POLYMER COMPOSITES
·
2024
·
IF 4.8
Wenqi Zou,Kaiqiang Luo,Jun Xu,Munan Qiu,Jing Tian,Zhanpeng Wu,Baohua Guo
In this study, the challenges of brittleness and flammability in Polyamide 6/glass fiber (PA6/GF) composites, which are crucial for heat-resistant and stress-bearing structural parts, are addressed. Polyphosphazene (PZ) elastomers, known for their exceptional flame-retardant properties, are introduced to enhance the robustness and safety of these composites. Specifically, poly(diaryloxy)phosphazene (PDAP) and poly(difluoroalkoxy)phosphazene (PDFP) are utilized, both contributing to the improved toughness and flame resistance of the PA6/GF composites. Experimental results show that PDAP mainly played the role of solid-phase flame retardant, while PDFP mainly acted the role of gas-phase flame retardant. For PA/PZs composites without adding GF, PDFP plays a more efficient flame retardant effect than PDAP. By introducing 15 Vol% of PDFP, the limiting oxygen index (LOI) of the composite reached 26.1%, while the notched impact strength increased by 297%. For PA/PZs/GF composites, PDAP plays a better flame retardant role than PDFP. Under the action of 30 vol% GF and 15 vol% PDAP, the LOI of PA6/PDAP/GF composite reached 26.8%, and the notch impact strength improved to 18.7 kJ/m 2 , which is 165% higher than that of PA6/GF, and the UL-94 test reaches V-0 level. The findings of the study highlight the potential of PDAP and PDFP to act as dual-function modifiers. These modifiers can considerably ameliorate both the impact resistance and flame retardancy of PA6 and PA6/GF composites. Such dual enhancement surpasses the typical trade-offs seen in conventional composites, indicating a constructive direction for future material innovation. Highlights Polyphosphazenes simultaneously enhance PA6's toughness & flame resistance. Distinct flame retardant mechanisms found in PDAP and PDFP. GF presence alters PDAP and PDFP's flame retardant efficacy. PDAP shows superior flame resistance in GF-reinforced PA6 composites. Without GF, PDFP outperforms PDAP in enhancing flame retardancy.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Wenji Zheng,Yuehu Guo,Ziheng Li,Xuehua Ruan,Xiaobin Jiang,Tiantian Li,Xiangcun Li,Yan Dai,Gaohong He
Polymer-supported MOFs membranes with high separation performances show great potentials in industrial purification of H 2 . The key to growing defect-free and adherent MOFs layers on polymer substrates is the abundant and uniformly distributed nucleation sites on the surface of polymer substrates. Therefore, in this work, a mixed-matrix polyacrylonitrile (PAN) substrate with ZIF-8-rich seed layer (ZS-PAN) was constructed by gravity induced deposition and gradient distribution of ZIF-8 before phase inversion, then under the assistance of Tannic acid (TA), the dense and defect-free ZIF-8 membrane on flexible polymer substrate was fabricated followed by the secondary growth of ZIF-8. The EDS and SEM results of the membrane cross-section confirm the gradient distribution of ZIF-8 seeds, and the resultant membranes are defect-free. The H 2 permeance of TA-ZIF-8/ZS-PAN membrane is 953.66 GPU, and the H 2 /CO 2 selectivity is 12.09, which is 80.17 % higher than that of ZIF-8/ZS-PAN membrane without TA, exceeding the Robeson upper bound in 2008. This improved H 2 separation performance is derived from the following reasons. First, gravity-induced ZIF-8 seed deposition constructs a ZIF-8-rich seed layer on the mixed-matrix polymer substrate, which increases the nucleation sites. Second, the introduction of TA during the secondary growth process further increases the nucleation sites by hydroxyl-chelated zinc ions, both of which contribute to the dense ZIF-8 membrane. At the same time, the hydroxyl group in TA is CO 2 -philic, which can delay CO 2 permeation and improve the H 2 /CO 2 separation performance by physically adsorbing CO 2 . The proposed mixed-matrix substrate by gravity induced deposition of MOFs provides a novel strategy for constructing defect-free and flexible MOFs membrane.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 32
·48937
·
IF 2.52
Kuiyong Chen,Yue Liu,Yongjian Hu,Meiyu Yuan,Xiuwen Zheng,Xiaobin Huang
Amino-functionalized highly crosslinked organic–inorganic hybrid polyphosphazene microspheres were prepared via a one-pot polycondensation method and served as a fluorescent sensor for the detection of Fe 3+ in solution. With the introduction of p -phenylenediamine unites, the polyphosphazene microspheres could be endowed with fluorescent property and abundant active amino groups on the surface. The microspheres were further used as the fluorescent sensor for the detection of Fe 3+ . Fluorescence study showed high sensing sensitivity and selectivity of the microspheres, and the limit of detection was determined as 0.076 μM for Fe 3+ . Active amino groups on the surface could efficiently improve the detection sensitivity of Fe 3+ . Moreover, highly crosslinked organic–inorganic hybrid structure was beneficial to the photostability and thermostability, enabled the microspheres to be possible for constructing practicable sensors. This work is expected to inspire the design of advanced polyphosphazene-based fluorescent sensors for applications in analytical detection. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48937.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Zhenguo Dou,Ying Wang,Wenhui Fang,Chenglin Sun,Zhiwei Men
Raman spectra of acetonitrile (CH 3 CN)–sodium perchlorate (NaClO 4 ) mixture solutions at different concentrations and temperatures have been studied. It was suggested that the shifts and intensities of Raman modes of CH 3 CN varied significantly due a novel Fermi resonance (FR) was formed between the ν 2 ′ and ( ν 3 + ν 4 )′ bands of CH 3 CN-Na + complex. The phase transition underwent from the liquid to solid phase β at 223 K, and from β to α at 213 K, which were induced by the strong cationic-molecule interaction. In addition, the impact of Na + on FR was discussed by the FR parameters at different concentrations and temperatures.
