Preparation and Characterization of Hydrophobic Silica Aerogel by Ambient Pressure Drying Method

2013 ◽  
Vol 544 ◽  
pp. 144-147 ◽  
Author(s):  
Hui Xu ◽  
Gui Ln Fu ◽  
Yu Qiang Guo ◽  
Jing Chun Tu ◽  
Yong Chen
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Average Pore Size ◽  
Ambient Pressure Drying ◽  
Solvent Exchange ◽  
Drying Method ◽  
Average Pore ◽  
Ft Ir ◽  
Hexane Solution

Silica aerogel has been prepared by ambient pressure drying technique using water glass as starting materials. Solvent exchange and surface modification were simultaneously conducted by immersing the wet hydrogel in EtOH/TMCS(Tri Methyl Chloro Silane)/hexane solution. The silica aerogel was obtained with the density of 0.110g•cm-3 and 95.2% porosity. The specific surface area of the silica aerogel was 472.5m2•g-1 with a average pore size distrubution of 27.5nm. FT-IR spectrum analysis showed that the surface of the silica aerogel was modified by Si-CH3 groups, which allowed the aerogel to be hydrophobic.

scholarly journals Synthesis and Characterization of Silica Aerogel from Rice Husk with Ambient Pressure Drying Method

2020 ◽  
Vol 1535 ◽  
pp. 012049
Author(s):  
Nor Fadilah Mohamad ◽  
Noor Hidayu Abdul Rani ◽  
Omar Syah Jehan Elham ◽  
Siti Hajar Anaziah Muhamad ◽  
Siti Afifah Muda ◽  
...  
Keyword(s):  
Rice Husk ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Synthesis And Characterization ◽  
Drying Method

Solvents Effects on Physicochemical Properties of Nano-Porous Silica Aerogels Prepared by Ambient Pressure Drying Method

2006 ◽  
Vol 510-511 ◽  
pp. 910-913 ◽  
Author(s):  
Seung Hun Lee ◽  
Eun A Lee ◽  
Hae Jin Hwang ◽  
Ji Woong Moon ◽  
In Sub Han ◽  
...  
Keyword(s):  
Ph Value ◽  
Ambient Pressure ◽  
Average Pore Size ◽  
Porous Silica ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Drying Method ◽  
Average Pore

Hydrophobic silica aerogels were synthesized by an ambient pressure drying method from silicic acid with a different pH value, which was prepared from sodium silicate solution (water glass). In this study we chose various hydrocarbon class solvents such as pentane, hexane, heptane, and toluene, and performed surface modification in TMCS (trimethylchlorosilane)/solvent solutions in order to improve reproducibility in aerogel production. Densities of the aerogels were about 0.1 ~ 0.3 g/cm3 , and apparent porosities were 88 ~ 96 %, depending on the processing conditions. Specific surface area was approximately 730 ~ 950 m2/g, and average pore size around 10 nm.

Fabrication and Characterization of Silica Aerogel @Polystyrene Composite Beads by Suspension Polymerization

2014 ◽  
Vol 804 ◽  
pp. 199-202
Author(s):  
Hong Wei Li ◽  
Na Lv ◽  
Pan Yan Lu ◽  
Gang Qiang Geng ◽  
Wei Wang
Keyword(s):  
Silica Aerogel ◽  
Suspension Polymerization ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Structure And Properties ◽  
Polystyrene Beads ◽  
Composite Beads ◽  
Ft Ir ◽  
Fabrication And Characterization

In this study, the powder of hydrophobic silica aerogel remaining nanopore by ambient pressure drying was successfully introduced into polystyrene beads during suspension polymerization. nanosilica powder without nanopore was also used. Pure polystyrene, silica aerogel/polystyrene (PS) and nanosilica/polystyrene beads were fabricated, respectively. The structure and properties of silica aerogel @PS composite beads were characterized by SEM, EDS, TG-DSC and FT-IR. The results of TG-DSC, FT-IR and EDS show silica aerogel is located in the PS beads, but it is difficult to be observed by SEM because of its low content. The introduction of silica and silica aerogel both decrease the transparency of PS beads. Silica aerogel loosen the microstructure of PS beads.

Synthesis and Characterization of Rice Husk Ash Derived - Silica Aerogel Beads Prepared by Ambient Pressure Drying

2016 ◽  
Vol 694 ◽  
pp. 106-110 ◽  
Author(s):  
Zulhelmi Alif Abdul Halim ◽  
Muhamad Azizi Mat Yajid ◽  
Halimaton Hamdan
Keyword(s):  
Rice Husk ◽  
Silica Aerogel ◽  
Rice Husk Ash ◽  
Ambient Pressure ◽  
Nitrogen Adsorption ◽  
Ambient Pressure Drying ◽  
Synthesis And Characterization ◽  
Gel Beads ◽  
Desorption Method

Low density silica aerogel beads were synthesized from rice husk ash via sodium silicate route. The gel beads were prepared by the ball dropping method and dried at ambient pressure after surface modification (silylation) with trimethylchlorosilane (TMCS) solution. The characteristics of porous structure of silica aerogel beads were measured by Brunauer-Emmett-Teller (BET) nitrogen adsorption and desorption method. The silica aerogel beads showed a specific surface area as high as 773 m2/g. They also displayed water-repellant effect (hydrophobic) due to silylation as revealed by Fourier transform infrared spectroscopy (FTIR).

scholarly journals Thermal Conductivity Performance of Silica Aerogel after Exposition on Different Heating under Ambient Pressure

