期刊:
Journal of Macromolecular Science - Pure and Applied Chemistry,2023年60(9):609-617 ISSN:1060-1325
通讯作者:
Xiao, Lifen;Li, W
作者机构:
[Xiao, Lifen; Li, Liang; Zhu, Xiaoming; Huang, Geng; Li, W; Li, Wei; Lin, Dongyang] Hengyang Normal Univ, Coll Chem & Mat Sci, Key Lab Organometall New Mat, Hengyang, Peoples R China.;[Xiao, Lifen; Li, Liang; Zhu, Xiaoming; Huang, Geng; Li, W; Li, Wei; Lin, Dongyang] Hengyang Normal Univ, Coll Hunan Prov, Hunan Prov Key Lab Funct Met Organ Cpds, Hengyang, Peoples R China.
通讯机构:
[Xiao, LF; Li, W ] H;Hengyang Normal Univ, Coll Chem & Mat Sci, Key Lab Organometall New Mat, Hengyang, Peoples R China.;Hengyang Normal Univ, Coll Hunan Prov, Hunan Prov Key Lab Funct Met Organ Cpds, Hengyang, Peoples R China.
摘要:
Bottlebrushes have intensive applications in photonics, surfactants, supersoft elastomers, medical imaging, drug delivery and nanomaterials owing to their unique morphology and properties. While the traditional grafting from method required low monomer conversion to avoid gelation, and resulted shorter side chain length. Compared with the traditional grafting from method, the bottlebrushes with improved longer side chains were successfully prepared by combining grafting through and grafting from methods. In this approach, RAFT and ROMP polymerizations were used in sequence to synthesize a series of main chains: including PNB-PMA(7), PNB-PMA(13) and PNB-PMA(25). RAFT polymerization was then used to prepare bottlebrushes with different kinds of main chains under the same conditions. In the meantime, homo-polymerization of PMA was appeared inevitably, which was related to the polymerization time. Owing to the greater molecular weight of PNB-PMA(13) and PNB-PMA(25), the polymerized solutions transformed into gel in shorter time, and resulted to the lower proportion of homo-polymerization (<11%). Compared with PNB-SCS as main chain, the side chain's degree of polymerization increased from 41 to 80 when PNB-PMA(13) was used as main chain.
摘要:
In this paper, a sensitive electrochemical sensor based on MnO2 nanoparticles functionalized carboxylated multi -walled carbon nanotubes (MnO2-c-MWCNTs) was prepared for the determination of curcumin. The synthesized materials have been fully characterized by instruments, such as X-ray diffraction (XRD), scanning electron mi-croscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electro-chemical behavior of curcumin on the MnO2-c-MWCNTs modified glassy carbon electrode (MnO2-c-MWCNTs/ GCE) was investigated in detail by CV and chronocoulometry (CC). The electrochemical reaction mechanism of curcumin on the modified electrode was also discussed. In 0.1 M H2SO4 solution, the peak current showed a good linear dependence on curcumin concentration in the range of 0.01-1 mu M and 1-80 mu M, The method has high sensitivity (3.30 mu A mu M-1 cm( -1)), and the detection limit is 6.0 nM. At the same time, the MnO2-c-MWCNTs/GCE has good anti-interference ability and stability. In addition, the sensor was used for the accurate and rapid determination of curcumin in commercial food samples, which shows its good potential for practical application.
作者机构:
[Lai, Hua; Li, Yulin; Liu, Xuya; Huang, Geng; Li, Wei; Wang, Ping] Hengyang Normal Univ, Coll Chem & Mat Sci, Hengyang 421008, Peoples R China.;[Yang, Po] Sichuan Univ, Coll Polymer Sci & Engn, Chengdu 610065, Peoples R China.
