scholarly journals Organic-inorganic hybrid materials based on N=C=O functionalised silan modified with titanium and zirconium

2005 ◽  
Vol 3 (3) ◽  
pp. 452-469 ◽  
Author(s):  
Yordanka Ivanova ◽  
Yanko Dimitriev ◽  
Tsvetelina Gerganova ◽  
Raina Bryaskova ◽  
Maria Fernandes ◽  
...  

AbstractThis work investigates the influence of the precursor trimethylsilil isocyanate on the sol-gel synthesis of hybrid materials. The obtained Si−O−C−N network is additionally modified by titanium and zirconium alcoxypropoxides in the range of 10 to 30 wt. %. The structure of the obtained hybrid materials before and after pyrolysis up to 1100°C was investigated by methods of XRD, FTIR and 29Si MAS NMR. We established that the hybrid structure was stable up to 600°C based on IR study. The structural transformation of the hybrid materials into oxycarbonitrogen system started at 800°C. The network of the hybrids modified by titanium remained stable and amorphous up to the final temperature of the pyrolysis (1100°C) compared to the gels modified by more than 10 wt.% Zr. It was confirmed by XRD analysis that the last mentioned are nanocomposite materials, built from carbooxynitrogen vitreous matrix and ZrO2-nanocrystals (tetragonal). The NMR method verified the presence of heterometallic bonds (Si−O−Ti and Si−O−Zr) and Q4, ZrQ3 or TiQ3, NSiO3 and D structural units in the gels.

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.


2012 ◽  
Vol 62 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Shang-Ru Zhai ◽  
Xu Shao ◽  
Di Zhou ◽  
Bin Zhai ◽  
Qing-Da An

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3738 ◽  
Author(s):  
A. Smalenskaite ◽  
M. M. Kaba ◽  
I. Grigoraviciute-Puroniene ◽  
L. Mikoliunaite ◽  
A. Zarkov ◽  
...  

In this study, new synthetic approaches for the preparation of thin films of Mg-Al layered double hydroxides (LDHs) have been developed. The LDHs were fabricated by reconstruction of mixed-metal oxides (MMOs) in deionized water. The MMOs were obtained by calcination of the precursor gels. Thin films of sol–gel-derived Mg-Al LDHs were deposited on silicon and stainless-steel substrates using the dip-coating technique by a single dipping process, and the deposited film was dried before the new layer was added. Each layer in the preparation of the Mg-Al LDH multilayers was separately annealed at 70 °C or 300 °C in air. Fabricated Mg-Al LDH coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was discovered that the diffraction lines of Mg3Al LDH thin films are sharper and more intensive in the sample obtained on the silicon substrate, confirming a higher crystallinity of synthesized Mg3Al LDH. However, in both cases the single-phase crystalline Mg-Al LDHs have formed. To enhance the sol–gel processing, the viscosity of the precursor gel was increased by adding polyvinyl alcohol (PVA) solution. The LDH coatings could be used to protect different substrates from corrosion, as catalyst supports, and as drug-delivery systems in medicine.


Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 109 ◽  
Author(s):  
Jadra Mosa ◽  
Jonh Fredy Vélez ◽  
Mario Aparicio

Organic/inorganic hybrid membranes that are based on GTT (GPTMS-TMES-TPTE) system while using 3-Glycidoxypropyl-trimethoxysilane (GPTMS), Trimethyletoxisilane (TMES), and Trimethylolpropane triglycidyl ether (TPTE) as precursors have been obtained while using a combination of organic polymerization and sol-gel synthesis to be used as electrolytes in Li-ion batteries. Self-supported materials and thin-films solid hybrid electrolytes that were doped with Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were prepared. The hybrid network is based on highly cross-linked structures with high ionic conductivity. The dependency of the crosslinked hybrid structure and polymerization grade on ionic conductivity is studied. Ionic conductivity depends on triepoxy precursor (TPTE) and the accessibility of Li ions in the organic network, reaching a maximum ionic conductivity of 1.3 × 10−4 and 1.4 × 10−3 S cm−1 at room temperature and 60 °C, respectively. A wide electrochemical stability window in the range of 1.5–5 V facilitates its use as solid electrolytes in next-generation of Li-ion batteries.


