu Zheng,Shenghai Li,Suobo Zhang
The preparation of self-supporting anion exchange membranes with enhanced mechanical strength and ultrathin thickness is still a challenge to improve the performance of fuel cells. In this work, we developed 9-dodecylidene-9H-fluorene (DDF) as a branched monomer to construct branched structures based on poly(arylene piperidinium)s. After introducing a 2.5% molar ratio of DDF, quaternized poly(piperidinium-triphenyl-dodecylidenefluorene) (PPTDF-QA) possesses low water swelling (below 25% at 80 °C) and high mechanical strength (over 70 MPa). The obvious phase-separation behavior of the branched membranes induced by the long alkyl chain improves hydroxide conductivity which reaches 168 mS cm−1 at 80 °C. Meanwhile, the thickness of branched PPTDF-QA can be optimized to 8 μm. The present work reveals that a facile branched monomer can promote the formation of a microphase-separated morphology of the membrane to fabricate high-performance anion exchange membranes.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 140
·期 7
·e53497
·
IF 3.057
Jilei Xu,Ping Chen,Shuaijiang Ma,Guohao Zhu
In this work, three bismaleimides containing cardo and ortho -oxazine structures, with dual advantages of bismaleimide and benzoxazine resins, were synthesized. Their chemical structures were characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The polymerization behaviors of bismaleimides were investigated using non-isothermal differential scanning calorimetry and in situ Fourier transform infrared spectroscopy. Results showed that the inclusion of both, bismaleimide and benzoxazine, provided a new structure with better thermal stability and solubility, as compared to the same type and commercial bismaleimides. The ortho-oxazine functionalized bismaleimide resin exhibited excellent thermal stability up to 440°C, whereas the carbon residue rate reached 73% at 800°C. Additionally, further thermal rearrangement of the internal structure of the polymer at high temperature provided a benzoxazole structure that had better thermal stability. The rearrangement due to the thermal changes was confirmed by in situ FTIR and solid-state 13 C-NMR spectroscopy. Based on the micro calorimetry characterization, it is found that both the bismaleimide and the benzoxazole resins formed after thermal rearrangement have excellent flame-retardant properties.
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THERMOCHIMICA ACTA
·
2022
·
IF 3.378
Jilei Xu,Ping Chen,Shuaijiang Ma,Guohao Zhu,Lihao Wu
In this work, three bismaleimides containing cardo and ortho -oxazine structures, with dual advantages of bismaleimide and benzoxazine resin, were synthesized. Their chemical structures were characterized by Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The kinetics of curing and kinetic model were investigated by non-isothermal differential scanning calorimetry. The curing reaction of the bismaleimide was studied by in-situ FT-IR spectroscopy. Studies showed that both bismaleimide and benzoxazine provided the new structure with better thermal stability and solubility, compared to similar type of materials and commercial bismaleimides. Additionally, the further thermal rearrangement of the internal structure of the polymer at high temperature formed a benzoxazole structure with higher thermal stability. The rearrangement due to thermal changes was confirmed by in-situ FT-IR and solid-state 13 C-NMR spectroscopy. Microscale combustion calorimetry (MCC) showed that both, bismaleimide and benzoxazole resins, were formed after thermal rearrangement and had excellent flame-retardant properties.
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MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Yahuan Li,Yang Li,Qingyun Chang,Xiaohuan Zang,Shuaihua Zhang,Chun Wang,Zhi Wang
MXene-polyvinylpyrrolidone (MXene-PVP) was first prepared by physically doping combined with spray drying, which can overcome the aggregation of the MXene. Then, the MXene-PVP was carbonized to result in a carbonized MXene-PVP (MXene-PVP-C), which was then immobilized on stainless steel wire by sol–gel approach to prepare a new solid-phase microextraction (SPME) fiber. The prepared MXene-PVP-C coated fiber was studied for the extraction of 10 polycyclic aromatic hydrocarbons (PAHs) from tea beverages by using SPME method prior to gas chromatographic detection. The main SPME parameters, including extraction temperature, extraction time, salt concentration, sample solution pH and stirring rate, were investigated by central composite design methodology. Under the optimized conditions, the developed method gave the limits of detection of 0.03–0.15 µg/L, and the limits of quantification of 0.10–0.50 µg/L for the PAHs. The method recoveries for the PAHs in spiked tea beverages ranged from 78.6 % to 122 %. The single-fiber and fiber-to-fiber relative standard deviations were lower than 8.2 % and 9.6 %, respectively.