通讯机构:
[Hua Lai; Po Yang] C;College of Polymer Science and Engineering, Sichuan University, Chengdu, China<&wdkj&>College of Chemistry and Material Science, Hengyang Normal University, Hengyang, China
摘要:
Mannich-type polycondensation with 4,4’-diaminodiphenylmethane (DDM), 2,2-bis(4-hydroxyphenol) propane (BPA) and paraformaldehyde (PF) in different solvents was carried out to prepare main-chain benzoxazines. When pure CHCl3 was used as the solvent, the decomposition rate of PF in CHCl3 was very slow, thus preventing gelation caused by the formation of triazine in the early reaction, producing P(B-D)1 composed of partially closed and unclosed structures. The addition of alkaline triethylamine into CHCl3 (CHCl3/triethylamine = 6:1) greatly enhanced the decomposition rate of PF but gave a large triazine gel. The introduction of triethanolamine into CHCl3 was found to promote the decomposition of PF, enhance the polymerization rate, and prevent gelation caused either by the formation of triazine or by the ring-opening of oxazine ring through a solvation effect. Polymers P(B-D) 6~P(B-D)8 obtained in CHCl3/triethanolamine had a high-oxazine content and a high number molecular weight (Mn) near 8000. Further optimization of Mannich-type polycondensation in CHCl3/triethanolamine gave preferred conditions: a CHCl3/triethanolamine ratio of 4:1, a PF of 1.2 eq and a reaction time of 24 h. Compared with P(B-D)1 and P(B-D)3 (obtained in toluene/ethanol), P(B-D)9 obtained under the optimized conditions showed a higher Mn (10,000) and a higher yield (97.0%). The optimized conditions were also applicable for other kinds of diamines and bisphenols. Mannich-type polycondensation of diamines, bisphenols and PF was conducted in CHCl3, CHCl3/triethylamine, and CHCl3/triethanolamine, respectively. The products were greatly affected by the solvents used. Owing to the combination of alkalinity and solvation effect of triethanolamine, CHCl3/triethanolamine was preferable for Mannich-type polycondensation which gave main-chain benzoxazines possessing Mn up to 10,000, oxazine content >80.0% and yield >96.0%.
期刊:
Journal of Polymer Science,2021年59(1):100-107 ISSN:2642-4150
通讯作者:
Xiao, Lifen
作者机构:
[Xiao, Lifen; Huang, Geng; Li, Jie; Li, Wei; Li, Wenyi] Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Coll Chem & Mat Sci, Hengyang 421008, Peoples R China.
通讯机构:
[Xiao, Lifen] H;Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Coll Chem & Mat Sci, Hengyang 421008, Peoples R China.
摘要:
Multiblock copolymer brushes have broad application in thermoplastic elastomers, drug delivery, porous materials, and nanolithography due to their unique structure and properties. In this research, a novel multiblock copolymer brush (PHEA-g-PEG)(x)-co- (PEG(23))(y) was synthesized by combining the efficient double strain-promoted azide-alkyne cycloaddition (DSPAAC) and copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reactions. The gel permeation chromatography (GPC), proton nuclear magnetic resonance spectrometer (H-1 NMR), Fourier transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM) were used to characterize the prepared polymers. The results demonstrated that the novel multiblock copolymer brush was successfully prepared. The mole ratio was 1/0.84 between block PHEA-g-PEG and block PEG(23), and the grafting density was 100%. The AFM image showed the morphologies of cylinder, sphere, and beads on a string owning to the random distribution of PHEA-g-PEG and PEG.
摘要:
A new Cd-MOF containing the nucleobase adenine and multicarboxylates, Cd-2(tdc)(2)(1H-ade)(2)(H2O) (H(2)tdc = 2,5-thiophene carboxylic acid, 1H-ade = adenine), was synthesized successfully under hydrothermal condition and characterized by single-crystal X-ray diffraction, infrared spectrum, thermogravimetric analysis and photoluminescence. The two crystallographically unsymmetrical Cd atoms are bridged by 2,5-tdc ligands with (kappa(1)-kappa(1))-(kappa(1))-mu(3) and (kappa(1)-kappa(1))-mu(2) modes into two dimensional extended layers, which are further pillared with the neutral ade molecules to form a 3D frameworks stabilized by extensive pi center dot center dot center dot pi interactions between imidazole-, pyrimidine- and thiophene-rings. Inspection of the structure reveals that the architecture can be simplified as a 3,4,5- connected networks with a Schlafli symbol of (6(2)center dot 8)(4(2)center dot 6(3)center dot 8)(4(2)center dot 6(5)center dot 8(3)). The photochemical property shows that the luminescent emission can be significantly quenched by aromatic azo compounds. The quenching effect coefficient (K-sv) for bis(4-imidazol-1-yl-phenyl)diazene is determined to be 4.1 x 10(4) m(-1), indicating the title compound as a potential fluorescent sensing materials.
