共查询到20条相似文献,搜索用时 46 毫秒
1.
Hongfu Zhou Chen Zhang Hangquan Li Zhongjie Du 《Journal of polymer science. Part A, Polymer chemistry》2010,48(21):4697-4703
Fe3O4 nanoparticles were indirectly implanted onto functionalized multi‐walled carbon nanotubes (MWCNTs) leading to a nanocomposite with stronger magnetic performance. Poly(acrylic acid) (PAA) oligomer was first reacted with hydroxyl‐functionalized MWCNTs (MWCNTs‐OH) forming PAA‐grafted MWCNTs (PAA‐g‐MWCNTs). Subsequently, Fe3O4 nanoparticles were attached onto the surface of PAA‐g‐MWCNTs through an amidation reaction between the amino groups on the surface of Fe3O4 nanoparticles and the carboxyl groups of PAA. Fourier transform infrared spectra confirmed that the Fe3O4 nanoparticles and PAA‐g‐MWCNTs were indeed chemically linked. The morphology of the nanocomposites was characterized using transmission electron microscope (TEM). The surface and bulk structure of the nanocomposites were examined using X‐ray diffraction, X‐ray photoelectron spectrometer (XPS), and thermogravimetric analysis (TGA). The magnetic performance was characterized by vibrating sample magnetometer (VSM) and the magnetic saturation value of the magnetic nanocomposites was 47 emu g?1. The resulting products could be separated from deionized water under an external magnetic field within about 15 s. Finally, the magnetorheological (MR) performances of the synthesized magnetic nanocomposites and pure Fe3O4 nanoparticles were examined using a rotational rheometer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
2.
A novel technique of fabricating magnetic thermoplastic nanofibers by the control of the phase separation of immiscible polymer blends during melt extrusion was presented. The magnetic poly(vinyl alcohol‐co‐ethylene) (PVA‐co‐PE)/Fe3O4 composite nanofibers were prepared via the melt extrusion of cellulose acetate butyrate matrix and PVA‐co‐PE preloaded with different amounts of Fe3O4 nanoparticles. The morphologies of magnetic composite nanofibers were characterized by scanning electron microscopy. The uniform dispersion of Fe3O4 nanoparticles in nanofiber matrixes and crystal structures were confirmed using transmission electron microscopy and wide angle X‐ray diffraction. Thermogravimetric analysis was employed to quantify the exact loading amount of Fe3O4 nanoparticles in the composite nanofibers. The magnetic measurements showed that composite nanofibers displayed superparamagnetic behavior at room temperature. With increasing content of Fe3O4 nanoparticles, the saturation magnetization of the magnetic composite nanofiber significantly improved. The prepared magnetic composite nanofibers might have found potential applications in the sensors and bio‐molecular separation fields. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
《应用有机金属化学》2017,31(11)
An efficient procedure based on arginine‐modified Fe3O4@carbon magnetic nanoparticles (FCA MNPs) with highly dispersed copper nanoparticles (Cu NPs) and 92.8 ppm of Pd is reported for room temperature Suzuki reaction. For enhancing the activity of this Cu‐based heterogeneous catalyst, special arginine amino acid as a ligand with high content of heteroatoms was immobilized onto the Fe3O4@carbon MNPs to increase the electron density. Cu(II) ions were then loaded on the surface of the FCA MNPs and reduced to achieve uniformly dispersed Cu NPs. An aqueous mixture of metal hydroxides such as KOH, Ba(OH)2, Ca(OH)2, Mg(OH)2 as a green, non‐toxic and basic medium was used for the Suzuki reaction at room temperature. This catalyst could also be recovered and reused with no loss of activity over six successful runs. 相似文献
4.
