Bismaleimide bridged silsesquioxane aerogels with excellent heat resistance: effect of sol–gel solvent polarity

Soft Matter ◽  
2020 ◽  
Vol 16 (14) ◽  
pp. 3548-3554
Author(s):  
Juan Zhao ◽  
Guanjie Zeng ◽  
Fangxin Zou ◽  
Shaohua Jiang ◽  
Yeqing Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Thermal Insulation ◽  
Sol Gel ◽  
Solvent Polarity ◽  
Good Thermal Stability ◽  
Bridged Silsesquioxane ◽  
Micro Structures

Bismaleimide bridged silsesquioxane aerogels with tailorable micro-structures exhibit superhydrophobicity, stable wettability, good compressive toughness, good thermal stability and thermal insulation.

Pd/SiO2 Organic-Inorganic Hybrid Materials by Sol-Gel Method: Preparation and Thermal Stability under H2 Atmosphere

2015 ◽  
Vol 1118 ◽  
pp. 20-27
Author(s):  
Jing Yang ◽  
Bao Song Li ◽  
Xiang Huo ◽  
Hao Xu ◽  
Hai Yun Hou
Keyword(s):  
Thermal Stability ◽  
Calcination Temperature ◽  
Hybrid Materials ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Good Thermal Stability ◽  
Pd Doping

Pd/SiO2 organic-inorganic hybrid materials were prepared by adding PdCl2 into methyl-modified silica sol. The Pd/SiO2 hybrid materials were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of calcination temperature and Pd-doping on the phase transition of Pd element and the thermal stability of CH3 group in the Pd/SiO2 organic-inorganic hybrid materials were investigated. The results showed that the reduced metallic Pd0 exhibits good thermal stability under H2 atmosphere in the calcination process. Pd element in noncalcined Pd/SiO2 materials exists in PdCl2 form, calcination at 200 °C in a H2 atmosphere produces some metallic Pd0 and calcinations at 350 °C results in the complete transformation of Pd2+ to metallic Pd0. With the increase of calcination temperature, the Pd0 particle sizes increase and the hydrophobic Si−CH3 bands decrease in intensity. As the calcination temperature is greater than or equal to 350 °C, the loading of metallic Pd0 nearly has no influence on the chemical structure but, with the increase of Pd content, the formed Pd0 particle size increases. To keep the hydrophobicity of Pd/SiO2 membrane materials, the optimal calcination temperature is about 350 °C under H2 atmosphere.

Hybrid Nanocomposite Coatings for Application in Construction Materials: Tribological Study

2009 ◽  
Vol 151 ◽  
pp. 234-239 ◽  
Author(s):  
Celia Silvestre ◽  
M.J. López-Tendero ◽  
Manuel Cruz-Yusta ◽  
Noelia Baeza ◽  
Celia Guillem ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Sol Gel ◽  
Construction Materials ◽  
Hybrid Coatings ◽  
Nanocomposite Coatings ◽  
Hybrid Nanocomposite ◽  
Simultaneous Formation ◽  
Inorganic Hybrid ◽  
Good Thermal Stability ◽  
Construction Products

The Nanocomposite group of AIDICO and the Nanomaterials Group of University of Valencia collaborate in the research of new organic-inorganic hybrid materials with application in construction products. Tribological properties and good thermal stability are some of the required specifications for such applications. Some hybrid coatings based on simultaneous formation of epoxy and silica networks are introduced in this work. Elastic modulus and hardness obtained from TDMA analyses and indentation techniques, together with thermal stability by TGA, are the main properties analysed in order to fulfil the requirements for construction coating applications. New routes for obtaining these coatings based on sol-gel have been explored.

scholarly journals Ethylene-bridged polysilsesquioxane/hollow silica particle hybrid film for thermal insulation material

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 24968-24975
Author(s):  
Satoru Tsukada ◽  
Yuki Nakanishi ◽  
Takashi Hamada ◽  
Kenta Okada ◽  
Susumu Mineoi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Insulation ◽  
Silica Particle ◽  
Hybrid Film ◽  
Sol Gel ◽  
Insulation Material ◽  
Hybrid Films ◽  
Hollow Silica ◽  
Bridged Polysilsesquioxane ◽  
Hollow Silica Particles

Ethylene-bridged polysilsesquioxane/hollow silica particle hybrid films were prepared by the sol–gel reaction. The hybrid film containing hollow silica particles exhibited good thermal insulation properties and thermal stability.

scholarly journals Preparation and Characterization of Transparent Polyimide–Silica Composite Films Using Polyimide with Carboxylic Acid Groups

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 489 ◽  
Author(s):  
Kwan Moon ◽  
Boknam Chae ◽  
Ki Kim ◽  
Seung Lee ◽  
Young Jung
Keyword(s):  
Thermal Stability ◽  
Carboxylic Acid ◽  
Coefficient Of Thermal Expansion ◽  
Condensation Reaction ◽  
Sol Gel ◽  
Composite Films ◽  
Amic Acid ◽  
Good Thermal Stability ◽  
Silica Composite ◽  
Sol Gel Process

Polyimide (PI) composite films with thicknesses of approximately 100 µm were prepared via a sol–gel reaction of 3-aminopropyltrimethoxysilane (APTMS) with poly(amic acid) (PAA) composite solutions using a thermal imidization process. PAA was synthesized by a conventional condensation reaction of two diamines, 3,5-diaminobenzoic acid (DABA), which has a carboxylic acid side group, and 2,2′-bis(trifluoromethyl)benzidine (TFMB), with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc). The PAA–silica composite solutions were prepared by mixing PAA with carboxylic acid side groups and various amounts of APTMS in a sol–gel process in DMAc using hydrochloric acid as a catalyst. The obtained PI–silica composite films showed relatively good thermal stability, and the thermal stability increased with increasing APTMS content. The optical properties and in-plane coefficient of thermal expansion (CTE) values of the PI–silica composite films were investigated. The CTE of the PI–silica composite films changed from 52.0 to 42.1 ppm/°C as the initial content of APTMS varied. The haze values and yellowness indices of the composite films increased as a function of the APTMS content.

