scholarly journals Polysiloxane Hybrids via Sol-Gel Process: Effect of Temperature on Network Formation

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 677
Author(s):  
Maria Criado ◽  
Isabel Sobrados ◽  
Jesus Sanz
Keyword(s):  
Hybrid Materials ◽  
Room Temperature ◽  
Network Formation ◽  
Sol Gel ◽  
Effect Of Temperature ◽  
Molar Ratio ◽  
High Demand ◽  
Sol Gel Process ◽  
Anticorrosion Properties ◽  
The Ideal

The effect of temperature on the network formation of polysiloxane hybrids was evaluated since this type of material is currently in high demand. In the last decades, the deposition of these coatings on different substrates, mostly metals, has demonstrated anticorrosion properties. Sol-gel hybrids were prepared by mixing 3-methacryloxypropyltrimethoxysilane (MPTS) and tetramethyl orthosilicate (TMOS) with a molar ratio of 1. The formation, thickness and composition of these hybrid materials were evaluated by nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM), respectively. The results showed that the temperature plays an important role in the network formation, the total condensation degree and the total dimensionality of the hybrid materials. At room temperature, the polysiloxane hybrids presented total condensation degrees lower than 75% and a total dimensionality (dtotal) = 2.5, while those obtained at 65 °C presented total condensation degrees higher than 80% and a dtotal = 2.8. The ideal conditions to prepare polysiloxane hybrids are 65 °C for 4 h, where this shows a higher atomic percentage of Si and a greater thickness.

Optimization Sol Gel Process Parameter of CaCu3Mn4O12

2014 ◽  
Vol 548-549 ◽  
pp. 326-330
Author(s):  
A. Nurulhuda ◽  
Y. Hafizzal ◽  
A.R.M. Warikh ◽  
A. Rafidah ◽  
Y. Suhaila ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Low Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Sol Gel ◽  
Molar Ratio ◽  
Three Dimension ◽  
Sol Gel Process ◽  
Sintering Condition

The influence in optimization of processing, calcinations and sintering parameter on the physical properties and characteristic of CaCu3Mn4O12 were investigated. The stoichiometric CaCu3Mn4O12 powders were successfully prepared by the citric gel method. Dried gel with three dimension network consisted of molar ratio of [citrates/metallic ion]; 1:2 was formed. The precursor gel formed was calcined and sintered at range 400 °C to 800 °C. A single-phase CaCu3Mn4O12 fairly well densified at relative low temperature under atmospheric sintering condition. FESEM results turned out that CaCu3Mn4O12 powder particle is submicron in size and highly agglomerates due to high calcinations temperature. The smaller particle size with higher grain boundary and less of porosity were found for the sample sintered at 700 °C to 800 °C. The samples show the ‘superparamagnetism’ behavior where the M-H curves are linear with the field and have a smaller value of coercivity at room temperature. Sintering at 800 °C produced the sample with lowest Hc value due to the phenomenon of over grown magnetocrystallites, grain size and grain boundaries.

Er3+-doped Polyether/siloxane Hybrid Materials for Optoelectronics

2004 ◽  
Vol 847 ◽  
Author(s):  
S. C. Nunes ◽  
V. de Zea Bermudez ◽  
R. A. Sá Ferreira ◽  
L. D. Carlos ◽  
E. Morales ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Emission Intensity ◽  
Room Temperature ◽  
Sol Gel ◽  
Molar Ratio ◽  
Salt Composition ◽  
Concentration Effects ◽  
Gel Method ◽  
Hybrid Matrix ◽  
Covalently Bonded

ABSTRACTThe sol-gel method was employed to obtain poly(oxyethylene) (POE)/siloxane hybrids (di-ureasils) doped with erbium triflate (Er(CF3SO3)3). The host hybrid matrix employed is composed of a siliceous framework to which short POE chains are covalently bonded through urea linkages (-NH(C(=O)NH-). Xerogels with ∞ > n ≥ 5 (where n, salt composition, is the molar ratio of OCH2CH2 moieties per Er ion) were analyzed. Samples with n ≥ 20 are amorphous. Those with n > 20 are thermally stable up to about 325 °C. In the di-ureasils proposed, the Er ions are active at room temperature (RT). Concentration effects on the quenching of the 1.53 mm emission intensity (excited at 488 nm) are negligible.

