POLYMERS FOR ADVANCED TECHNOLOGIES
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2022
·Vol. 33
·期 12
·4290-4301
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IF 3.348
Ping Lyu,Yongbo Hou,Rongzhen Wang,Mingliang Ma,Yan Chen,Qiyang Xing,Yong Ma,Shuang Wang,Yuefeng Wu,Weibo Huang
The flame retardant zinc ferrite@Mg-Al-sodium dodecyl benzene sulfonate layered double hydroxide (ZnFe 2 O 4 @Mg-Al-SDBS LDH) was prepared successfully by simple hydrothermal method and co-precipitation method. ZnFe 2 O 4 nanoparticle was used as the core on which Mg-Al LDH was encapsulated to form a spherical structure with a lamellar intercalation layer. The microstructure, the phase structure, and the thermal properties of flame retardant were characterized in detail. Compared with pure polyurea (PUA), the total heat release (THR), peak heat release rate (PHRR) and smoke factor (SF) of PUA/ZnFe 2 O 4 @Mg-Al-SDBS LDH 3.0 wt% decreased by 17.64%, 20.13%, and 28.42%, respectively. In the combustion process, Mg-Al LDH could generate porous metal oxides (Al 2 O 3 and MgO), and ZnFe 2 O 4 could also be decomposed into ZnO and Fe 2 O 3 . These oxides catalyzed cross-linking of polymer molecules, to promote the formation of a dense char layer, and isolated heat and combustible gases from the underlying material. The improved flame retardant properties of the modified intercalated microspheres could be attributed to catalytic carbonization and physical barrier. Moreover, the mechanical properties of PUA composites were tested by universal tensile testing machine. The results showed that the addition of ZF@MASL flame retardant had little influence on the mechanical properties of PUA composites.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2023
·Vol. 148
·期 11
·4731-4743
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IF 4.4
Kang Furu,Deng Jun,Pang Qingtao,Yuan Chao,Liu Bo,Yi Xin,Li Hang
Silicone foams (SiFs) are high-performance materials but can combust and release choking smoke in a fire. In this paper, the modified microencapsulated Mg/Zn/Al-layered double hydroxide (MLDHs) was prepared by the sol–gel method. Then, the structure and performance of modified MLDHs were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC). Besides, the mechanical properties, flame retardancy, smoke suppression, thermal degradation behavior, morphology and composition of carbon slag of SiFs with modified MLDHs were tested using the universal tensile testing machine, limiting oxygen index (LOI), UL-94 test, cone calorimeter, thermogravimetry, SEM–EDS and XPS. The results indicated that the modified MLDHs could effectively improve the ductility of SiFs. When the addition of modified MLDHs exceeded 20 mass%, SiFs could be improved to UL-94-V0 rating. The PHRR, THR, and TSP of SiFs with 30 mass% modified MLDHs were 56.04%, 46.86%, and 80.49% lower than that of pure SiFs. Furthermore, the decomposition products of modified MLDHs/SiFs composite such as SiO 2 and zinc magnesium aluminum oxide could improve the char formation significantly. The continuous, complete, and dense structure of carbon slag of modified MLDHs/SiFs could effectively block the exchange of heat and gas on the surface of SiFs and reduce the combustion performance of SiFs.
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MATERIALS & DESIGN
·
2023
·
IF 8.4
Wenhui Yao,Jie Qin,Yonghua Chen,Liang Wu,Bin Jiang,Fusheng Pan
A slippery liquid-infused porous surface (SLIPS) was developed, based on MgAl-layered double hydroxide (LDH), in order to improve the corrosion and wear resistance of AZ31 Mg alloys. In particular, different concentrations of SiO 2 nanoparticles were incorporated into the silicone oil to further ameliorate the performances of Mg alloys, which can effectively seal the nanopores constructed by MgAl-LDH. With increasing SiO 2 nanoparticle concentration, the nanosheet microstructure of MgAl-LDH was gradually covered by the hierarchical structure of SiO 2 nanoparticles. The formed composite SiO 2 -SLIPSs exhibited good surface hydrophobicity and superior corrosion and wear resistance. When the concentration of SiO 2 nanoparticle was 10 mg mL −1 , the composite SLIPS showed the best performances, with the lowest corrosion current density of 2.43 × 10 -10 A cm −2 and wear volume of 0.041 mm 3 . The developed composite SLIPSs could find wide applications in effective corrosion and wear protection of Mg alloys in industry.