scholarly journals Facile Synthesis of Methylsilsesquioxane Aerogels with Uniform Mesopores by Microwave Drying

2019 ◽  
Author(s):  
Xingzhong Guo ◽  
Jiaqi Shan ◽  
Wei Lei ◽  
Ronghua Ding ◽  
Yun Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Production Efficiency ◽  
Sol Gel ◽  
Microwave Drying ◽  
Remarkable Effect ◽  
Good Thermal Stability ◽  
Pore Structures ◽  
Sol Gel Process ◽  
20 Nm ◽  
Uniform Mesopores

Methylsilsesquioxane aerogels with uniform mesopores have been facilely prepared via a sol–gel process followed by microwave drying with methyltrimethoxysilane (MTMS) as precursor, hydrochloric acid (HCl) as catalyst, water and methanol as solvents, hexadecyltrimethylammonium chloride (CTAC) as surfactant and template and propylene oxide (PO) as gelation agent. The microstructure, chemical composition and pore structures of the resultant MSQ aerogels were investigated in detail to achieve controllable preparation of MSQ aerogels, and the thermal stability of MSQ aerogels was also analyzed. The gelation agent, catalyst, solvent and microwave power have important roles on pore structures of MSQ aerogels. Meanwhile, microwave drying method is found to not only have a remarkable effect on improving production efficiency, but also be conducive to avoid the collapse of pore structure especially micropores during drying. The resulting MSQ aerogel microwave-dried at 500 W possesses a specific surface area up to 821 m2/g and a mesopore size of 20 nm, and displays good thermal stability.

scholarly journals Preparation and Characteristics of Microencapsulated Lauric Acid as Composite Thermal Energy Storage Materials

2019 ◽  
Vol 26 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Yanghua CHEN ◽  
Yuan LIU ◽  
Zhaohe WANG
Keyword(s):  
Thermal Stability ◽  
Energy Storage ◽  
Lauric Acid ◽  
Sol Gel ◽  
Heat Sinks ◽  
Core Material ◽  
Energy Storage Materials ◽  
Good Thermal Stability ◽  
Infrared Spectrometer ◽  
Ft Ir

A novel microencapsulated phase change material was prepared by sol-gel method using lauric acid (LA) as core material and titanium dioxide (TiO2) as shell material. The composites were characterized by field emission scanning electron microscope (FE-SEM), Fourier transformation infrared spectrometer (FT-IR), differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The results of the FE-SEM and FT-IR indicated that LA was well coated in the shell of TiO2 and no chemical reaction occurred between them. The results of the DSC denoted that the composites with 43.5 % encapsulation ratio of the LA melted at 44.39 ℃ with the melting enthalpy of 67.54 J/g and solidified at 43.64 ℃ with the solidification enthalpy of 65.17 J/g. The results of the TGA signified that the thermal stability and fire resistance of the microcapsules were greatly enhanced under the protection barrier of TiO2. The thermal decomposition of the microencapsulated LA with TiO2 shell hardly occurred under 200 ℃. That is to say, the composites possess good thermal stability in the operating temperature range. In conclusion, the prepared microencapsulated composites can be incorporated into solar energy storage like solar air heaters and into electronic devices as heat sinks.

scholarly journals Facile Synthesis of Methylsilsesquioxane Aerogels with Uniform Mesopores by Microwave Drying

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 375 ◽  
Author(s):  
Xingzhong Guo ◽  
Jiaqi Shan ◽  
Wei Lei ◽  
Ronghua Ding ◽  
Yun Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Production Efficiency ◽  
Sol Gel ◽  
Microwave Drying ◽  
Remarkable Effect ◽  
Good Thermal Stability ◽  
Pore Structures ◽  
Sol Gel Process ◽  
20 Nm ◽  
Uniform Mesopores

Methylsilsesquioxane (MSQ) aerogels with uniform mesopores were facilely prepared via a sol–gel process followed by microwave drying with methyltrimethoxysilane (MTMS) as a precursor, hydrochloric acid (HCl) as a catalyst, water and methanol as solvents, hexadecyltrimethylammonium chloride (CTAC) as a surfactant and template, and propylene oxide (PO) as a gelation agent. The microstructure, chemical composition, and pore structures of the resultant MSQ aerogels were investigated in detail to achieve controllable preparation of MSQ aerogels, and the thermal stability of MSQ aerogels was also analyzed. The gelation agent, catalyst, solvent, and microwave power have important roles related to the pore structures of MSQ aerogels. Meanwhile, the microwave drying method was found to not only have a remarkable effect on improving production efficiency, but also to be conducive to avoiding the collapse of pore structure (especially micropores) during drying. The resulting MSQ aerogel microwave-dried at 500 W possessed a specific surface area up to 821 m2/g and a mesopore size of 20 nm, and displayed good thermal stability.

scholarly journals Synthesis and photocatalytic properties of Sn–TiO2 nanomaterials

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060018
Author(s):  
E. M. Bayan ◽  
T. G. Lupeiko ◽  
L. E. Pustovaya ◽  
M. G. Volkova
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Sol Gel ◽  
Rutile Phase ◽  
Photocatalytic Properties ◽  
Light Activation ◽  
X Ray ◽  
Tio2 Nanomaterials ◽  
Visible Light Activation ◽  
Thermal Stability Of

Sn-doped TiO2 nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20[Formula: see text]mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5[Formula: see text]mol.% of Sn.

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