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981.
Antimicrobial,mechanical, optical and thermal properties of PVC/ZnO‐EDTA nanocomposite films 下载免费PDF全文
Covalent surface functionalization of synthesized ZnO nanoparticles (NP)s with ethylenediaminetetraacetic acid (EDTA) was successfully carried out. Modified ZnO‐EDTA NPs as a viable and inexpensive filler were incorporated into poly(vinyl chloride) PVC matrix after their chemical modification to investigate the agglomeration behavior. All prepared materials including modified NPs and PVC/ZnO‐EDTA nanocomposites (NC)s were analyzed by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, X‐ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. Fabricated PVC/ZnO‐EDTA NCs were reported to have high transparency and improved mechanical properties compared with PVC. Modified ZnO and the fabricated NCs were shown to exhibit excellent antibacterial activity against two bacteria species: Escherichia coli and Staphylococcus aureus. The obtained NCs could be considered as self‐extinguishing materials on the basis of the LOI values. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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983.
Optimization and characterization of electrospun chitosan/poly(vinyl alcohol) nanofibers as a phenol adsorbent via response surface methodology 下载免费PDF全文
Aliyeh Yousefi Abdolmaleki Hamid Zilouei Saied Nouri Khorasani Amir Abdolmaleki 《先进技术聚合物》2017,28(12):1872-1878
Fabrication and characterization of chitosan/poly(vinyl alcohol) electrospun nanofibers for adsorption of phenol from water were investigated. The effects of voltage (15–30 kV), solution injection flow rate (0.5–1.5 ml/hr), distance of needle and collector (10–20 cm) and chitosan/poly(vinyl alcohol) ratio (25/75, 50/50, 75/25) were studied to obtain the optimum electrospinning conditions for the maximum adsorption capacity of phenol. Central composite design (CCD) was used to investigate and optimize the processing factors for production of chitosan/poly(vinyl alcohol) nanofibers from aqueous solutions. The nanofibers were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR). Uniform beadless nanofibers with the minimum diameters of 3–11 nm were obtained at chitosan/poly(vinyl alcohol) ratio of 50/50, voltage of 22.5 kV, distance of 15 cm and injection flow rate of 1.99 ml hr?1. Fourier transform infrared spectrum of chitosan/poly(vinyl alcohol) exhibited the existence of relevant functional groups of both poly(vinyl alcohol) and chitosan in the blends. Results of CCD show that among all processing factors, rate of electrospinning will highly affect the nanofiber adsorption. The response surface quadratic order model presented correlation coefficient explaining 69.5% of the variability in the adsorption. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Julibeth M. Martinez‐De la Hoz Ivan A. Konstantinov Steven G. Arturo Gary Dombrowski 《Macromolecular theory and simulations》2016,25(5):475-481
In this work, reactions between industrially relevant monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, vinyl acetate, and isopropenyl acetate) and oxygen‐centered radicals (•OH and SO4 •—) are studied using a combination of quantum mechanics and transition state theory. These reactions may have a strong influence on polymer structure and properties. Thus, computational methodologies able to estimate reliably coefficients for these reactions are needed to improve the understanding of emulsion polymerization processes. In the case of reactions involving •OH, the computational approach is based on the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//B3LYP/6‐31+G(d, p) DFT scheme. All calculated and experimental Gibbs free energy barriers, , are within 1 kcal mol−1. In the case of reactions involving SO4•—, the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//CAM‐B3LYP/6‐31+G(d, p) DFT scheme is found to be more suitable than a similar scheme based on B3LYP. This proposed scheme works well for acrylates and methacrylates (errors within 1 kcal mol−1), but it may overestimate the rate coefficients of acetates reacting with SO4• — .
987.
We review recent progress in preconcentration strategies associated to vapor generation techniques coupled to atomic spectrometric (VGT-AS) for specific chemical species detection. This discussion focuses on the central role of different preconcentration approaches, both before and after VG process. The former was based on the classical solid phase and liquid–liquid extraction procedures which, aided by automation and miniaturization strategies, have strengthened the role of VGT-AS in several research fields including environmental, clinical, and others. We then examine some of the new vapor trapping strategies (atom-trapping, hydride trapping, cryotrapping) that entail improvements in selectivity through interference elimination, but also they allow reaching ultra-low detection limits for a large number of chemical species generated in conventional VG systems, including complete separation of several species of the same element. This review covers more than 100 bibliographic references from 2009 up to date, found in SCOPUS database and in individual searches in specific journals. We finally conclude by giving some outlook on future directions of this field. 相似文献
988.
Synthesis of Novel 1,2,4‐oxadiazoline Derivatives Containing Quinoline Moiety by 1,3‐Dipolar Cycloaddition 下载免费PDF全文
A series of novel 1,2,4‐oxadiazoline derivatives containing 2‐(1,2,4‐triazol‐1‐yl)quinoline were synthesized by the reaction of imines with benzohydroximinoyl chlorides in the presence of Et3N via 1,3‐diplolar cycloaddition reaction. The structures of the target compounds were confirmed by IR, 1H NMR, MS, elemental, and X‐ray crystallographic analysis. 相似文献
989.
水热条件下,合成了2个结构新颖的金属配位聚合物:[Co1.5(btb)2(nbta)(H2O)2]n(1),[Cd(btb)0.5(nph)(H2O)]n(2)(btb=4,4'-二(1,2,4-三氮唑-1-基)联苯,H3nbta=5-硝基-1,2,3-苯三甲酸,H2nph=3-硝基邻苯二甲酸)并对它们进行了元素分析,红外光谱及X-射线单晶衍射等表征。结构分析表明,化合物1是一个二维(3,4)-连接3,4L90拓扑结构,并进一步通过O-H…O氢键作用构筑成三维超分子结构。而配合物2是一个三维(3,4,4)-连接的sqc69网络,它的拓扑符号为(4.82)2(42.82.102)(8.104.12)。此外,还研究了这两个配合物的热重和荧光性质。 相似文献
990.
Baolei Wang Yanxia Shi Yizhou Zhan Liyuan Zhang Yan Zhang Lizhong Wang Xiao Zhang Yonghong Li Zhengming Li Baoju Li 《中国化学》2015,33(10):1124-1134
Series of novel furan/thiophene and piperazine‐containing 1,2,4‐triazole Mannich bases and bis(1,2,4‐triazole) Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, various piperazine derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points, 1H NMR, 13C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds exhibited significant in vitro and in vivo fungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl‐containing compounds showed superior activity than the methyl‐containing ones. Several compounds, such as F8 , F9 , F10 , G5 , H7 , H8 , I3 and I4 , were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity against Brassica campestris at 100 µg/mL and KARI inhibitory activity at 200 µg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 µg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agrochemicals with novel heterocyclic structures. 相似文献