POLYMER INTERNATIONAL
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2017
·Vol. 66
·期 11
·1633-1639
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IF 2.07
Nafeesa Mushtaq,Lala Rukh Sidra,Guofei Chen,Yongmei Tang,Lubo Xu,Xingzhong Fang
A series of cardo based asymmetric polyimides containing bulky rigid naphthalimide and phthalimide groups were prepared from asymmetric monomer bishaloimide and bisphenols by solution polycondensation. Bishalo(naphthalimide-phthalimide) monomers containing different terminal leaving groups (Cl, F, NO 2 ) were synthesized, and the reactivity difference of these monomers was compared for the successful synthesis of polyimides. The inherent viscosities of the polyimides were in the range 0.51 − 0.60 dL g −1 in N -methyl-2-pyrrolidone at 30 °C. These polyimides demonstrated good organosolubility and mechanical properties with tensile strengths of 93 − 120 MPa, tensile moduli of 3.5 − 5.3 GPa and elongations at break of 2.8% − 4.3%. The polyimides showed high glass transition temperatures ( T g ) ranging from 330 to 363 °C. The 10% weight loss ( T 10% ) of asymmetric polyimides reached 436 − 500 °C in nitrogen and 417 − 476 °C in air. The water uptake of the polyimides was in the range 0.35% − 0.72%. © 2017 Society of Chemical Industry
研究领域:
材料科学
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高分子化学
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高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2012
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IF 2.098
Shucai Liang,Hui Yu,Jin Xiang,Wang Yang,Xiaohui Chen,Yanbin Liu,Chen Gao,Guoping Yan
A new naphthalimide modified polyethylenimine (PEI) nanoparticles (called NPEI-NPs) was synthesized and applied as fluorescent probe for rapid, selective and sensitive fluorometric detection of trace DNA. The synthesis involved the covalent modification of PEI with 4-butylamino-N-carboxymethyl-1,8-naphthalimide(BACMN) for getting amphiphilic polymer. Then the amphiphilic polymer was self-assembled in water to give the NPEI-NPs. NPEI-NPs was soluble in water and emitted fluorescence at 545 nm with exciting at 460 nm. The fluorescence spectra resulting from the interaction between NPEI-NPs and DNA indicated that the fluorescence of NPEI-NPs increased in the present of DNA. Therefore, a fluorescence enhancement method was developed for the determination of trace fish sperm DNA (fsDNA) and calf thymus DNA (ctDNA). Under the optimal conditions, the calibration curves were linear over the concentration ranges of 0.05–2.8 μg/mL for fsDNA and 0.08–3.0 μg/mL for ctDNA. The detection limits for fsDNA and ctDNA were 1.6 and 2.0 ng/mL, respectively. The proposed method has been employed to quantify DNA in synthetic samples with the satisfactory results.
研究领域:
生物化学
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分析化学
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PubMed
高影响因子
POLYMER INTERNATIONAL
·
2011
·Vol. 61
·期 1
·111-117
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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
研究领域:
材料科学
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化学工程
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DOI
高影响因子
POLYMER
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2024
·
IF 4.1
Zhichao Wang,Yu Hu,Jianhua Hu,Haitao Wang
One-pot aqueous-phase synthesis of polyimides (PIs) offers great economic and environmental benefits and improves the hydrolytic stability of the precursor (polyamic acid) obviously. However, this method is only suitable for the polymerization of very limited dianhydride and diamine monomers up to now. In this study, the most commonly used dianhydrides and diamines for the preparation of commercially available PI products were selected for one-pot aqueous-phase synthesis of various polyamic acid salts (PAAS). The effects of the structure of monomers, the reaction temperature and the adding process of the organic base on the polymerization reaction were explored by rotational rheology, nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. The polymerization products obtained via the aqueous-phase route show high molecular weight when the reaction conditions have been optimized. Various PI films prepared by the thermal imidization of corresponding PAAS demonstrate good optical transparency, excellent thermal stability, and outstanding mechanical and electrical properties. This work proposes the reaction mechanism of PAAS via one-pot aqueous-phase route and utilizes this novel polymerization strategy to synthesize high-molecular-weight PIs from typical aromatic dianhydride and diamine monomers.