2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0770 ◽  
Author(s):  
Israa F. Al-sharuee
Keyword(s):  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Drying Method ◽  
Insulation Property ◽  
M 10 ◽  
Basic Characteristics ◽  
Thermal Insulation Property ◽  
Quality Material

         The varied thermal conductivity (insulation) of silica aerogel with heating for different pH has been investigated, it has been depended on ambient pressure drying method in the preparing silica aerogel samples, also six different pH of samples (1, 2, 3, 7, 8 and 9) were treated under five degree of heating with (50,100,150,200 and 250) ᴼC. This technique is important to test the carry-outs hydrophobic silica to temperature without high-quality material changes in the basic characteristics. The hot-wire technique is used in this work to examine the thermal conductivity, Fourier Transform Infrared Spectroscopy (FTIR) depended to characterize the bonds and their artificial by heating. Results show that the samples affected by heating through decreasing the density leading to obtaining more insulation metal, moreover varied pH is an important role in thermal conductivity. The average thermal conductivity of all aerogel samples in this work is (0.01- 0.0061 mW m-10 C-1) this means that it is still below thermal conductivity for air equals to (0.02257) mW m-10 C-1 . Meanwhile, we concluded that the insulation property of silica aerogel is affected by heat treatment and gives it more thermal insulation property.

scholarly journals Synthesis and Characterization of Fibre Reinforced Silica Aerogel Blankets for Thermal Protection

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
S. Chakraborty ◽  
A. A. Pisal ◽  
V. K. Kothari ◽  
A. Venkateswara Rao
Keyword(s):  
Silica Aerogel ◽  
Burn Injury ◽  
Thermal Protection ◽  
Ambient Pressure ◽  
Ammonium Fluoride ◽  
Radiant Heat ◽  
Ambient Pressure Drying ◽  
Molar Ratio ◽  
Fire Hazards

Using tetraethoxysilane (TEOS) as the source of silica, fibre reinforced silica aerogels were synthesized via fast ambient pressure drying using methanol (MeOH), trimethylchlorosilane (TMCS), ammonium fluoride (NH4F), and hexane. The molar ratio of TEOS/MeOH/(COOH)2/NH4F was kept constant at 1 : 38 : 3.73 × 10−5 : 0.023 and the gel was allowed to form inside the highly porous meta-aramid fibrous batting. The wet gel surface was chemically modified (silylation process) using various concentrations of TMCS in hexane in the range of 1 to 20% by volume. The fibre reinforced silica aerogel blanket was obtained subsequently through atmospheric pressure drying. The aerogel blanket samples were characterized by density, thermal conductivity, hydrophobicity (contact angle), and Scanning Electron Microscopy. The radiant heat resistance of the aerogel blankets was examined and compared with nonaerogel blankets. It has been observed that, compared to the ordinary nonaerogel blankets, the aerogel blankets showed a 58% increase in the estimated burn injury time and thus ensure a much better protection from heat and fire hazards. The effect of varying the concentration of TMCS on the estimated protection time has been examined. The improved thermal stability and the superior thermal insulation of the flexible aerogel blankets lead to applications being used for occupations that involve exposure to hazards of thermal radiation.

Facile synthesis of silica aerogel composites via ambient-pressure drying without surface modification or solvent exchange

Vacuum ◽  
2020 ◽  
Vol 173 ◽  
pp. 109117 ◽  
Author(s):  
Dongxuan Du ◽  
Yonggang Jiang ◽  
Junzong Feng ◽  
Liangjun Li ◽  
Jian Feng
Keyword(s):  
Surface Modification ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Solvent Exchange ◽  
Facile Synthesis

Preparation and Structural Characterization of SiO2-ZrO2 Aerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2282-2285
Author(s):  
Xiao Dong He ◽  
He Xin Zhang ◽  
Yao Li ◽  
Chang Qing Hong ◽  
Jiu Peng Zhao
Keyword(s):  
Average Pore Size ◽  
Supercritical Drying ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Surface Areas ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Transmission Electron ◽  
Ft Ir ◽  
Chemical Conditions

Low density SiO2-xZrO2 aerogels with x=35wt%, 65wt%, 75wt%, 90wt%, 95wt% were prepared by CO2 supercritical drying technique with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .2H2O) by hydrolytic polycondensation under different chemical conditions. The prepared aerogels are performed by X-ray Diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR) and BET surface areas to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that the SiO2-ZrO2 areogels are the typical of nano mesopores and the average pore size is about 50 nm. The specific surface areas varied from 345.5 to 615.5 m2/g with (SBET)MAX = 615.5 m2/g with 20wt% Zirconia; Moreover a mass of Si-O-Zr bands formed in the aerogels and the formation mechanism of Si-O-Zr bands are also discussed.

scholarly journals Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient pressure

2021 ◽  
Author(s):  
Yujing Liu ◽  
Xiao Han ◽  
Balati Kuerbanjiang ◽  
Vlado K. Lazarov ◽  
Lidija Šiller
Keyword(s):  
Contact Angle ◽  
Sodium Bicarbonate ◽  
Pore Diameter ◽  
Ambient Pressure ◽  
Sodium Bicarbonate Solution ◽  
Hydrophobic Surface ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Drying Method ◽  
Average Pore

AbstractHere we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent. We prepared silica aerogels with a density and a specific surface area of 0.053 g·cm−3 and 423 m2·g−1, respectively. The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm3·g−1. Further, the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°, which indicates a super-hydrophobic surface of aerogels.

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