Preparation of (Bi,Pb)2Sr2Ca2Cu3Ox precursor powders by a modified polyethylene glycol based sol–gel process

2002 ◽  
Vol 372-376 ◽  
pp. 905-908 ◽  
Author(s):  
J.-C Grivel ◽  
N.H Andersen
Keyword(s):  
Polyethylene Glycol ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Precursor Powders

Preparation of ZrC/SiC porous self-supporting monoliths via sol-gel process using polyethylene glycol as phase separation inducer

2018 ◽  
Vol 38 (14) ◽  
pp. 4806-4813 ◽  
Author(s):  
Fei Li ◽  
Xin-Gang Wang ◽  
Xiao Huang ◽  
Ji-Xuan Liu ◽  
Weichao Bao ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polyethylene Glycol ◽  
Sol Gel ◽  
Sol Gel Process

Synthesis of V2O5 Powders by EDTA Assistance Ultrasound Sol-Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 207-210
Author(s):  
Quan Wen ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Activation Energy ◽  
Raw Materials ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calcination Temperatures ◽  
Sol Gel Process ◽  
Ft Ir ◽  
Precursor Powders ◽  
Influence Of Ph

V2O5 powders were successfully synthesized by the EDTA assistanced ultrasound sol-gel process using NH4VO3 and EDTA, NH3•H2O as raw materials. The synthesized activation energy and the influence of pH values and the calcination temperatures on the phases and microstructures of powders were particularly investigated. The precursor powders and the V2O5 powders were characterized by X-ray diffraction (XRD), fourier transform inelectron microscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry-thermal gravimetric (DSC-TG). Results show that the obtained products exhibit good crystallization under the conditions of pH=4, calcination temperature 400~500 °C and calcination time 0.5 h during the synthesizing process. The as-prepared V2O5 powders show preferred growth orientation along (001) plane at the pH=4. By DSC analysis, the ultrasonic cavitation result in the decrease in synthesized activation energy obviously than that was prepared without ultrasonic irradiation.

Synthesis and Characterization of ZnO-SiO2/Epoxy Nanocomposite Coating by Sol-Gel Process

2012 ◽  
Vol 16 ◽  
pp. 1-7
Author(s):  
Nazanin Farhadyar ◽  
Mirabdullah Seyed Sadjadi
Keyword(s):  
Polyethylene Glycol ◽  
Sol Gel ◽  
Nanocomposite Coating ◽  
Contact Angles ◽  
Hybrid Coatings ◽  
Coating Film ◽  
Water Contact ◽  
Unit Form ◽  
Hybrid Solution ◽  
Sol Gel Process

In this paper, we report preparation of hydrophilic hybrid nanocomposite coatings on glass substrates using Zinc acetate solutions based on 3-glycidoxypropyltrimethoxysilane (GPTMS), epoxy resin, aromatic amine (HY850), polyethylene glycol (PEG) and surfactant (polyoxyethylene(4)laurylether) by the sol-gel process. Furthermore, the effects of PEG addition to the precursor solutions on the hydrophilic property and microstructure of the resultant coating film were studied. The hydrophilic behavior study of the synthesized hybrid was performed by adding different amounts of polyethylene glycol precursor to the hybrid solution. Experimental results show that, among different amounts of PEGs, the best results are obtained by addition of PEGs (400) to the hybrid solution which can decrease the water contact angles down to 16 and using surfactant down to 0, and increase the free surface energy. Coated glass exhibits a higher strength than uncoated glass. Attenuated total reflectance infrared spectroscopic (ATR-IR) technique was used to characterize the structure of the hybrid films. The chemical structure of obtained network affects morphology of the coating. The morphology of the hybrid coatings was examined by transmission electron microscopy (TEM). The hybrid systems have a unit form structure and the inorganic phases were in the nanosize scale,

Synthesis, Structure and Spectral Properties of Eu:YGO Phosphor Powders

2016 ◽  
Vol 852 ◽  
pp. 585-590
Author(s):  
Lin Sang ◽  
Ning Pan ◽  
Jing Su ◽  
Xiao Mei Tan ◽  
Hang Li ◽  
...  
Keyword(s):  
Spectral Properties ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectroscopy ◽  
Fluorescence Properties ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Ft Ir ◽  
Polycrystalline Phase ◽  
Precursor Powders

3at. % Eu3+ doped (Y, Gd)2O3 precursor powders with various compositions were synthesized via a sol-gel process, and the precursors were sintered at different temperatures. XRD, FT-IR, Raman and photoluminescence spectroscopy were used to study the phase, microstructure and luminescent properties of the precursors and the sintered powders. The results show that pure (Y, Gd)2O3 polycrystalline phase can be obtained from sintering the precursors at 700°C. The influences of the host compositions on the microstructures and fluorescence properties were analyzed, and the optimized composition was obtained for 3at. % Eu3+ doped (Y, Gd)2O3 powders.