研究领域:
材料科学
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化学工程
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高影响因子
Small
·
2025
·
IF 12.1
Man Liu,Feihua Liu,Hongmei Qin,Chuanxi Xiong,Hengxue Xiang,Liping Zhu,Meifang Zhu
Polymer dielectric films are widely used in advanced electronics, hybrid vehicles, etc., however, they encounter critical challenges, including significant thermal degradation and heightened leakage currents, which severely constrain their energy density and efficiency under high-temperature conditions. Herein, a novel strategy is proposed for constructing a polyimide (PI) alloy by incorporating high-bandgap copolymer of perfluoropropyl perfluorovinyl ether and tetrafluoroethylene (P(TFE-PPVE)) and fluorinated polyimide (FPI) as a compatibilizer. The highly oriented structural PI/FPI/P(TFE-PPVE) alloy is fabricated via knife casting, which utilized high shear forces to align the P(TFE-PPVE) blocks within the polyamide acid. Simulation results indicate that the high-bandgap P(TFE-PPVE) phase (9.72 eV) with an oriented structure in the PI matrix can effectively suppress electrical tree growth. Furthermore, deep carrier trap at the PI/P(TFE-PPVE) interface (2.98 eV) further reduces leakage current and enhances breakdown strength while minimizing conduction loss. As a result, the PI/FPI/0.25P(TFE-PPVE) alloy demonstrates remarkable dielectric stability under diverse conditions, achieving a discharge energy density of 3.75 J cm −3 with 90% efficiency at 150 °C and 550 MV m −1 . This straightforward blending strategy provides an effective pathway to modulate the condensed structure of all organic polymers, offering promising potential for high-performance polymer dielectrics.
研究领域:
材料科学
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电子工程
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能源存储
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PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2018
·Vol. 93
·期 8
·2281-2291
·
IF 2.587
Xiao Wang,Xiaohui Ju,Tian-Zhi Jia,Qian-Cheng Xia,Jia-Lin Guo,Chen Wang,Zhaoliang Cui,Yong Wang,Weihong Xing,Shi-Peng Sun
BACKGROUND At present, most commercial nanofiltration (NF) membranes are negatively charged. An effective way to prepare a positively charged NF membrane is to cross-link polyimide (PI) substrate with polyethyleneimine (PEI). However, the lack of an efficient process for selecting proper cross-linking conditions is an important issue. Therefore, the major objective of this work is to develop an efficient method to cross-link only the top surface of the membranes. RESULTS The optimum cross-linking condition was found to be at a cross-linking temperature of 70 °C, cross-linking time of 80 minutes and stirring speed of 500 rpm. Comparing the membrane before and after cross-linking, the molecular weight cut-off changed from 17520 Da to 458 Da and the membrane surface changed from positive from negative. The cross-linked membrane showed high rejection (>95%) for basic dyes with different molecular weights and relatively high antifouling properties to these dyes (flux recovery ratio > 92%, total flux decline ratio < 26.7%, irreversible flux decline ratio < 7.3%). CONCLUSIONS Stirring speed was found to greatly influence the membrane performance. It was found that there exists an optimum stirring speed at which the cross-linker distributes evenly on the membrane surface for the most effective cross-linking to take place. The newly developed surface cross-linking method also may have the potential to modify other types of membrane surfaces. © 2018 Society of Chemical Industry
研究领域:
材料科学
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环境工程
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高影响因子
Polymers
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2023
·Vol. 15
·期 13
·2812
·
IF 5
Yingwei Zhang,Chunhua Wang,Yong Yi,Wenzhi Wang,Jun Yang
In order to adjust the properties of polyamide 6 (PA6) and expand its application, a new strategy of introducing an aromatic imide structure into the PA6 chain through the random copolymerization method is reported. The diimide diacid monomer was first synthesized by the dehydration and cyclization of pyromellitic dianhydride and 6-aminocaproic acid before it reacted with 1,6-hexamethylene diamine to form poly(amide imide) (PAI) salt, and finally synthesized PA6/PAI random copolymers containing an aromatic imide structure by the random copolymerization of ε-caprolactam and PAI salt. The introduction of an aromatic imide structural unit into the PA6 chain could have a great influence on