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TALANTA
·
2020
·
IF 5.339
Pengli Guan,Yaoming Liu,Binsheng Yang,Yanbo Wu,Jie Chai,Guangming Wen,Bin Liu
To realize accurate regulation for fluorescent substrate of lipase, two series compounds ( I , II ) with similar structure were designed and synthesized. The flexible diphenylmethane was permitted I to go deep into the catalytic site of lipase, while rigid structure of 9H-fluoren makes itself difficult to approach the center. Series I could be effectively hydrolyzed by porcine pancreatic lipase (PPL), and the product emitted fluorescence based on aggregation-induced emission (AIE) mechanism, meanwhile different substituent groups (–Br, –Cl, –Ph, –H) on I induced the tunable hydrolysis rate. The limit of detection (LOD) was 0.05 U/mL, and linear calibration range was 0.1–4.0 U/mL, this would be effectively applied to biological detection. This result was well supported by theories calculation and molecular docking. Moreover, substrate 1 was selected to describe the distribution of lipase in many living biology such as zebrafish , Locusta migratoria and Helianthus annuus seeds coat. It was found that lipase and lipid droplets (LDs) coexist in biological systems, but there is no lipase in LDs. The designed probe gives us an opportunity to describe lipase distribution in many important tissues, including biology and medical science.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2020
·
IF 2.627
Cui-Ping Ye,Ya-Fei Qiao,Rui-Nan Wang,Wen-Ying Li
To identify the effect of solvents and anthracene on the purification of carbazole, the solvent crystallization of carbazole was investigated with xylene, chlorobenzene and tetrachloroethylene (TCE) as solvents under two forced circulation cooling (FCC) modes. The co-crystalline experimental data were obtained from runs carried out at different anthracene levels between 1% (mass) and 10% (mass). The results showed that a uniform flake carbazole crystal obtained when using xylene and chlorobenzene under the FCC-1 mode with gradual cooling rate. Nevertheless, fine flake crystals grown under shock cooling of FCC-2 mode. It is beneficial to improving the purity of carbazole with chlorobenzene as solvent under cooling mode of FCC-1. Anthracene could promote the growth of carbazole in solution, and it has a significant influence on the purification of carbazole.
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JOURNAL OF CHROMATOGRAPHY A
·
2021
·
IF 4.759
Jinqiu Li,Bin Zhao,Liying Guo,Zhuo Wang,Chun Wang,Zhi Wang,Shuaihua Zhang,Qiuhua Wu
Three novel hypercrosslinked polymers (HCPs) were synthesized via Friedel-Crafts reaction employing 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene as alkylating agent, and triphenylbenzene, tetraphenylethylene and p -quaterphenyl as the aromatic units, respectively. The prepared HCPs were applied as solid-phase microextraction coatings for direct immersion extraction of polycyclic aromatic hydrocarbons (PAHs) and their oxygenated and nitrated derivatives in environmental water samples. The key factors affecting the extraction efficiency including extraction time, extraction temperature, stirring rate, ionic strength and desorption conditions, were carefully studied. Coupled with gas chromatography mass spectrometry analysis, a new method for determining PAHs and their derivatives was developed. Under the optimized conditions, the limits of detection ( S/N =3) and limits of quantitation (the lowest concentration for quantification) of the method were in the range of 2.5-25.0 and 7.5-75.0 ng L −1 , respectively. The recoveries of spiked samples were in the range of 73.1-118.3% with relative standard deviations less than 13.0%. The developed method was applied for the simultaneous determination of nine PAHs and their derivatives in environmental water samples, showing good accuracy and reliability.
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HIGH PERFORMANCE POLYMERS
·
2019
·
IF 1.584
Yayun Zheng,Xing Yang,Meng Yuan,Jujie Luo
Two novel gas separation membranes (Phenyl(Ph)-poly(ether ether ketone)s (PEEKs) and PEEKs) based on PEEKs with a high fractional free volume were designed and synthesized. The structure and thermodynamic stability of the membranes were investigated using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The two membranes, which were determined to be high-molecular weight polymers by gel permeation chromatography, showed good solubility in a weakly polar solvent. The gas transport properties of the Ph-PEEK membranes were investigated for different gases (CO2, O2, CH4, and N2) at 25°C and 1 atm. The Ph-PEEK-3 membrane with the largest free volume had the largest gas permeability coefficient and maintained good selectivity. The effect of operating temperature on the gas permeation of the Ph-PEEK-3 membrane was also investigated, and the maximum permeability of the four single gases was reached at 55°C and 1 atm.