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MATERIALS TECHNOLOGY
·
2022
·
IF 3.297
Haoxin Li,Guangyu Wu,Qi Liu,Jingyi Wang,Siye Xia,Yingcen Xue,Jiangang Han,Chuansong Duanmu,Yongli Zhu
Wastewater contains dye or pharmaceuticals could imply severe environmental impacts due to their toxicity to ecosystems and, consequently, the generation of human health risks. In this work, the orange peel biochar was prepared through pyrolysis, and then Mg/Al-layered double hydroxide (Mg/Al-LDHs) was grown on the surface of the biochar (BC@Mg/Al-LDHs) by hydrothermal method. The material was characterised by SEM, TEM, XRD, XPS and other techniques. The adsorption performance, adsorption isotherms, kinetics and thermodynamics of BC@Mg/Al-LDHs on methylene blue (MB) or tetracycline hydrochloride (TC) were investigated. The results showed that the maximum adsorption capacity of BC@Mg/Al-LDHs for MB and TC were 75.98 and 29.08 mg/g, respectively. The adsorption equilibrium was reached within 30 minutes, and removal percent was 93.99 and 62.06% for MB and TC, respectively. The obtained results investigate that the prepared BC@Mg/Al-LDHs materials for a broad range of applications in dye and pharmaceuticals separation from the water environment.
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POLYMER
·
2022
·
IF 4.432
Qisong Lin,Feng Gao,Yongjun Wang,Wangyang Lu,Wenxing Chen
Antimony-free poly(ethylene terephthalate) (PET) has been synthesized through polycondensation of p -phthalic acid and ethylene glycol , and then subjected to a viscosity-increasing process by liquid-state polycondensation (LSP). For both of these processes, a novel environmentally benign ethylene glycol-soluble Ti/Mg bimetal (TM) catalyst has been used. The structure of the TM catalyst has been comprehensively characterized and its catalytic activity in the polycondensation reaction has been evaluated and compared with those of other titanium-based catalysts. The results reveal that the TM catalyst is a chelated complex with high catalytic activity for polycondensation to afford PET without significant side reactions. Indeed, the LSP process catalyzed by TM affords a PET product with high intrinsic viscosity suitable for industrial yarn production (1.08 dL/g) within 60 min, and that exhibits higher thermostability with increasing intrinsic viscosity. Finally, the kinetics of the TM-catalyzed polycondensation has been probed based on the variation of intrinsic viscosity with increasing polycondensation time.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
·
IF 5.518
Dongbo Zhu,Jihui Wang,Wenbin Hu
Hydroxyapatite (HA) bioactive film is a standard surface modification method for biodegradable Mg alloys . However, the corrosion resistance of HA film prepared before was mediocre, and the preparation process was complicated. In this study, hydroxyapatite film was prepared for the first time on layered double hydroxides (LDHs) coated Mg alloy by hydrothermal method . The structure and composition of LDHs and HA films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and immersion behavior of the films in simulated body fluid (SBF) were investigated by using potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) techniques. The effects of different pH and calcium to phosphorus molar ratios (Ca/P ratios) of HA hydrothermal solution were investigated. The experimental results show that HA films appear in petal-like, filamentous and flower-like. The corrosion resistance of the film first increases and then decreases with the pH from weak acid to alkaline. With the increase of the Ca/P ratio, the film is gradually denser, and the protective effect is enhanced. The immersion test results show that after 7 days of immersion, the impedance modulus of the composite film is about 5 × 10 3 Ω·cm 2 , which is ten times higher than the single LDHs film. The effects of the pH and Ca/P ratio of the HA hydrothermal solution on the preparation of HA film are simply explained by thermodynamic theory. The Mg-LDHs-HA composite film provide a corrosion protection barrier for Mg substrate and HA film is biologically active. The barrier effect and the mineralization behavior provide a better corrosion protection for Mg substrate.