关键词:
A. Ceramic;B. Glass;C. High temperature corrosion;D. Oxide coatings
摘要:
High-temperature degradation of the plasma sprayed LaMA coating before and after in-situ laser-glazing under CMAS attacks at 1350 degrees C for 1 h, 12 h and 48 h was comparatively investigated. Results indicate that a dense laser-glazed top layer was successfully created in-situ for a similar to 1 mm thick LaMA coating. It behaved as a sealing layer and reservoir of Al3+, Mg2+ and La3+. Melted CMAS penetration was accordingly effectively arrested accompanied by crystallizations of the CaAl2Si2O8 anorthite, MgAl2O4 spinel and Ca2La8(SiO4)(6)O-2 apatite. CMAS-induced degradation mainly occurred near the surface of the laser-glazed dense LaMA top layer. While significant penetration of the melted CMAS along the entire thickness occurred to the as-sprayed LaMA coating without laser-glazing treatments after 48 h degradation. Ca2La8(SiO4)(6)O-2 apatite phase did not crystallize for the as-sprayed LaMA due to the much reduced local La3+ concentration in melted CMAS resulted from its porous microstructure. Effects of laser-glazing on the CMAS-induced degradation of the plasma sprayed LaMA was carefully analyzed and discussed in terms of the coating's chemical composition, microstructure and surface physical chemistry characteristics base on XRD, SEM/EDS and TEM results.
作者机构:
[Fu, Wei-Wei; Li, Ya-Qian; Li, Wei; Yang, Ying-Qun; Liu, Yang; Chen, Man-Sheng] Key Laboratory of Functional Organometallic Materials of General Colleges and Universities in Hunan Province, Department of Chemistry and Materials Science, Hengyang Normal University, Hengyang 421008, People's Republic of China
通讯机构:
[Fu, W.-W.] K;Key Lab. of Funct. Organometallic Materials of General Colleges and Universities in Hunan Province, Department of Chemistry and Materials Science, Hengyang Normal University, Hengyang, China
期刊:
Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences,2015年70(4):215-219 ISSN:0932-0776
通讯作者:
Li, Heng-Feng
作者机构:
[Li, Wei; Li, Heng-Feng] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Li, Wei; Yang, Ying-Qun] Hengyang Normal Univ, Dept Chem & Mat Sci, Hunan Prov Coll, Key Lab Funct Organomet Mat, Hengyang 421008, Hunan, Peoples R China.;[Li, Chang-Hong] Hunan Inst Technol, Coll Mat & Chem Engn, Hengyang 421002, Hunan, Peoples R China.
通讯机构:
[Li, Heng-Feng] C;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.
关键词:
And electrochemical properties;Copper(II) coordination polymer;Crystal structure;Fluorescent;Magnetic;Thermal stability
摘要:
A new copper(II) coordination polymer [Cu-2(C5H4NCOO)(2)(C7H5N4)(2)](n) (1) has been synthesized with 4-pyridinecarboxylate and 3-(pyridin-2-yl)-1,2,4-triazolyl ligands. The crystal structure shows that two neighboring copper(II) ions are coordinated with two deprotonated (anionic) 3-(pyridin-2-yl)-1,2,4-triazole ligands to form a binuclear structure. Adjacent binuclear units are linked by 4-pyridinecarboxylate anions to form a three-dimensional network structure. The magnetic, fluorescent, and electrochemical properties and thermal stability of 1 were studied. The results show that 1 exhibits antiferromagnetic interaction, and upon excitation at 318 nm, it has an intense fluorescent emission at approximately 430 nm. The electron transfer of 1 is irreversible in electrode reactions. The thermogravimetric analysis shows that 1 is stable below 240 degrees C.
摘要:
Activated palm kernel shell carbon (APKSC) was used to remove U(VI) from aqueous solutions in a batch system. The adsorption kinetics, isotherms, and effects of various parameters, such as temperature, contact time, solution pH, adsorbent dosage, and initial U(VI) concentration on the U(VI) adsorption process were studied. Equilibrium was reached after 120 min in the range of studied U(VI) concentrations and temperatures. U(VI) uptake was insignificantly affected by temperature, but was highly pH dependent, and the optimum pH for removal was 5.5. U(VI) removal efficiency increased with the increasing adsorbent dosage. U(VI) sorption capacity increased with increasing initial U(VI) concentration; any further increases in initial U(VI) concentration above a certain point caused insignificant changes in U(VI) sorption capacity. Isotherm data could be described by the Langmuir isotherm model with a maximum U(VI) adsorption capacity of 51.81 mg/g. Kinetic data were fitted to pseudo-first-order and pseudo-second-order equations, which suggested that the U(VI) adsorption onto APKSC was better reproduced by the pseudo-second-order model rather than pseudo-first-order model. Our results indicated that APKSC might be used as a cheap adsorbent in the treatment of uranium-containing wastewater.