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JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Yi Zhi Zhuo,Ao Nan Lai,Qiu Gen Zhang,Ai Mei Zhu,Mei Ling Ye,Qing Lin Liu
Anion exchange membrane fuel cells (AEMFCs) have become one of the most promising energy-conversion devices due to the potential of adopting non-noble metal catalysts and faster oxygen reduction reaction kinetics in an alkaline operating environment. Here, a series of anion exchange membranes with high ionic-conductivity and low swelling ratio were prepared from imidazolium-functionalized crosslinked cardo poly(arylene ether sulfone)s for AEMFCs. Two oligomers, tertiary amine-containing poly(arylene ether sulfone) (PES-DA) and bromomethyl-containing poly(arylene ether sulfone) (BPES), are synthesized and then mixed at −40 °C. They are spontaneously inter-crosslinked at room temperature to form dense anion exchange membranes (AEMs), in which the tertiary amine groups of PES-DA rapidly react with the bromomethyl groups of BPES to form the crosslinked bonds. This avoids the use of crosslinking agents and the expense of functional groups. The resulting membranes show a high hydroxide conductivity up to 82.4 mS cm −1 at 80 °C and a slight swelling low to traditional AEMs due to its crosslinked network structure. An open circuit voltage (OCV) of 0.82 V and a maximum power density of 92.1 mW cm −2 are achieved in a H 2 /O 2 single cell. The as-prepared membranes have a great potential for the application in AEMFCs.
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JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Dong Guo,Chen Xiao Lin,En Ning Hu,Lin Shi,Faizal Soyekwo,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Clustered alkyl side chains bearing a string of three imidazolium cations with hexyl spacers are grafted to fluorene-based poly (arylene ether sulfone) successfully. Nanostructure is directly configured within the anion exchange membranes (AEMs) via the novel multi-cation side chains. As confirmed by atomic force microscopy (AFM) and small angle X-ray scattering (SAXS), percolating OH – conducting channels with the size of ionic clusters nearly 20 nm endow the trimPES-0.4 membrane with an excellent ion conductivity in excess of 120 mS cm –1 at 80 °C. Because of the self-assembly of ionic groups, water molecules are compartmentalized into the hydrophilic side chain regions instead of backbones, resulting in advantageous over water management. Together with the lengthened hydrophobic segments, TrimPES-0.2 exhibits superior dimensional stability (12.0%, 30 °C) to conventional mono-cation type AEMs. Furthermore, the novel multi-cation TrimPES-0.4 displays a peak power density of 134.4 mW cm –2 at a current density of 280 mA cm –2 . Therefore, these findings suggest that by tuning the distribution of cations, AEMs with well-balanced performance can be made for fuel cell applications .
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HIGH PERFORMANCE POLYMERS
·
2017
·
IF 1.179
Tengyang Zhu,Xing Yang,Xiaoqi He,Yayun Zheng,Jujie Luo
A series of new aromatic polyamides (PAs) and copolyamides (CPAs) containing fluorene group have been synthesized through polycondensation reaction. The chemical structure was confirmed by Fourier transform infrared and proton nuclear magnetic resonance (1H NMR). PAs and CPAs exhibited the higher thermal stability (Td15 > 378°C in nitrogen), the higher glass transition temperature (Tg > 345°C), and excellent solubility in polar solvent. Gas transport properties of the PA and CPA membranes were investigated using different single gases (hydrogen (H2), carbon dioxide (CO2), oxygen (O2), methane (CH4), and nitrogen (N2)). We discussed the effect of chemical structure and operating temperature on gas transport properties. The results show that PA-1 containing a hexafluoroisopropylidene moiety exhibited the highest gas permeability (PH2 = 12.71 Barrer, PCO2 = 12.26 Barrer, and PO2 = 2.62 Barrer) and reasonably good selectivity (α(H2/N2) = 27.63, α(CO2/N2) = 26.65, and α(O2/N2) = 5.70) at 25°C and 1 atm. For all the membranes, gas permeability gradually increased with the increase in operating temperature, while the selectivity gradually decreased. These gas permeation results were well correlated with fractional free volume, interchain d-spacing (dsp), and intermolecular interaction.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Dong Guo,Ao Nan Lai,Chen Xiao Lin,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
With the intention of optimizing the performance of anion-exchange membranes (AEMs), a set of imidazolium-functionalized poly(arylene ether sulfone)s with densely distributed long flexible aliphatic side chains were synthesized. The membranes made from the as-synthesized polymers are robust, transparent, and endowed with microphase segregation capability. The ionic exchange capacity (IEC), hydroxide conductivity, water uptake, thermal stability, and alkaline resistance of the AEMs were evaluated in detail for fuel cell applications. Morphological observation with the use of atomic force microscopy and small-angle X-ray scattering reveals that the combination of high-local-density-type and side-chain-type architectures induces distinguished nanophase separation in the AEMs. The as-prepared membranes have advantages in effective water management and ionic conductivity over traditional main-chain polymers. Typically, the conductivity and IEC were in the ranges of 57.3–112.5 mS cm–1 and 1.35–1.84 mequiv g–1 at 80 °C, respectively. Furthermore, the membranes exhibit good thermal and alkaline stability and achieve a peak power density of 114.5 mW cm–2 at a current density of 250.1 mA cm–2. Therefore, the present polymers containing clustered flexible pendent aliphatic imidazolium promise to be attractive AEM materials for fuel cells.
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