Mingliang Ma Yuying Yang Dili Liao Ping Lyu Jinwei Zhang Jianli Liang Lizhi Zhang 《应用有机金属化学》2019,33(2)
A strategy has been developed for the synthesis, characterization and catalysis of magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd core‐shell structure supported catalyst. The P(GMA‐EGDMA) polymer layer was coated on the surface of hollow magnetic Fe3O4 microspheres through the effect of KH570. The core‐shell magnetic Fe3O4/P(GMA‐EGDMA) modified by ‐NH2 could be grafted with HPG. Then, the hyperbranched glycidyl (HPG) with terminal ‐OH were modified by ‐COOH and adsorbed Pd nanoparticles. The hyperbranched polymer layer not only protected the Fe3O4 magnetic core from acid–base substrate corrosion, but also provided a number of functional groups as binding sites for Pd nanoparticles. The prepared catalyst was characterized by UV–vis, TEM, SEM, FTIR, TGA, ICP‐OES, BET, XRD, DLS and VSM. The catalytic tests showed that the magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd catalyst had excellent catalytic performance and retained 86% catalytic efficiency after 8 consecutive cycles. 相似文献
5.
The Synthesis of Magnetic Lysozyme‐Imprinted Polymers by Means of Distillation–Precipitation Polymerization for Selective Protein Enrichment
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jiali Cao Xihao Zhang Prof. Xiwen He Prof. Langxing Chen Prof. Yukui Zhang 《化学:亚洲杂志》2014,9(2):526-533
A protein imprinting approach for the synthesis of core–shell structure nanoparticles with a magnetic core and molecularly imprinted polymer (MIP) shell was developed using a simple distillation–precipitation polymerization method. In this work, Fe3O4 magnetic nanoparticles were first synthesized through a solvothermal method and then were conveniently surface‐modified with 3‐(methacryloyloxy)propyltrimethoxylsilane as anchor molecules to donate vinyl groups. Next a high‐density MIP shell was coated onto the surface of the magnetic nanoparticles by the copolymerization of functional monomer acrylamide (AAm), cross‐linking agent N,N′‐methylenebisacrylamide (MBA), the initiator azodiisobutyronitrile (AIBN), and protein in acetonitrile heated at reflux. The morphology, adsorption, and recognition properties of the magnetic molecularly imprinted nanoparticles were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and rebinding experiments. The resulting MIP showed a high adsorption capacity (104.8 mg g?1) and specific recognition (imprinting factor=7.6) to lysozyme (Lyz). The as‐prepared Fe3O4@Lyz‐MIP nanoparticles with a mean diameter of 320 nm were coated with an MIP shell that was 20 nm thick, which enabled Fe3O4@Lyz‐MIP to easily reach adsorption equilibrium. The high magnetization saturation (40.35 emu g?1) endows the materials with the convenience of magnetic separation under an external magnetic field and allows them to be subsequently reused. Furthermore, Fe3O4@Lyz‐MIP could selectively extract a target protein from real egg‐white samples under an external magnetic field. 相似文献
6.
Wenjing Zhang Xinhao Shi Dr. Jing Huang Yixuan Zhang Prof. Zirong Wu Prof. Yuezhong Xian 《Chemphyschem》2012,13(14):3388-3396
Bacitracin‐conjugated superparamagnetic iron oxide (Fe3O4) nanoparticles were prepared by click chemistry and their antibacterial activity was investigated. After functionalization with hydrophilic and biocompatible poly(acrylic acid), water‐soluble Fe3O4 nanoparticles were obtained. Propargylated Fe3O4 nanoparticles were then synthesized by carbodiimide reaction of propargylamine with the carboxyl groups on the surface of the iron oxide nanoparticles. By further reaction with N3‐bacitracin in a CuI‐catalyzed azide–alkyne cycloaddition, the magnetic Fe3O4 nanoparticles were modified with the peptide bacitracin. The functionalized magnetic nanoparticles were characterized by powder X‐ray diffraction, X‐ray photoelectron spectroscopy, TEM, zeta‐potential analysis, FTIR spectroscopy and vibrating‐sample magnetometry. Cell cytotoxicity tests indicate that bacitracin‐conjugated Fe3O4 nanoparticles show very low cytotoxicity to human fibroblast cells, even at relatively high concentrations. In view of the antibacterial activity of bacitracin, the biofunctionalized Fe3O4 nanoparticles exhibit an antibacterial effect against both Gram‐positive and Gram‐negative organisms, which is even higher than that of bacitracin itself. The enhanced antibacterial activity of the magnetic nanocomposites allows the dosage and the side effects of the antibiotic to be reduced. Due to the antibacterial effect and magnetism, the bacitracin‐functionalized magnetic nanoparticles have potential application in magnetic‐targeting biomedical applications. 相似文献
7.