its properties. As the content of PAI increases, the crystallinity (Xc) and melting temperature (Tm) of the PA6/PAI random copolymer gradually decrease, but its glass transition temperature (Tg) increases obviously. When the PAI content is 20 wt%, the copolymer PA6/PAI-20 has the best comprehensive performance and not only has high thermal stabilities but also excellent mechanical properties (high strength, high modulus, and good toughness) and dielectric properties (low dielectric constant and dielectric loss). Moreover, these properties are significantly superior to those of PA6. Such high-performance PA6 random copolymers can provide great promise for the wider applications of PA6 materials.Keywords:polyamide 6;poly(amide imide);random copolymerization
研究领域:
材料科学
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高分子化学
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DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2024
·
IF 7.4
Shijie Tang,Yilin Lu,Qian Xu,Zhiping Chen,Ming Duan,Shenwen Fang
Imine bond is a kind of dynamic covalent bonds, in this paper, hydrophobic chain was introduced into polyethyleneimine (PEI) through imine bond, and a series of hydrophobic modified PEI were synthesized as flocculants for flotation-flocculation treatment of produced water. The hydrophobic modified PEI had much better flotation-flocculation performance than that of PEI. When the concentration was 20 mg/L and treatment was 10 min, the best hydrophobic modified PEI had the turbidity reduction rate of more than 95 %. Especially, in a short period of time, the flocs formed by the hydrophobic modified PEI can have a great decrease in adhesiveness under pH=4 due to the dissociation of imine bonds, which is good for the produced water treatment because the viscous flocs can be effectively processed. In addition, the mechanism study showed that the hydrophobic modified PEI can adsorb on the surfaces of bubbles and oil droplets to improve the collision efficiency and adhesion efficiency between bubbles and oil droplets, thus possessing good flotation-flocculation performance. This paper provides a novel degradable flocculant for produced water treatment.
研究领域:
环境科学
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化学工程
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Yuchen Cui,Xiaolei Cui,Lubomira Tosheva,Chunzheng Wang,Yongming Chai,Zixi Kang,Qiang Gao,Kun Wang,Zhihan Zhang,Hailing Guo,Daohong Xia,Daofeng Sun
Effective separation of CO 2 from CH 4 is crucial for the purification of natural gas, which requires membrane materials with high permeability, selectivity, and stability of under high pressures. In this work, a high CO 2 -affinity MOF-based nanofiller (P in @NH 2 -UiO-66) was prepared and integrated in polyetherimide (PEI) to prepare mixed matrix membranes (MMMs) for enhanced CO 2 /CH 4 separation capabilities. The P in @NH 2 -UiO-66 nanofiller comprised an in situ-formed polyethyleneimine-NH 2 -UiO-66 composite prepared via a one-pot synthesis. The polyethyleneimine was covalently attached to the H 2 BDC-NH 2 ligand allowing for a stronger integration within the PEI matrix. The polyethyleneimine affects the nucleation of MOF, leading to miniaturization of the MOF particles. The smaller-sized filler is beneficial for improved interaction at the filler-matrix interface. The numerous amino functionalities grafted onto the NH 2 -UiO-66 increased the CO 2 adsorption sites, thereby enhancing the affinity for CO 2 . Owing to the improved interaction, the elevated CO 2 attraction, and the inherent properties of the porous NH 2 -UiO-66, the fabricated MMMs preformed superior in separating CO 2 /CH 4 . The 30-P in @NH 2 -UiO-66-PEI membrane (containing 30 wt% nanofiller) exhibited a CO 2 /CH 4 selectivity of 27.7 and a CO 2 permeability of 2498.9 Barrer. The CO 2 permeability was 21 times greater than that of the pristine PEI membrane, and 4 times higher compared to P@NH 2 -UiO-66 MMM with polyethyleneimine modified MOF filler prepared by a traditional wet impregnation method. Additionally, the novel MMM demonstrates excellent separation stability under conditions that mimic industrial settings, demonstrating its potential application for natural gas purification.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 58
·期 20
·2951-2962
·
IF 0
Kai Ma,Guofei Chen,Yonggang Zhang
