Papers by Keyword: Tetraethoxysilane

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Authors: Yasuyuki Morita, Toshiki Miyazaki, Eiichi Ishida, Chikara Ohtsuki
Abstract: So-called bioactive ceramics are used for bone-repairing owing to attractive features such as direct bone-bonding in living body. However, there is limitation on clinical applications due to their inappropriate mechanical properties performances such as higher brittleness and lower fracture toughness than natural bone. To overcome this problem, hybrid materials have been developed by modification of calcium silicate, that is basic component of bioactive ceramics, with organic polymer. It is known that bioactive ceramics bond to bone through bone-like apatite layer which is formed on their surfaces by chemical reaction with body fluid. We attempted preparation of bioactive organic-inorganic hybrids from Glucomannan that is a kind of complex polysaccharide, and calcium silicate. Hybrids were prepared from glucomannan and tetraethoxysilane (TEOS). They were treated with 1M (=mol·m-3) CaCl2 aqueous solution for 24 hours. Then ability of apatite formation on the hybrids was examined in vitro using simulated body fluid (SBF, Kokubo solution). Surface structure of the specimens was examined by thin-film X-ray diffraction (TF-XRD), scanning electron microscopic (SEM) observation. The hybrids with TEOS:Glucomannan= 1:1 to 4:1 in mass ratio formed the apatite in SBF within 3 or 7 d, when they were previously treated with CaCl2 solution.
Authors: Hong Sheng Wang, Ling Li, Chong Hai Wang, Yong Li, Qi Hong Wei
Abstract: In this study, 2.5 dimensional quartz fibers reinforced fused silica (2.5D SiO2f/SiO2) composites were prepared by in-situ solidification vacuum-assisted liquid-phase infiltration method using Si-sol and tetraethoxysilane. Composites’ tensile strength and compressive strength were tested by universal testing machine, and the microstructures of the specimen were observed by scanning electron microscopy (FEI Sirion 200). The ultimate sintering temperature was chosen by the differential thermal analysis of tetraethoxysilane gel and the effect of sintering temperature on the composites’ tensile strength. Densification behavior, mechanical properties and microstructures of the composites were investigated. The results show that tetraethoxysilane infiltration process is an efficient route for the preparation of SiO2f/SiO2 composites, after two cycles when the weight was no longer increased using Si-Sol infiltration, the density of SiO2f/SiO2 composites increases from 1.63 to 1.74g/cm3, while the tensile strength and compressive strength, respectively, increase from 31.2 to 52.7MPa and 59.0 to 129.7 MPa. And the interface de-bonding and distinct fibers pull-out of the fracture faces show that it is non-brittle fracture. The enhanced mechanism of tetraethoxysilane infiltration was also analyzed in this paper.
Authors: Mauricio Pacio, H. Juárez, T. Díaz-Becerril, E. Rosendo-Andrés, G. García-Salgado, G. Escalante, G. Ramirez
Abstract: Fluorinated silicon oxide (SiOF) films have been prepared in a conventional atmospheric pressure chemical vapor deposition (APCVD) reactor. APCVD technique utilizes tetraethoxysilane, ozone and hydrofluoric anhydride as gas sources. SiOF films are deposited by changing the temperature of deposit. Substrate holder was maintained in the temperature range of 200 to 275°C. Films were characterized based on the deposition temperature. Chemical bonding structure of the films was evaluated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and ellipsometry techniques. FTIR spectra revealed Si-F bond at about 935 cm-1. Incorporation of fluorine has a minimal contribution in the reduction of refractive index of SiOF films from 1.46 to 1.35.Therefore, the main mechanism responsible for this reduction of refractive index is the porosity generated by incorporation of fluorine atom in the SiOF films. Dielectric constant was reduced from 4.2 corresponding to that of SiO2 films, to the values in the range of 3.18 to 3.6 for SiOF films deposited by APCVD technique.
Authors: Anton S. Brichkov, Victoria Y. Brichkova, Lidia A. Egorova, Vladimir Kozik, Vladimir K. Ivanov
Abstract: The paper studies the formation of thin-film and disperse SiO2-MxOy systems (where M – Mn, Fe, Co, Ni) synthesized with sol-gel technology. The influence of metal salt on tetraethoxysilane hydrolysis and film-forming solution viscosity is considered. Dependence of the film optical properties on their composition was determined.
Authors: Feng Liao, Xing Rong Zeng
Abstract: UV curable 3-(trimethoxysilyl) propyl methacrylate MPTMS modified silica hybrid coating was prepared through sol-gel process from TEOS and MPTMS in acid medium for different ratios between TEOS and MPTMS. The structure of the hybrid coating and the formation of inorganic-organic hybrid networks were studied by FT-IR. It was found that the organic networks were formed by the polymerization of C=C bonds at 1638 cm-1. The influences of the photoinitiator content and the curing time on the curing degree of the mixture system were investigated. The results showed that the optimal photoinitiator content was 3%, and curing time was 180 s. The thermal stability of the UV cured coating was investigated by TG-DTA. The results showed that the contents of low-molecular compounds such as H2O, CH3OH, etc. were decreased in cured coatings with the increasing of the MPTMS concentration, thus significantly decreasing of the thermal weight-loss at temperature lower than 400°C.
Authors: Li Ying Guo, Jun Shi, Jun Hai He, Ji Yue Huang, Peng Cheng Huang
Abstract: Three kinds of functionalized imidazolium ionic liquid, 1-chloride (2-hydroxyethyl) -3-methyl imidazole ionic liquid [HeMIM]Cl, 1-bromide ethylamine-3-methyl imidazolium ionic liquid [AeMIM]Br and chlorinated 1-carboxyethyl-3-methyl imidazolium ionic liquid [CeMIM]Cl, were synthesized firstly. Subsequently, three kinds of supported silicon imidazolium ionic liquids were prepared from above ionic liquids with tetraethoxysilane by sol-gel method. The Chemical structure and crystal structure of the supported on silica based ionic liquids were analyzed by FTIR and XRD.
Authors: Zhong Zhou Yi, Bo Wang, Feng Rui Zhai, Zhi Peng Xie
Abstract: The self-catalytic role of zirconium n-propoxide has been investigated with respect to the synthetic parameters of ZrO2/Y2O3-CeO2 compound powders. When zirconium n-propoxide is prehydrolyzed, the gelation time is prolonged, resulting in a more transparent gel. It is found that gelation time can be shortened with a high concentration of tetraethoxysilane in the presence of a small amount of zirconium n-propoxide. On the basis of the synthetic data, a mechanism for the zirconium n-propoxide catalytic reactions has been discussed. A linear correlation between the mixing level and metal content holds up to 45 mol% of ZrO2/Y2O3 under the studied conditions.
Authors: Anton Brichkov, Viktoriya Brichkova, Lidia Egorova, Aleksandra Malchik, Vladimir Kozik
Abstract: The paper considers the formation of silicon oxides and d-metals using differential-scanning calorimetry data of the film-forming solutions hydrolysates containing tetraethoxysilane and d-metal salts. The major stages of double oxides SiO2-MxOy (where M – Mn, Fe, Co, Ni) formation, and behavior of the systems upon the application of heat are analyzed. Thermal treatment intervals which display the difference of the systems behavior depending on the metal nature were determined.
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