Xuan Kong Fei Li Yijun Li Xiwen He Langxing Chen Yukui Zhang 《Journal of separation science》2020,43(4):808-817
We present a facile strategy to prepare the molecularly imprinted polymers layer on the surface of Fe3O4 nanoparticles with core‐shell structure via sol–gel condensation for recognition and enrichment of triclosan. The Fe3O4 nanoparticles were first synthesized by a solvothermal method. Then, template triclosan was self‐assembled with the functional monomer 3‐aminopropyltriethoxysilane on the silica‐coated Fe3O4 nanoparticles in the presence of ethanol and water. Finally, the molecularly imprinted polymers were formed on the surface of silica‐coated Fe3O4 nanoparticles to obtain the product. The morphology, magnetic susceptibility, adsorption, and recognition property of magnetic molecularly imprinted polymers were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffractometry, vibrating sample magnetometry, and re‐binding experiments. The magnetic molecularly imprinted polymers showed binding sites with good accessibility, fast adsorption rate, and high adsorption capacity (218.34 μg/g) to triclosan. The selectivity of magnetic molecularly imprinted polymers was evaluated by the rebinding capability of triclosan and two other structural analogues (phenol and p‐chlorophenol) in a mixed solution and good selectivity with an imprinting factor of 2.46 was obtained. The application of triclosan removal in environmental samples was demonstrated. 相似文献
8.
A novel chiral magnetic nanocatalyst was prepared by the surface modification of Fe3O4 magnetic nanoparticles (MNPs) with a chloropropylsilane and further by arginine to form Fe3O4@propylsilan‐arginine (Fe3O4@PS‐Arg). After the structural confirmation of Fe3O4@PS‐Arg synthesized MNPs by Fourier transform‐infrared, X‐ray diffraction, field emission‐scanning electron microscopy, transmission electron microscopy, vibrating‐sample magnetometry and thermogravimetric analyses, their catalytic activity was evaluated for one‐pot enantioselective synthesis of 3‐amino‐1‐aryl‐1H‐benzo[f]chromene‐2‐carbonitrile derivatives. The results showed that in the presence of 0.07 g Fe3O4@PS‐Arg nanocatalyst and ethanol as solvent, the best reaction yield (96%) was obtained in the least time (5 min). Easy operation, reusability and stability, short reaction time, high reaction yields and good enantioselectivity are the major advantages of the newly synthesized nanocatalyst. Also, this study provides a novel strategy for further research and investigation on the synthesis of new reusable enantioselective catalysts and chiral compounds. 相似文献
9.
MgBr2 supported on Fe3O4@SiO2 ~ urea nanoparticle: An efficient catalyst for ortho‐formylation of phenols and oxidation of benzylic alcohols
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Urea was successfully immobilized on the surface of chloropropyl‐modified Fe3O4@SiO2 core–shell magnetic nanoparticles, then supported by MgBr2 and acts as a unique catalyst for oxidation of benzylic alcohols to aldehydes and ketones, and ortho‐formylation of phenols to salicylaldehydes. The prepared catalyst was characterized by FT‐IR, transmission electron microscopy, scanning electron microscopy, X‐ray powder diffraction, dispersive X‐ray spectroscopy, CHN and TGA. It was found that Fe3O4@SiO2 ~ urea/MgBr2 showed higher catalytic activity than homogenous MgBr2, and could be reused several times without significant loss of activity. 相似文献
10.
In this study, the synthesis of sulfonic acid supported on ferrite–silica superparamagnetic nanoparticles (Fe3O4@SiO2@SO3H) as a nanocatalyst with large density of acidic groups is suggested. This nanocatalyst was prepared in three steps: preparation of colloidal iron oxide magnetic nanoparticles (Fe3O4 MNPs), coating of silica on Fe3O4 MNPs (Fe3O4@SiO2) and incorporation of sulfonic acid as a functional group on the surface of Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2@SO3H). The properties of the prepared magnetic nanoparticles were characterized using transmission electron microscopy, infrared spectroscopy, vibrating sample magnetometry, X‐ray diffraction and thermogravimetric analysis. Finally, the applicability of the synthesized magnetic nanoparticles was tested as a heterogeneous solid acid nanocatalyst for one‐pot synthesis of diindolyloxindole derivatives in aqueous medium. Oxindole derivatives were produced by the coupling of indole and isatin compounds with good to high yields (60–98%). Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
11.
