POLYMER DEGRADATION AND STABILITY
·
2017
·
IF 3.386
Mei Wang,Xianghai Song,Jianchun Jiang,Jianling Xia,Mei Li
N-(2-amino ethyl) tung maleamic acid (AETMA) and N-(2-amino phenyl) tung maleamic acid (APTMA) were prepared from the ammonolysis of ethidene diamine (ED) and p-phenylenediamine (PPD) respectively with tung-maleic anhydride (TMA). Then LAETMA-Ca, LAPTMA-Ca, LABTMA-Zn and LAPTMA-Zn were separately synthesized through a one-step method and characterized by Fourier transform infrared spectrometry (FTIR), 1 H nuclear magnetic resonance (NMR) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). LAETMA-Ca/LAETMA-Zn and LAPTMA-Ca/LAPTMA-Zn were both used as thermal stabilizers of polyvinyl chloride (PVC) and investigated using Congo red test, thermal aging test, ultraviolet-visible spectrometry, thermogravimetric analysis (TGA), TGA-FTIR, and TGA–mass spectrometry (MS). Their stabilizing efficiencies were compared with other common stabilizers. Dynamic mechanical of the PVC compounds were also studied. The LAPTMA-Ca/LAPTMA-Zn exhibits excellent long-term stability and better plasticization performance for PVC than other stabilizers, and thus can partly replace di(2-ethylhexyl) terephthalate in the processing of PVC. The mechanism underlying the stabilizing action of LAPTMA-Ca/LAPTMA-Zn is suggested.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Coatings Technology and Research
·
2025
·
IF 2.8
Tang Baoling,He Ziyu
The commonly used dispersants for graphene dispersions reduce the conductivity of the composite. In this work, a dispersant with an amphiphilic structure, CA-g-PANI, has been designed and synthesized. The dispersant grafts citric acid (CA) onto polyaniline via an amide reaction, which gives CA-g-PANI the hydrophilic groups (carboxyl groups) and the benzene ring structures that can be π–π conjugated with graphene, and it can improve the dispersion properties of graphene; CA-g-PANI contains the polyaniline structure, which is electrically conductive and enhances the electrical conductivity of graphene dispersions. The molecular structure and properties of the dispersant were systematically characterized through FTIR spectra, UV absorption spectra, and other methods. The graphene-based composites were prepared by screen printing method, and the dispersibility and resistivity of CA-g-PANI were compared with gum arabic and alkali lignin (natural dispersants). Graphene concentration reached up to 30 mg/mL in the presence of CA-g-PANI at the weight ratio of 1:0.03 (CA-g-PANI: graphene). CA-g-PANI also exhibited good performance for stabilizing graphene (stable for 6 days), with an electrical conductivity of up to 917.43 S/m. In the study, it was shown that CA-g-PANI as a graphene dispersant improved the conductivity of graphene dispersions while enhancing the dispersing properties of graphene.
研究领域:
材料科学
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化学工程
·
纳米技术
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DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2015
·Vol. 117
·期 1
·239-251
·
IF 1.17
Geng Gaoli,Wei Ruiping,Liang Ting,Zhou Minghao,Xiao Guomin
A series of Cu–Ca–Al hydrotalcite derived catalysts were prepared by the co-precipitation method. Their catalytic activities were evaluated in the hydrogenolysis of glycerol. The catalysts were characterized by XRD, SEM, TEM, ICP, NH 3 -TPD, CO 2 -TPD and H 2 -TPR. It was observed that the incorporation of calcium and aluminum in the Cu–Ca–Al catalyst improved the conversion of glycerol and promoted the generation of 1,3-PDO. This is due to the appropriate acidity and basicity of the catalyst, which is confirmed by NH 3 -TPD and CO 2 -TPD. The conversion of glycerol over the catalyst with a Cu–Ca–Al mole ratio of 1:3:5 was up to 73.2 % with 42.6 % selectivity to 1,2-PDO and 9.1 % selectivity to 1,3-PDO. Effects of the reaction time, reaction temperature and initial hydrogen pressure on the conversion and selectivity were systematically investigated.
研究领域:
化学工程
·
催化材料科学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2013
·
IF 1.789
Lin Gan,Zhi-Yong Mao,Yi-Fei Wang,Fang-Fang Xu,Ying-Chun Zhu,Qing Huang,Xue-Jian Liu
Cerium-doped Ca–α-SiAlON phosphors with Ca n −1.5 x Si 12− m − n Al m + n O n N 16− n :Ce x ( m =2 n , 0.8≤ m ≤2.4, and 0.02≤ x ≤0.40) nominal compositions have been synthesized by gas pressure sintering (GPS). The photoluminescence (PL) properties were studied in relation to phase composition, particle morphology , and microstructure. Continuous addition of Ce rare-earth (RE) could enhance the emission intensity of phosphors, which was partially attributed to the formation of increased amount of planar defects where dense doping of Ce ions is achieved. Such enhancement could hold up to x =0.32, above which the emission intensity fell slightly due to the formation of more secondary phases and a surface glassy phase rather than concentration quenching. Finally, possible ways to improve the luminescence properties of Ce-doped α-SiAlON phosphors were discussed through tailoring the composition and microstructure.