scholarly journals Immobilization of Lipase CALB in Organically Modified Silica

2020 ◽  
Vol 11 (1) ◽  
pp. 7814-7825 ◽  
Keyword(s):  
Polyethylene Glycol ◽  
Sol Gel ◽  
Reaction Medium ◽  
Sol Gel Process ◽  
Yield Values ◽  
Activity Of Enzymes ◽  
Esterification Activity ◽  
Candida Antarctica B ◽  
The Mathematical Model ◽  
Commercial Lipase

In order to improve the activity of enzymes immobilized in silica, additives such as polyethylene glycol (PEG) can be introduced in the sol-gel process. This addition aims to protect the enzymes from denaturing effects by forming protection between the protein and the reaction medium. Thus, the aim of the work was to evaluate the effect of the use of the PEG additive in the process of immobilization of the commercial lipase of Candida antarctica B (CALB) in xerogel and aerogel obtained by the sol-gel technique. The mathematical model for the process was validated, and the optimum points determined were 0.09 g/ml of enzyme and 0.15 g/ml of polyethylene glycol additive for the xerogel and 0.12 g/ml of enzyme and 0.20 g/mL of polyethylene glycol additive for the aerogel. The maximum esterification activity and yield values were 544 U/g, 585%, and 266 U/g, 140% for xerogel and aerogel, respectively. Polyethylene glycol showed better performance in the esterification activity and stability as an additive when used in the xerogel, that is, when the process of obtaining the support uses the removal of the solvent only by evaporation. Regarding aerogel, a reduction in enzyme activity was observed, which may be due to the interaction of PEG with CO2 in the drying process.

Preparation and Properties of Porous Apatite-Wollastonite Bioactive Glass-Ceramic

2007 ◽  
Vol 330-332 ◽  
pp. 169-172 ◽  
Author(s):  
Ming Xue ◽  
Jun Ou ◽  
Da Li Zhou ◽  
Dange Feng ◽  
Wei Zhong Yang ◽  
...  
Keyword(s):  
Bioactive Glass ◽  
Stromal Cells ◽  
Glass Ceramic ◽  
Sol Gel ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Polymer Foam ◽  
Physical Chemical ◽  
Sol Gel Process ◽  
Precursor Powders

The porous apatite-wollastonite bioactive glass-ceramic (AW-GG) was made from nano-precursor powders derived from sol-gel process, and shaped by dipping method with polymer foam. The physical-chemical properties, bioactivity and biocompatibility of the materials were studied by means of TG, XRD, SEM, TEM and so on. The bioactivity was investigated in simulated body fluid (SBF) and the biocompatibility was evaluated by co-culturing with marrow stromal cells (MSCs). The result shows that: the particle size of the AW precursor powders is 40~100nm; porous AW GC has three-dimensional pored structure with 300~500um macropores and 2~5um micropores; the materials possess high bioactivity and biocompatibility. Porous AW GC may therefore have great potential application as bone tissue engineering scaffold.

Sol-Gel Syntheses and Characterization of BaTi4O9 and BaTiO3-Powders

1988 ◽  
Vol 121 ◽  
Author(s):  
Pradeep P. Phule ◽  
Subhash H. Rkbud
Keyword(s):  
High Purity ◽  
Sol Gel ◽  
Spherical Particles ◽  
Barium Acetate ◽  
Amorphous Precursor ◽  
Sol Gel Process ◽  
Alkoxide Precursor ◽  
Precursor Powders ◽  
Hydrolysis Of

ABSTRACTSol-gel processes for the synthesis of high purity, ultrafine BaTi4O9 and BaTiO3 powders are described. Hydrolysis of an alkoxide precursor derived from barium metal and titanium (IV) isopropoxide resulted in formation of powders consisting of ultrafine (0.2 to 1.0 μm) spherical particles. These amorphous precursor powders were converted to crystalline BaTi4O9 powders (particle size 2–3 μm) by heat treatment at 1100 C. The sol-gel process for the synthesis of BaTiOj powders utilized chemical polymerization between moisture insensitive and relatively inexpensive barium acetate and titanium (IV) isopropoxide in the presence of acetic acid. The gel to ceramic conversion was achieved by firing the gels at 1000 °C to obtain high purity, stoichiometric BaTiO3 powders. The powders were sintered to obtain relatively dense (90 % relative density) ceramic bodies.

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