The heterostructured Ag nanoparticles decorated Fe3O4 Glutathione (Fe3O4‐Glu‐Ag) nanoparticles (NPs) were synthesized by sonicating glutathione (Glu) with magnetite and further surface immobilization of silver NPs on it. The ensuing magnetic nano catalyst is well characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA). The prepared Fe3O4‐Glu‐Ag nanoparticles have proved to be an efficient and recyclable nanocatalyst with low catalyst loading for the reduction of nitroarenes and heteronitroarenes to respective amines in the presence of NaBH4 using water as a green solvent which could be easily separated at the end of a reaction using an external magnet and can be recycled up to 5 runs without any significant loss in catalytic activity. Gram scale study for the reduction of 4‐NP has also being carried out successfully and it has been observed that this method can serve as an efficient protocol for reduction of nitroarenes on industrial level. 相似文献
12.
Synthesis of pH‐responsive magnetic yolk–shell nanoparticles: A comparison between conventional etching and new deswelling approaches
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Iron oxide (Fe3O4) magnetic nanoparticles as movable cores were used to synthesize yolk–shell nanoparticles with pH‐responsive shell composed of ethylene glycol dimethacrylate (EGDMA)‐crosslinked poly(acrylic acid) (PAA) via two different routes. In the first more common route, Fe3O4 nanoparticles were coated with silica layer via the Stöber process to yield Fe3O4@SiO2 core–shell nanoparticles, subsequently used as seeds in the distillation precipitation copolymerization of AA and EGDMA to yield Fe3O4@SiO2@P(AA‐EGDMA). The silica layer was selectively removed through alkali etching to yield Fe3O4@air@P(AA‐EGDMA). In the second route, Fe3O4 nanoparticles without any stabilization were used as seeds in the distillation precipitation copolymerization of AA and EGDMA to yield Fe3O4@P(AA‐EGDMA) core–shell nanoparticles. The nanoparticles were subsequently dispersed in acidic medium of pH = 2. Yolk–shell Fe3O4@air@P(AA‐EGDMA) nanoparticles were formed through deswelling of crosslinked PAA because of protonation of carboxyl groups at low pH values. Various techniques were utilized to investigate the characteristics of the synthesized core–shell nanoparticles. Formation of yolk–shell nanostructure was observed for both synthesis routes, namely etching of silica layer and deswelling approaches, from vibrating sample magnetometry and transmission electron microscopy results. Both types of nanoparticles showed pH‐responsive behaviour, i.e. decrease in absorption with increase in pH, as examined using UV–visible spectroscopy. 相似文献
13.
Targeted drug delivery is a promising approach to overcome the limitations of classical chemotherapy. In this respect, Imatinib‐loaded chitosan‐modified magnetic nanoparticles were prepared as a pH sensitive system for targeted delivery of drug to tumor sites by applying a magnetic field. The proposed magnetic nanoparticles were prepared through modification of magnetic Fe3O4 nanoparticles with chitosan and Imatinib. The structural, morphological and physicochemical properties of the synthesized nanoparticles were determined by different analytical techniques including energy‐dispersive X‐ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), Fourier‐transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HR‐TEM), vibrating sample magnetometry (VSM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). UV/visible spectrophotometry was used to measure the Imatinib contents. Thermal stability of the prepared particles was investigated and their efficiency of drug loading and release profile were evaluated. The results demonstrated that Fe3O4@CS acts as a pH responsive nanocarrier in releasing the loaded Imatinib molecules. Furthermore, the Fe3O4@CS/Imatinib nanoparticles displayed cytotoxic effect against MCF‐7 breast cancer cells. Results of this study can provide new insights in the development of pH responsive targeted drug delivery systems to overcome the side effects of conventional chemotherapy. 相似文献
14.