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2022
·Vol. 24
·期 12
·1-13
·
IF 2.533
Wang Yu,Li Yao,Yang Xiao-Hui,Zhang Guo-Hua
Nano-Zirconium diboride (ZrB 2 ) powder was vital raw material for manufacturing ultra-high temperature ceramics (UHTCs) and C/C composite materials, which were widely used in extreme environment. In this paper, a convenient way of synthesizing nano-ZrB 2 powder was proposed. Firstly, the precursor consisting of ultrafine-ZrC and C was obtained via vacuum carbothermal reduction of nano-ZrO 2 . And then, the carbothermal reduction product was boronized by B 4 C in Ca melt. In boronation process, Ca melt would play a key role as decarburizer. By boronation reaction at 1373 K and 1473 K, cauliflower-shaped ZrB 2 particle and smooth polyhedral ZrB 2 particle were obtained, respectively. XRD and BET analyses showed that the grain sizes and BET-equivalent particle diameters of these two products were less than 100 nm.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Zhi Deng,Jintao Gu,Yuyu Li,Shuai Li,Jian Peng,Xiang Li,Jiahuan Luo,Yangyang Huang,Chun Fang,Qing Li,Jiantao Han,Yunhui Huang,Yusheng Zhao
Na 2 Zn 2 TeO 6 is a potential sodium solid electrolyte of all-solid-state sodium-ion batteries . In this work, Na + ion conductivity and electrochemical performance of layered Ca-doped Na 2 Zn 2- x Ca x TeO 6 ( x = 0–0.05) (NZTO-C x ) electrolytes have been investigated. The highest conductivity has been achieved 7.54 × 10 −4 S cm −1 in NZTO-Cx at x = 0.02, at room temperature due to grain-boundary modification and interlayer-interface elimination. Meanwhile, chemical stability with metallic Na anode and electrochemical window of NZTO-C x are improved by Ca doping. Furthermore, the cycle stability of Na 3 V 2 (PO 4 ) 3 /NZTO-C x /Na solid-state batteries have been successfully increased by Ca doping. These advantages highly demonstrate good potential application prospect of NZTO-C x in all-solid-state sodium-ion batteries.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Chaoliang Wang,Xiaoyang Zhao,Yongjun Li,Dehu Yang,Fuyang Liu,Feng Liu,Li Li,Ping Ke
A series of simple and low-cost Ca-doped g-C 3 N 4 (Ca/CN-X) photocatalysts were fabricated through a two-step calcination method for photodegradation of methylene blue (MB) simulated dyeing wastewater. The results showed that the photodegradation efficiency of Ca/CN-15 % on MB removal under visible light was 97.7 %, and the degradation rate constant was 4 times that of CN, showing the best photocatalytic performance. This was attributed to the fact that the doping of Ca expanded the absorption band edge, reduced the band gap, and suppressed the photogenerated electron-hole recombination, thereby increasing its corresponding photocatalytic activity. A possible photodegradation mechanism was explored, and it was found that h + was the main active species during the process. The above indicated that Ca/CN-X can be regarded as a promising catalyst for dyeing wastewater treatment.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 53
·33626-33636
·
IF 3.361
Leliang Wu,Yiting Lin,Yimin Zhang,Peng Wang,Mingjun Ding,Minghua Nie,Caixia Yan,Shiyao Chen
Alkaline substances could activate peroxymonosulfate (PMS) for the removal of organic pollutants, but relatively high alkali consumption is generally required, which can cause too high pH of the solution after the reaction and lead to secondary pollution. Within this study, PMS activated by a relatively low dosage of Ca(OH)2 (1 mM) exhibited excellent efficiency in the removal of bisphenol S (BPS). The pH of the solution declined to almost neutral (pH = 8.2) during the reaction period and conformed to the direct emission standards (pH = 6–9). In a typical case, BPS was completely degraded within 240 min and followed the kinetics of pseudo-first-order. The degradation efficiency of BPS depended on the operating parameters, such as the Ca(OH)2, PMS and BPS dosages, initial solution pH, reaction temperature, co-existing anions, humic acid (HA), and water matrices. Quenching experiments were performed to verify that singlet oxygen (1O2) and superoxide radicals (O2˙−) were the predominant ROS. Degradation of BPS has been significantly accelerated as the temperature increased. Furthermore, degradation of BPS could be maintained at a high level across a broad range of pH values (5.3–11.15). The SO4−, NO3− did not significantly impact the degradation of BPS, however, both HCO3− and HA inhibited oxidation of BPS by the Ca(OH)2/PMS system, and Cl− had a dual-edged sword effect on BPS degradation. In addition, based on the 4 identified intermediates, 3 pathways of BPS degradation were proposed. The degradation of BPS was lower in domestic wastewater compared to other naturals waters and ultrapure; nevertheless, up to 75.86%, 77.94% and 81.48% of BPS was degraded in domestic wastewater, Yaohu Lake water and Poyang Lake water, respectively. Finally, phenolic chemicals and antibiotics, including bisphenol A, norfloxacin, lomefloxacin hydrochloride, and sulfadiazine could also be efficiently removed via the Ca(OH)2/PMS system.