A series of cross-linked polyimides (PIs) were prepared via two-step solution polycondensation from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) and 2,5-furandicarboxylic acid-based diamines, N,N ′-bis(4-amino-2-(trifluoromethyl)phenyl)furan-2,5-dicarboxamide (TFFDA) and N,N ′-bis(4-aminophenyl)furan-2,5-dicarboxamide ( p -FDDA), followed by thermal crosslinking reaction with bismaleimide. The thermal crosslinking reaction and its mechanism were studied by FTIR spectra and model reaction analysis, which showed Diels–Alder reaction between furan group and maleimide group played a main role in the thermal treatment. The properties of cross-linked PIs were characterized using dynamic mechanical thermal analysis, thermogravimetric analyses, tensile testing, ultraviolet-visible spectra, and wide-angle X-ray diffraction. The cross-linked polyimide film showed improved solvent-resistance, thermal and mechanical properties with T g values of 234–306 o C, tensile strengths of 82–98 MPa and moduli of 2.3–3.0 GPa. Graphical Several cross-linked polyimides (PIs) were prepared via polycondensation of dianhydride and 2,5-furandicarboxylic acid (2,5-FDCA)-based diamines, N,N ′-bis(4-amino-2-(trifluoromethyl)phenyl)furan-2,5-dicarboxamide, and N,N ′-bis(4-aminophenyl)furan-2,5-dicarboxamide, and following thermal crosslinking reaction with bismaleimide. These PIs exhibit outstanding thermal and mechanical properties. The crosslinking network of 2,5-FDCA-based PIs and bismaleimide is constructed for the first time by Diels–Alder reaction. The thermal crosslinking mechanism is also studied in detail using model reaction.
研究领域:
材料科学
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化学工程
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COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Qi Zhao,Xudong Li,Zishang Tian,Hui Ma,Xianglin Hou,Yingxiong Wang,Yuqi Wang
Carbon fiber reinforced bismaleimide resin (CF/BMI) composites are widely used in aerospace field due to their high thermal stability, chemical resistance and excellent mechanical properties . With the large-scale application of CF/BMI composites, it is inevitable to produce a lot of solid wastes, which have a serious impact on the environment, so people have to recycle waste CF/BMI composites. In view of the physical and chemical properties of BMI resin, we developed a green and friendly chemical recovery method of CF/BMI composites by selectively breaking imide bonds for controlled chemical degradation of BMI resin. In 5 wt% NaOH/H 2 O reaction system, the controlled chemical degradation of CF/BMI composites can be realized by selective cleavage of imide bonds, and the 4,4′-Diaminodiphenyl methane (DDM) and 2,2′,2″,2‴-((methylenebis(4,1-phenylene))bis(azanetriyl))tetrasuccinic acid (MBTA) can be recovered, and the carbon fiber (CF) can be recycled at the same time. Under the optimal reaction conditions, the yields of DDM and MBTA reached 6.7 wt% and 27.9 wt% at 180 °C for 8 h, respectively. Meanwhile, CF in CF/BMI composites can be completely recovered, and the tensile strength of recovered carbon fiber (rCF) is about 97.6% of that of virgin carbon fiber (vCF). This work provides a very promising strategy for the recycling of CF/BMI composites. The high value-added CF and chemicals (DDM and MBTA) can be recovered by controlled degradation of CF/BMI composites via selective cleavage of imide bonds.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
DISPLAYS
·
2014
·
IF 1.205
Xia Chen,Tao He,Hongwei Jiang,Biming Wei,Guofei Chen,Xingzhong Fang,Mingliang Jin,Robert A. Hayes,Guofu Zhou,Lingling Shui
We report a screen-printing fabrication process for large area electrowetting display (EWD) devices using polyimide-based materials. The poly(imide siloxane) was selected as hydrophobic insulator layer, and relatively hydrophilic polyimide as grids material. EWD devices that use poly(imide siloxane) as hydrophobic insulator fabricated with conventional methods showed good and reversible electrowetting performance on both single droplet level and device level, which showed its potential application in EWDs. The compatibility of polyimide-based materials (hydrophobic poly(imide siloxane) and hydrophilic polyimide) guarantee the good adhesion between two layers and the capability of printable fabrication. To this end, the hydrophilic grids have been successfully built on hydrophobic layer by screen-printing directly. The resulting EWD devices showed good switch performance and relatively high yield. Compared to conventional method, the polyimide-based materials and method offer the advantages of simple, cheap and fast fabrication, and are especially suitable for large area display fabrication.
研究领域:
材料科学
·
显示技术
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高影响因子
危险品化学品经营许可证（带存储）