研究领域:
物理化学
·
分子光谱学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2020
·Vol. 12
·期 11
·2763
·
IF 3.426
Munir Hussain,Sohail Yasin,Hafeezullah Memon,Zhiyun Li,Xinpeng Fan,Muhammad Adnan Akram,Wanjie Wang,Yihu Song,Qiang Zheng
In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.Keywords:nitrile butadiene rubber;rheology;ionic liquids;tensile properties
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 12
·3434
·
IF 5.076
Haodong Zhao,Yali He,Zhihua Wang,Yanbao Zhao,Lei Sun
Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high permeability. Herein, a novel, simple and low-cost method has been proposed for the separation of emulsion containing surfactants. Polyacrylonitrile (PAN) nanofibers were prepared via electrospinning and then coated by polydopamine (PDA) by using self-polymerization reactions in aqueous solutions. The morphology, structure and oil-in-water emulsion separation properties of the as-prepared PDA@PAN nanofibrous membrane were tested. The results show that PDA@PAN nanofibrous membrane has superhydrophilicity and almost no adhesion to crude oil in water, which exhibits excellent oil–water separation ability. The permeability and separation efficiency of n-hexane/water emulsion are up to 1570 Lm−2h−1bar−1and 96.1%, respectively. Furthermore, after 10 cycles of separation, the permeability and separation efficiency values do not decrease significantly, indicating its good recycling performance. This research develops a new method for preparing oil–water separation membrane, which can be used for efficient oil-in-water emulsion separation.Keywords:polyacrylonitrile;electrospinning;nanofibrous membrane;emulsion separation
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2021
·
IF 4.354
Hao Song,Yao Xiao,Zhuohua Zhang,Wanjin Xiong,Ren Wang,Liangcheng Guo,Taigang Zhou
A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine–BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 48
·7427-7435
·
IF 5.687
Nafeesa Mushtaq,Guofei Chen,Lala Rukh Sidra,Yang Liu,Xingzhong Fang
Two novel series of highly organosoluble and curable polyimides containing pendant nitrile groups PI (a–d) and phthalonitrile-terminated polyimides PN-PI (a–d) were prepared by solution polycondensation of isomeric bis(chlorophthalimides)s and 2,6-dichlorobenzonitrile with 4,4′-thiobisbenzenethiol. The inherent viscosities of these copolymers were in the range of 0.37–0.59 dL g−1 in N-methyl-2-pyrrolidone (NMP) at 30 °C. The phthalonitrile and pendant nitrile groups in isomeric poly(thioether-ether-imide)s were thermally crosslinked without a catalyst through thermal curing up to 280–360 °C, which led to the transformation from thermoplastic polymers to thermosetting polymers. All PIs before and after crosslinking were characterised by gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. PN-PI (a–d) and PI (a–d) were found to be highly soluble in some solvents, such as chloroform, dimethylacetamide, m-cresol, dimethlyformamide and N-methyl-2-pyrrolidone, while the crosslinked polymers were insoluble in all tested solvents. The crosslinking results of pendant nitrile and terminal phthalonitrile groups are also compared. Both series of PIs showed high thermal stability based on 5% weight loss temperature (T5%) in the range of 471–509 °C and increased up to 35 °C after thermal curing. Polyimides showed high glass transition temperatures (Tgs) ranging from 191–213 °C as determined by DSC, but no detectable Tg was observed after thermal heating, indicating the crosslinked structure of PIs. The mechanical properties also enhanced after the crosslinking of the copolymers. The tensile modulus and strength of the cured PI films were in the range of 3.3–4.7 GPa and 68–122 MPa, respectively, which were up to 62% and 35% higher than the uncured films.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2023
·
IF 13.1
Ziyue Ling,Chunji Jiang,Xianda Liu,Yupei Li,Weifeng Zhao,Changsheng Zhao
Endotoxins (LPS) are components of the cell wall of Gram-negative bacteria that are released when bacterial cell membrane is destroyed, the bacteria and the released LPS have led to serious diseases such as sepsis and septic shock. Histidine functionalized adsorbents have been used to remove LPS, however, the present hemoperfusion adsorbents have drawbacks such as inadequate LPS adsorption capability, high cost of raw material, and so on. Inspired by the structure of histidine and incorporated antibacterial molecules, we synthesize allylamine-modified polyacrylonitrile (PAD)/poly (imidazolium bromide) (PMIBr) composite (PAI) microspheres as hemoperfusion adsorbents. The PAI microspheres show excellent antibacterial ability with high killing efficiency of 98.8% against S. aureus and 95.4% against E. coli . In addition, the adsorption capacity of the microspheres for LPS in PBS is 433.5 EU/g within 3 h, and the LPS concentration could also be reduced from 7.34 EU/mL to below 0.5 EU/mL in the plasma environment. The PAI microspheres exhibit outstanding blood compatibility, antibacterial property and endotoxin removal capability, which have great potential in the treatment of sepsis patients.