研究领域:
环境科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
Green Processing and Synthesis
·
2022
·Vol. 11
·期 1
·204-217
·
IF 3.97
Tao Liu,Lirui Mao,Facun Jiao,Chengli Wu,Mingdong Zheng,Hanxu Li
Flux, able to improve the ash fusibility, usually contains catalytic metal compounds. Unfortunately, the quantitative analysis of synergistic catalysis effects between different fluxing agents on coal gasification has not been investigated thoroughly. In this study, the effect of the kinds and content of Na/Ca-based fluxes on char gasification was investigated in thermogravimetry analyzer (TGA). The synergistic catalysis effects and mechanism between the two kinds of fluxes were also studied. Finally, based on the TGA tests, the kinetics models for char gasification with flux addition were developed. The results showed that all the four Na-based fluxes could increase the char reactivity. Na 2 CO 3 , which afforded the best activity, could increase the reactivity by 5.3 times when the content was 5%. The five Ca-based fluxes had a weaker catalysis effect compared with Na-based fluxes. CaCl 2 , exhibiting the best activity among the five Ca-based fluxes, could increase the reactivity by 2.3 times when the content was 5%. For composite fluxes, Na 2 CO 3 –CaO and Na 2 CO 3 –CaCO 3 had a remarkable synergistic effect, whereas others had less effect. Na 2 CO 3 could inhibit the aggregation of Ca, which might cause the synergistic effects between Na and Ca fluxes. The random pore model was more suitable to describe the catalytic gasification process.
研究领域:
能源科学
·
化学工程
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产品关联
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2020
·Vol. 37
·期 5
·776-783
·
IF 2.69
Liu Xinghao,Hu Shuheng,Xu Di,Shao Dadong
Uranium (VI), as a toxic contaminant, is a potential detriment to human health and environmental safety. In this experiment, carboxymethyl cellulose/Ca-rectorite composite material (Ca-REC/CMC) was prepared by crosslinking reaction to remove U(VI) from the liquid. The crystal structure was detected by X-ray diffraction (XRD) and surface structure and morphology of the materials were investigated by scanning electron microscopy (SEM). The surface functional groups of prepared materials were detected by Fourier transform infrared spectroscopy (FT-IR). The adsorption capacity of Ca-REC/CMC improved obviously after being modified by CMC. The adsorption capacity of Ca-REC/CMC was closely related to ionic strength and pH. According to thermodynamic parameter calculation, the adsorption process was endothermic and spontaneous. Adsorption isotherms could be depicted perfectly by the Langmuir model. Ca-REC/CMC maintained stability and regeneration after recycling six times. The adsorption mechanism, including electrostatic interactions and ionic interaction, was investigated by the X-ray photoelectron spectroscopy (XPS). Ca-REC/CMC is considered as remarkable potential material for removing U(VI) from the water environment.
研究领域:
环境科学
·
材料科学
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产品关联
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2022
·
IF 4.966
Xiao Li Li,Peng Liu,Bin Chu,Jin Mei He,Zhen Wang,Song Wang,Chang Sheng Chen,Xiao Hong Ge,Hui Li,Wei Qiang Liu
Myocardial infarction (MI) is a common heart emergency that potentially causes death. Injectable hydrogels with excellent malleability and filling properties are suitable for myocardial injection and can avoid the need for open surgery. In this study, dopamine grafted hyaluronic acid (HADOPA) was synthesized and combined with sodium alginate (Alg) and Ca 2+ -loaded liposomes (Ca-FVI) to prepare a series of injectable thermosensitive sodium hyaluronate/sodium alginate hydrogels (HADOPA/Ca-FVI/Alg). At 37 °C, the HADOPA/Ca-FVI/Alg solution rapidly changed from liquid to hydrogel because of the crosslinking between sodium alginate and the Ca 2+ released from Ca-FVI at a phase transition time of 100–200 s. The HADOPA/Ca-FVI/Alg scaffolds exhibited a porous 3D network structure, controlled porosity, and connected pore properties. Increasing the proportion of HADOPA increases the elasticity and absorbance of hydrogels. Experimental assessment showed that the hydrogels have good biocompatibility and that Alg1-HADOPA is more conducive to the adhesion, proliferation, and spreading of mouse cardiac myocytes while maintaining the best cell state. These findings suggest that HADOPA/Ca-FVI/Alg hydrogels improve cell proliferation and tissue repair, and that they are a promising therapeutic option for cardiac repair after MI.
研究领域:
生物材料学
·
心血管医学
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产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
研究领域:
化学工程
·
催化化学
✓ 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）