2013 ◽  
Vol 749 ◽  
pp. 283-288 ◽  
Author(s):  
Yury Pozhidaev ◽  
Oksana Lebedeva ◽  
Evgenya Sipkina ◽  
Alexandra Chesnokova ◽  
Nikolay Ivanov

Hybrid materials are attractive for a large range of applications from medicine and biotechnology to telecommunication systems and fuel cells. In the present research we have studied sol-gel synthesis of hybrid composites based on carbofunctional organosilicon monomers N,N-bis-(3-triethoxysilylpropyl) thiocarbamide (I) or 2-{[3-(triethoxysilyl) propyamino} pyridine (II), and copolymers of ethylene glycol vinyl glycidyl ether with vinyl chloride.The polymeric materials were characterized by scanning electron microscope (SEM) and IR-spectroscopy. Gel products possess high thermal stability (decomposition temperatures reach 250 °С) and have developed specific surface (to 20 m2g-1).The synthesized composites comprise semi-interpenetrating polymer networks, consisting of three-dimensional and linear polymers that cannot be separated due to the mechanical interlacing of theirs chains. Hybrid composites have a value of sorption capacity for Pt (IV) ions of 70 (I) and 28 (II) mgg-1. Proton conductivity of membranes based on the synthesized composites is characterized by the values 3.52 10-2(I) and 1.19 10-2(II) Scm-1measured at temperature of 25 °C.


2009 ◽  
Vol 7 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Giedre Nenartaviciene ◽  
Ramunas Skaudzius ◽  
Rimantas Raudonis ◽  
Aivaras Kareiva

AbstractThe aqueous sol-gel synthesis technique for the preparation of (Pb,Sr)Sr2(Y,Ca)Cu2O7±x (Pb-1212) and (Pb2,Cu)Sr2(Y,Ca)Cu2O8±x (Pb-3212) superconductors using two different complexing agents, namely 1,2-ethanediol and tartaric acid was studied. The phase transformations, composition and micro-structural features in the polycrystalline samples were studied by powder X-ray diffraction analysis (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis of the ceramic samples obtained by calcination of Pb-Sr-Y-Ca-Cu-O acetate-glycolate precursor gels in air, for 10 hours at 800°C and at 825°C, showed the presence of homogeneous Pb-1212 and Pb-3212 crystallites as major phases. The XRD patterns of the ceramics obtained from Pb-Sr-Y-Ca-Cu-O acetate-tartrate precursor gels, however, showed multiphasic character. The critical temperature of superconductivity (TC (onset)) observed by resistivity measurements were found to be 91 K and 75 K for Pb-1212 and Pb-3212 samples, respectively.


2002 ◽  
Vol 726 ◽  
Author(s):  
Maguy Jaber ◽  
Jocelyne Miehe-Brendle ◽  
Ronan Le Dred

AbstractHybrid materials like organo-phyllosilicates exhibit new properties which make them potential candidates for many industrials applications as rubber reinforcement, environmental barriers…. With this aim, a series of new layered inorganic-organic solids, with organic functionalities directly bonded to the inorganic sheets via the Si-C bond, were prepared by a template sol-gel synthesis under soft conditions (room temperature) using octyltriethoxysilane as the silica source, aluminum acetylacetonate as the alumina source, magnesium nitrate and sodium hydroxide. These hybrid materials belong to the 2:1 trioctahedral phyllosilicates family with inorganic compositions close to saponite. The ratio of Al (x) could be varied between 0 and 0.33. The x-ray diffraction patterns agree with a layers structure (presence of the (00l) peak series and the (060) peak). The high d001 spacing values (2.4-2.6 nm) can be related to the octyl chains present in the interlayer space. DRIFT and 13C NMR spectra indicate that the Si-C bonds are intact and siloxanes are fully hydrolyzed giving SiOAl and SiOMg bonds. 27Al and 29Si NMR were carried out in order to determine the repartition of the different elements in the layer: Al substitutes for Si in the tetrahedral layer and for Mg in the octahedral one. These results were determined by elemental analysis. The DTA-TG results show that the organic matter start to decompose in air above 250°C but its complete removal needs temperatures higher then 800°C. The aspect of the materials depends on the value of x; it varies from greasy, waxy, waxy powdery and finally powdery. The hydrophilicity of the solids depends strongly on the aluminum content.


1999 ◽  
Vol 22 (3) ◽  
pp. 201-205 ◽  
Author(s):  
J Livage

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