UV Curable Organic-Inorganic Hybrid Materials

2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang
Keyword(s):  
Hybrid Materials ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Solution Ph ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Degradation Temperature ◽  
Sol Gel Process ◽  
The Stability ◽  
Thermal Degradation Temperature

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥

Effect of Annealing temperature on the Structural and Magnetic Properties of TbxY3-xFe5O12(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Garnet Phase ◽  
Sol Gel Process ◽  
Amorphous Structures

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

The preparation of poly(methylsilsesquioxane) network-polyimide hybrid materials by the sol-gel process and their properties

1994 ◽  
Vol 6 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Yoshitake Iyoku ◽  
Masa-aki Kakimoto ◽  
Yoshio Imai
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Tensile Modulus ◽  
Hybrid Films ◽  
Elongation At Break ◽  
Dimethyl Acetamide ◽  
Flexible Films ◽  
Sol Gel Process ◽  
Heating Up ◽  
Silicone Content

Poly(methylsilsesquixoane) network (silicone)-polyimide hybrid materials were successfully prepared by the sol-gel reaction of methyltriethoxysilane (MTES). The ethoxysilyl group in MTES was hydrolyzed and polycondensed in the solution of the polyamic acid, derived from pyromellitic dianhydride and bis(4-aminophenyl)ether, in N,N-dimethyl-acetamide (DMAc). The hybrid films were obtained by casting the reaction mixture, followed by heating up to 300°C. The hybrid materials containing 0-60wt% of silicone afforded flexible films. The films containing less than 7 wt% silicone were yellow and transparent, whereas the films with higher silicone content were yellow and opaque. Silicone particles with a diameter of around 1-10 μm were observed in the fracture surface of the hybrid films by scanning electron microscopy. Although the tensile strength and tensile modulus of the films obtained decreased with increasing silicone content. the value of the elongation at break remained at 60% up to 30% silicone content.

Indium oxide octahedrons based on sol–gel process enhance room temperature gas sensing performance

2015 ◽  
Vol 637 ◽  
pp. 55-61 ◽  
Author(s):  
Xiaohui Mu ◽  
Changlong Chen ◽  
Liuyuan Han ◽  
Baiqi Shao ◽  
Yuling Wei ◽  
...  
Keyword(s):  
Indium Oxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Sensing Performance

Organic–inorganic hybrids having a talc-like structure as suitable hosts to guest a wide range of species

2018 ◽  
Vol 47 (9) ◽  
pp. 2925-2932 ◽  
Author(s):  
J. Brendlé
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Step Method ◽  
Mild Conditions ◽  
Condensation Reactions ◽  
Wide Range ◽  
Sol Gel Process ◽  
Hydrolysis And Condensation ◽  
One Step

The sol–gel process involving hydrolysis and condensation reactions is an attractive way to form siloxane based hybrid materials since it is a one-step method performed under mild conditions.

Homogeneous phase synthesis of chitosan silica hybrid materials in ionic liquid medium and adsorption of Fe(III) from aqueous solutions

2019 ◽  
Vol 38 (9) ◽  
pp. 586-597 ◽  
Author(s):  
Ananda S. Amarasekara ◽  
Deping Wang
Keyword(s):  
Ionic Liquid ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Phase Reaction ◽  
Phase Synthesis ◽  
Homogeneous Phase ◽  
Sol Gel Process ◽  
Hydrolysis Of ◽  
Silica Hybrid ◽  
Ionic Liquid Medium

Two chitosan silica hybrid materials were prepared by a two-step process in 78–84% yields using the homogeneous phase reaction of 3-(triethoxysilyl)propyl isocyanate with chitosan dissolved in 1-n-butyl-3-methylimidazolium chloride ionic liquid (∼10% w/w), which was followed by NH4OH catalyzed hydrolysis of triethoxysilyl groups and then sol-gel process. These new hybrid materials were shown to adsorb up to about 95% of Fe3+ from 5 × 10−4 M aqueous solution at room temperature in 24 h.

scholarly journals Interlayer-free Glucose Carbonised Template Silica Membranes for Brine Water Desalination

2019 ◽  
Vol 280 ◽  
pp. 03010 ◽  
Author(s):  
Dwi Rasy Mujiyanti ◽  
Muthia Elma ◽  
Mufidah Amalia
Keyword(s):  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Water Desalination ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Nacl Solution ◽  
Silica Membranes ◽  
Salt Ions ◽  
Sol Gel Process ◽  
Free Glucose

Interlayer-free glucose carbonized template silica membranesbased on tetraethyl orthosilicate (TEOS) and glucose were successfullyprepared using an acid-base catalysed sol-gel method for artificial brinewater desalination (7.5% wt NaCl solution %) at temperatures range from25, 40 and 60 °C. These membranes calcined at 250 and 400 °C. Themembranes were fabricated through sol-gel process by using TEOS(tetraethyl orthosilicate); ethanol; nitric acid; ammonia; aquadest andglucose as a template. By molar ratio is 1: 38: 0.0007: 0.0003: 5 and0.25%; 0.5%, 1% w/v glucose as template. The results show the highestwater fluxes of 1.8, 2.2 and 4.8 kg m−2 h−1 for 25, 40 and 60 °Cdesalination process with excellent salt rejections of 99.5, 99.5 and 99.7%, respectively. It was found that the higher the NaCl solution temperature asfeed solution as well as glucose concentration (0.25% to 1% wt) astemplate attached in the silica matrixes, the higher water fluxes eventhough the salt rejection remain the same. This study demonstrates that theorganosilica membranes offered the carbonized silica mesostructuremembranes with excellent separation of water from the hydrated salt ions, particularly for processing brine salt solutions.

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