研究领域:
医学
·
生物材料学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2024
·
IF 2.1
Huijie Yan,Yuhang Jiao,Bingrui Jin,Huixuan Zhang,Zhongyu Fu,Shiling Jia,Yunjiao Deng
Aqueous precipitation polymerization is commonly used in the industry due to its efficient heat dissipation, reaction stability and production flexibility. However, its mechanisms and kinetics are still partially unclear. The ammonium persulfate-ammonium sulfite monohydrate (APS-AS) initiated aqueous phase precipitation polymerization of acrylonitrile (AN) at low concentration was deeply investigated, with the APS initiation system as a control. The apparent kinetic equations for the APS and APS-AS initiation systems were determined to be Rp= K[AN]1.706[(NH4)2S2O8]0.704 and Rp= K[AN]3[(NH4)2S2O8]0.704[(NH4)2S2O3]−1.055, respectively. Monitoring AN distribution in the aqueous and polyacrylonitrile (PAN) phases revealed a rapid transition of the reaction site from the aqueous phase to the PAN phase following polymer precipitation. Zeta potential and primary particle number exposed that the nucleation site disparities between initiation systems led to different predominant factors affecting the polymerization rate. The change in molecular weight during polymerization had a maximum due to its dependence on the monomer concentration. The crystallinity of the product initially increased during polymerization, then decreased and eventually stabilized. Scanning electron microscopy (SEM) revealed that the diameter of the internal particles was larger, while the surface particles were smaller after coagulation. These findings offer crucial insights for optimizing aqueous precipitation polymerization and PAN particle property control.
研究领域:
高分子化学
·
化学反应工程
·
材料科学
·
工业聚合过程
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2017
·Vol. 24
·期 4
·1-7
·
IF 1.615
Li Hu,Zhou Zhen,Liu Jingcheng,Zheng Xiangfei,Xu Wenjia,Ji Changwei,Shi Weidong,Liu Ren,Liu Xiaoya
Hexakis(4-formylphenoxy) cyclotriphosphazene (HAPCP), substitution reaction product of hexachlorotriphosphazene (HCTP) with p-hydroxybenzaldehyde, was reduced by sodium borohydride to afford hexakis[4-(hydroxymethyl) phenoxyl] cyclotriphosphazene (HHPCP). The hydroxyl group of this compound was then protected by the reaction with di-tert-butyl dicarbonate ester (DBDC) in the presence of 4-dimethylaminopyridine (DMAP) as catalyst to give t-butyloxy carbonyl (tBOC) protected HHPCP. Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1 H NMR) were employed to characterize the chemical structure, indicating that the synthesis was successful. Thermal behavior was characterized by thermogravimetric analysis (TGA), the results showed that the initial thermal decomposition temperature occurred at approximately 170 °C, X-ray diffraction analysis (XRD) results showed that the tBOC protected HHPCP derivatives had amorphous form, and performed excellent film-forming property. Upon irradiation to 365 nm exposure, the photoacid generated proton H + , which can catalyze the deprotection of acid labile tBOC group. This type of novel molecular glass photoresist based on hexachlorotriphosphazene showed high sensitivity, making it possible to fabricate 1 μm line and space pattern under i-line exposure.
研究领域:
材料科学
·
化学
·
半导体制造
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2024
·Vol. 171
·期 8
·085501
·
IF 3.1
Yinghong Zhu,Minling Zhou,Zhanbang Ge,Yufeng Jiao,Menghui Wang,Wujin Peng
An efficient and transition-metal-free synthesis strategy of aromatic nitriles from corresponding aldehydes with H2SO4(NH2OH)2 as the nitrogen source and Cl−/ClO− as the redox mediator was developed. The redox Cl−/ClO− showed electrochemical reversibility in acidic condition. The possible mechanism involving the transformation of Cl−, the generation and electrochemical reduction of nitrile oxides based on the results of cyclic voltammetry and constant current electrolysis was proposed.
研究领域:
有机化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）