关键词:
Direct reduced iron (DRI);Uranium;Kinetics;pH;Mechanism
摘要:
Direct reduced iron (DRI), also called sponge iron, was used for the removal of U(VI) from aqueous solution. Batch experiments were conducted to evaluate the effect of various factors including contact time, solution pH, DRI dosage and initial uranium concentration on this removal process. The result suggested that U(VI) can be rapidly removed by DRI and this removal process followed an apparent first-order reaction kinetics. The optimum pH for uranium removal was between 2.0 and 4.0. Whether U(VI) can be fully removed was influenced by the molar ratio of DRI to U(VI) in solution. The aqueous U(VI) can be removed completely when this ratio was more than ca. 1,000. The U(VI) removal capacities of DRI decreased with increasing DRI dosages at a constant concentration of U(VI), but increased almost linearly with increasing initial U(VI) concentrations at a fixed dosage of DRI. The maximum U(VI) removal capacity was 5.71 mg/g DRI. Finally, the possible mechanism of U(VI) removal by DRI was also discussed. The XPS and XRD analysis showed that U(VI) was deposited as UO3 onto DRI surface, indicating that U(VI) can be removed without reduction.
摘要:
Two new 3d-4f heterometallic coordination polymers [Mn(0.5)Ln(INAIP)(2)(H2O)(2)]center dot 2H(2)O [ Ln = Eu (1), Gd (2)] have been prepared by hydrothermal reactions of the corresponding lanthanide salt with 5-(isonicotinamido) isophthalic acid (H(2)INAIP) in the presence of MnCO3 and NaOH. Both complexes have been characterized by single crystal X-ray diffraction analyses, elemental analyses, infrared absorption spectra, and thermogravimetric analyses. The results of structural analyses show that 1 and 2 are isostructural and feature non-interpenetrated 3D coordination framework containing 2D (4,4) lanthanide-carboxylate layers. They have the same 3D structure with trinodal (3,3,4)-connected new topology net with Point (Schlafli) symbol (8(3))(4)(8(4).10(2))(8(6))(2). In addition, photoluminescence and magnetic properties were also investigated. (C) 2011 Elsevier B. V. All rights reserved.
期刊:
Zeitschrift fur Kristallographie - New Crystal Structures,2011年226(1):15-16 ISSN:1433-7266
通讯作者:
Li, Wei
作者机构:
[Li, Wei; Yang, Ying-Qun; Tan, Xiong-Wen] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.;[Li, Changhong] Hunan Inst Technol, Dept Chem Engn, Hengyang 421002, Peoples R China.
通讯机构:
[Li, Wei] H;Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.
摘要:
C28H28.42CuN4O8.43, orthorhombic, Pccn (no. 56), a = 25.361(4) angstrom, b = 6.604(1) angstrom, c = 16.771(3) angstrom, V = 2808.8 angstrom(3), Z = 4, R-gt(F) = 0.036, wR(ref)(F-2) = 0.112, T = 296 K.
摘要:
A new 3D fourfold interpenetrated metal-organic framework, [Co(L)(2)(SO4)]center dot H2O (1), has been synthesized by the solvothermal reaction of L with CoSO4 center dot 6H(2)O (L = 1,4-bis(imidazolyl)benzene). Compound 1 crystallizes in the monoclinic space group P2(1)/n, with the cell parameters: a = 9.943(2), b = 21.7104(15), c = 13.2658(18) angstrom, ss = 97.638(3)degrees, V = 2838.2(8) angstrom(3), R-1 = 0.0566 and wR(2) = 0.1035. It represents a novel dia net, in which the cobalt atoms are alternately bridged by the imidazolyl N atoms of the ligands L into a three-dimensional network. Compound 1 displays antiferromagnetic interactions. From 2 to 300 K, chi m(-1) it obeys the Curie-Weiss law with C = 2.68 emu K mol(-1) and Theta = -2.59 K.