Dispersive liquid–liquid microextraction based on amine‐functionalized Fe3O4 nanoparticles for the determination of phenolic acids in vegetable oils by high‐performance liquid chromatography with UV detection
下载免费PDF全文
![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zhihong Shi Lingna Qiu Dan Zhang Mengyuan Sun Hongyi Zhang 《Journal of separation science》2015,38(16):2865-2872
A novel dispersive liquid–liquid microextraction method based on amine‐functionalized Fe3O4 magnetic nanoparticles was developed for the determination of six phenolic acids in vegetable oils by high‐performance liquid chromatography. Amine‐functionalized Fe3O4 was synthesized by a one‐pot solvothermal reaction between Fe3O4 and 1,6‐hexanediamine and characterized by transmission electron microscopy and Fourier transform infrared spectrophotometry. A trace amount of phosphate buffer solution (extractant) was adsorbed on bare Fe3O4‐NH2 nanoparticles by hydrophilic interaction to form the “magnetic extractant”. Rapid extraction could be achieved while the “magnetic extractant” on amine‐functionalized Fe3O4 nanoparticles was dispersed in the sample solution by vortexing. After extraction, the “magnetic extractant” was collected by application of an external magnet. Some important parameters, such as pH and volume of extraction and desorption solvents, the extraction and desorption time needed were carefully investigated and optimized to achieve the best extraction efficiency. Under the optimal conditions, satisfactory extraction recoveries were obtained for the six phenolic acids in the range of 84.2–106.3%. Relative standard deviations for intra‐ and inter‐day precisions were less than 6.3 and 10.0%, respectively. Finally, the established method was successfully applied for the determination of six phenolic acids in eight kinds of vegetable oils. 相似文献
15.
《应用有机金属化学》2017,31(10)
Green tea extract having many phenolic hydroxyl and carbonyl functional groups in its molecular framework can be used in the modification of Fe3O4 nanoparticles. Moreover, the feasibility of complexation of polyphenols with silver ions in aqueous solution can improve the surface properties and capacity of the Fe3O4@green tea extract nanoparticles (Fe3O4@GTE NPs) for sorption and reduction of silver ions. Therefore, the novel Fe3O4@GTE NPs nano‐sorbent has potential ability as both reducing and stabilizing agent for immobilization of silver nanoparticles to make a novel magnetic silver nanocatalyst (Fe3O4@GTE/Ag NPs). Inductively coupled plasma analysis, transmission and scanning electron microscopies, energy‐dispersive X‐ray and Fourier transform infrared spectroscopies, and vibrating sample magnetometry were used to characterize the catalyst. Fe3O4@GTE/Ag NPs shows high catalytic activity as a recyclable nanocatalyst for the reduction of 4‐nitrophenol at room temperature. 相似文献
16.
《Electroanalysis》2017,29(12):2896-2905
In this study, immobilized hollow nanospheres of Fe3O4 with Palladium, Platinum and Gold nanoparticles (Fe3O4HNS‐PdPtAuNPs) was synthesized by hydrothermal and chemical reduction methods and characterized by various techniques such as field emission scanning electron microscopy, energy dispersive analysis of X‐rays and elemental mapping images. The electrocatalytic activity of the modified glassy carbon electrode (GCE) with Fe3O4HNS‐PdPtAuNPs (GCE/Fe3O4HNS‐PdPtAuNPs) toward methanol electrooxidation was investigated by cyclic voltammetry and chronoamperometry in 1 M NaOH solution. According to the results, Fe3O4HNS‐PdPtAuNPs catalyst demonstrated the highest efficiency for methanol electrooxidation in comparison with Fe3O4HNS‐PdNPs, Fe3O4HNS‐PtNPs, Fe3O4HNS‐PdAuNPs, Fe3O4HNS‐PtAuNPs and Fe3O4HNS‐PdPtNPs. The value of electron transfer coefficient (α ) and the ratio of current densities (If /Ib ) for methanol oxidation on the Fe3O4HNS‐PdPtAuNPs/GC catalyst were calculated 0.61 and 5.13, respectively. The reaction order was discovered to be 0.98 for CH3OH. A direct methanol fuel cell was developed with the suggested catalyst under several conditions. 相似文献
17.