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Frontiers in Chemistry
·
2022
·
IF 5.545
Hu Yanru,Zhang Gengrui,Liu Lele,Chi ZiXin,Wang Shuai,Lin Jingdong,Xiong Haifeng,Wan Shaolong
The thermocatalytic conversion of hexose into valuable chemicals such as methyl lactate under mild conditions is very appealing. Here, we report that Mo, Mg co-modified Sn-β catalyst can effectively catalyze the transformation of glucose and fructose into alkyl lactate at moderate temperatures. A maximum yield of around 35% of methyl lactate was achieved from the conversion of glucose in methanol at 100°C over Sn-β catalyst modified with 3 wt% Mo and 0.5 wt% Mg. However, up to 82.8% yield of ethyl lactate was obtained in the case of fructose in ethanol upon the same catalytic condition, suggesting a significant solvent effect. The Mo species plays a key role to enable the retro-aldol condensation of fructose, in which the competing side reactions are significantly suppressed with the assistance of neighboring Mg species probably through a synergetic effect of Lewis acid-base.
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PubMed
高影响因子
CHEMICAL PHYSICS LETTERS
·
2021
·
IF 2.328
Guanfeng Tian,Youqing Wu,Shiyong Wu,Sheng Huang,Jinsheng Gao
In 2 O 3 , MnO/In 2 O 3 , and MgO/In 2 O 3 catalysts are synthesized by the co-precipitation method and investigated for CO 2 hydrogenation to methanol. The introduction of Mn and Mg oxides dramatically enhances the CO 2 adsorption capacity of In 2 O 3 . The changing trend of methanol selectivity is consistent with the CO 2 adsorption capacity. MnO/In 2 O 3 and MgO/In 2 O 3 catalysts show higher methanol selectivity compared with that of In 2 O 3 .
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Materials Today Chemistry
·
2021
·
IF 8.301
H.J. Gao,S.F. Wang,L.M. Fang,G.A. Sun,X.P. Chen,S.N. Tang,H. Yang,G.Z. Sun,D.F. Li
Nanostructured spinel-type M(M = Mg, Co, Zn)Cr 2 O 4 oxides with novel adsorbents for aqueous Congo red removal were synthesized by a polyacrylamide gel method and studied for their phase structure, microstructure, adsorption performance, and multiferroic behavior. The phase structure and purity analysis revealed that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr 2 O 4 oxides presented a spinel-type cubic structure, and the formation of a secondary phase such as Cr 2 O 3 , MgO , ZnO, or Co 3 O 4 was not observed. The microstructure characterization confirmed that the spinel-type MCr 2 O 4 oxides grew from fine spherical particles to large rhomboid particles. Adsorption experiments of spinel-type MCr 2 O 4 oxides for adsorption of Congo red dye were fitted well with the pseudo-second-order kinetics. The adsorption capacity of the ZnCr 2 O 4 oxide (44.038 mg/g, pH 7, temperature 28 °C, initial dye concentration 30 mg/L) was found to be higher than that of MgCr 2 O 4 oxide (43.592 mg/g, pH 7, temperature 28 °C) and CoCr 2 O 4 oxide (28.718 mg/g, pH 7, temperature 28 °C). The effects of initial adsorbent concentration, initial dye concentration, pH, and temperature between the ZnCr 2 O 4 oxide and Congo red dye at which optimal removal occurs, were performed. The thermodynamic studies confirmed that a high temperature favors the adsorption of Congo red dye onto ZnCr 2 O 4 oxide studied. The nanostructured spinel-type M(M = Mg, Co, Zn)Cr 2 O 4 oxides that exhibited high adsorption performance for adsorption of Congo red dye can be ascribed to the synergistic effect of electrostatic interaction , pore filling, and ion exchange. The present work suggested that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr 2 O 4 oxides have excellent adsorption performance and multiferroic behavior, which shows potential applications for removal of the Congo red dye from wastewater, magnetic memory recording media, magnetic sensor, energy collection and conversion device, and read/write memory.
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APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Yankai Liu,Ruinian Zhou,Jianyu Qu,Feng Han,Shuai Zhang,Xingliang Xu
Upgrading carbon dioxide (CO 2 ) into valuable products is a highly promising strategy of artificial carbon cycle. In this study, a series of in situ reduced CuMgAl layered double hydroxides (R-CuMgAl-LDHs) composites were synthesized, in which Cu nanoparticles were effectively dispersed and anchored on MgAl-LDHs with formation of Cu + and Cu 0 species. The optimized R-Cu 1.5 Mg 1.5 Al 1 -LDH exhibited excellent catalytic performance for the carboxylative cyclization of 2-methyl-3-butyn-2-ol with CO 2 (turnover number of 243) under mild conditions. The layered structure of LDH stabilized the active Cu species with high dispersion, enhancing the catalytic efficiency of this carboxylative cyclization reaction. Simultaneously, the dual-activation of both CO 2 and propargylic alcohol by Cu 0 /Cu + species generated on the surface of LDH contributed significantly to the catalytic efficiency enhancement. Furthermore, R-Cu 1.5 Mg 1.5 Al 1 -LDH catalyzed the reaction of a wide range of terminal or internal propargyl alcohols with CO 2 , yielding various functionalized α-alkylene cyclic carbonates. Finally, a reasonable reaction mechanism was put forward according to the comprehensive analysis.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Mewin Vincent,Venkata Sai Avvaru,Maciej Haranczyk,Vinodkumar Etacheri
Despite of their inexpensive and sustainable characteristics, practical application of Mg-Na hybrid batteries are limited due to the lack of high performance dual-ion compatible cathode materials. This is mainly due to the increased size of Na-ions and improved electrostatic repulsion resulting from the high charge density of Mg-ions. Herein, we report for the first time a fast charging and ultralong-life Mg-Na hybrid battery based on an extremely pseudocapacitive hierarchical bronze TiO 2 (TiO 2 -B) nanosheet cathode. This two dimensional cathode exhibited outstanding pseudocapacitance (up to 94%), specific capacities (195 mAh/g @ 25 mA/g), rate performance (140 mAh/g @ 1A/g), cycling stability (∼76% after 6000 cycles @ 1A/g), coulombic efficiency (∼100%) and fast-charging (∼8 min). These performances are vastly superior to the previously reported metal oxide type Mg-Na hybrid battery cathodes. Mechanistic investigations revealed Mg-Na dual-ion intercalation pseudocapacitance with no significant structural changes. Exceptional electrochemical performance of the TiO 2 -B nanosheet cathode is credited to the dominant pseudocapacitive Mg-Na dual-ion diffusion through the nanointerfaces resulting from the hierarchical microstructure of TiO 2 -B nanosheets. High surface area, ultrathin nature and mesoporous structure are also contributed as secondary factors by facilitating superior contact with the electrolyte solution. The demonstrated method of nanointerfaces induced pseudocapacitive Mg-Na dual-ion intercalation provides new opportunities for the development of high-performance Mg-Na hybrid batteries.
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Materials Today Communications
·
2021
·
IF 3.383
Yanqing Xue,Bo Li,Xinliang Wang,Xinlei Li,Han Zhang,Qitang Hao
Agglomeration behavior of TiB 2 particles in 5%TiB 2 /Al-4.5%Cu composites (all compositions are in wt.% unless otherwise specified) is studied by adding different content of Mg to improve its strength and ductility, a widely used in-situ molten salt reaction process is used to produce the composites. The results show that addition of Mg could not only significantly segregate TiB 2 particles but also further refine the α-Al grains and then improve the mechanical properties of the composites on the basis of TiB 2 particles. Here, 0.5% Mg is considered the optimum mass fraction for dispersion, refinement, and modification of particles based on the results of investigation. The yield strength (YS), ultimate tensile strength (UTS), elastic Young’s modulus (EM), and Vicker’s hardness (VHN) of the composites in T6 heat treatment are increased to 375 MPa, 486 MPa, 88 GPa, and 167 HV - an improvement of 21.8%, 16.5%, 20.9%, and 9.4%, respectively, versus the original TiB 2 /Al-4.5%Cu composite (308 MPa, 417 MPa, 63 GPa, and 153 HV). The elongation of the composite is improved by 20.9%. These merits are mainly attributed to addition of Mg, which increases the surface-spread coefficient of TiB 2 particles by reducing the surface tension of the Al melt, thereby improving the wettability .
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