《Electroanalysis》2017,29(3):765-772
Stable magnetic nanocomposite of gold nanoparticles (Au‐NPs) decorating Fe3O4 core was successfully synthesized by the linker of Boc‐L‐cysteine. Transmission electron microscope (TEM), energy dispersive X‐ray spectroscopy (EDX) and cyclic voltammograms (CV) were performed to characterize the as‐prepared Fe3O4@Au‐Nps. The results indicated that Au‐Nps dispersed homogeneously around Fe3O4 with the ratio of Au to Fe3O4 nanoparticles as 5–10/1 and the apparent electrochemical area as 0.121 cm2. After self‐assembly of hemoglobin (Hb) on Fe3O4@Au‐Nps by electrostatic interaction, a hydrogen peroxide biosensor was developed. The Fe3O4@Au‐Nps/Hb modified GCE exhibited fast direct electron transfer between heme center and electrode surface with the heterogeneous electron transfer rate constant (Ks ) of 3.35 s−1. Importantly, it showed excellent electrocatalytic activity towards hydrogen peroxide reduction with low detection limit of 0.133 μM (S /D =3) and high sensitivity of 0.163 μA μM−1, respectively. At the concentration evaluated, the interfering species of glucose, dopamine, uric acid and ascorbic acid did not affect the determination of hydrogen peroxide. These results demonstrated that the introduction of Au‐Nps on Fe3O4 not only stabilized the immobilized enzyme but also provided large surface area, fast electron transfer and excellent biocompatibility. This facile nanoassembly protocol can be extended to immobilize various enzymes, proteins and biomolecules to develop robust biosensors. 相似文献
18.
《应用有机金属化学》2017,31(10)
A facile, green and efficient method for the immobilization of MoO2–Salen onto graphene hybridized with glucose‐coated magnetic Fe3O4 nanoparticles is proposed to fabricate a magnetic organic–inorganic hybrid heterogeneous RGO/Fe3O4@C‐Salen‐MoO2 catalyst for the epoxidation of cyclooctene and geraniol using tert ‐butyl hydroperoxide or H2O2 as oxidant. Carbon‐coated Fe3O4 can improve the stability and add functional ─OH groups on the surface of Fe3O4. The fabricated composite exhibited good performance due to good dispersion of MoO2–Salen active sites. The catalyst can be easily separated from the reaction system using a permanent magnet and used three times without significantly losing its catalytic activity and selectivity. 相似文献
19.
Zhong‐Peng Xiao Kun‐Min Yang Hui Liang Jiang Lu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(3):542-550
A reversible addition‐fragmentation chain transfer (RAFT) agent was directly anchored onto Fe3O4 nanoparticles in a simple procedure using a ligand exchange reaction of S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐acetic acid)trithiocarbonate with oleic acid initially present on the surface of pristine Fe3O4 nanoparticles. The RAFT agent‐functionalized Fe3O4 nanoparticles were then used for the surface‐initiated RAFT copolymerization of N‐isopropylacrylamide and acrolein to fabricate structurally well‐defined hybrid nanoparticles with reactive and thermoresponsive poly(N‐isopropylacrylamide‐co‐acrolein) shell and magnetic Fe3O4 core. Evidence of a well‐controlled surface‐initiated RAFT copolymerization was gained from a linear increase of number‐average molecular weight with overall monomer conversions and relatively narrow molecular weight distributions of the copolymers grown from the nanoparticles. The resulting novel magnetic, reactive, and thermoresponsive core‐shell nanoparticles exhibited temperature‐trigged magnetic separation behavior and high ability to immobilize model protein BSA. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 542–550, 2010 相似文献
20.
Magnetically recoverable and environmentally friendly Cu‐based heterogeneous catalyst has been synthesized for the one‐pot conversion of aldehydes to their corresponding primary amides. The Fe3O4@SiO2 nanocomposites were prepared by synthesis of Fe3O4 magnetic nanoparticles (MNPs) which was then coated with a silica shell via Stöber method. Bi‐functional cysteine amino acid was covalently bonded onto the siliceous shell of nanocatalyst. The CuII ions were then loaded onto the modified surface of nanocatalyst. Finally, uniformly dispersed copper nanoparticles were achieved by reduction of CuII ions with NaBH4. Amidation reaction of aryl halides with electron‐withdrawing or electron‐donating groups and hydroxylamine hydrochloride catalyzed with Fe3O4@SiO2@Cysteine‐copper (FSC‐Cu) MNPs in aqueous condition gave an excellent yield of products. The FSC‐Cu MNPs could be easily isolated from the reaction mixture with an external magnet and reused at least 8 times without significant loss in activity. 相似文献