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In this paper, temperature dependence of nanoporous framework evolution process and variety of pore properties (pore volume, specific surface area (BET), and pore size) of SiO2 aerogels were characterized by FTIR, XPS, XRD, SEM, TEM, BET, BJH, etc. Results show that SiO2 aerogels treated at different temperatures all possess amorphous structure. With the increase of treated temperatures, BET values of SiO2 aerogels increase initially and then decrease, and it reaches the maximum value of 882.81 m2/g when treated at 600 ℃ for 2 h due to the addition of the nanopores and shrinkage skeleton of SiO2 aerogels. Higher temperatures may result in a framework transformation and particle growth; both factors could reduce the BET values of the aerogels. Nanoporous skeleton of SiO2 aerogels at room temperatures is composed of tetrahedron with a pore size of about 22.28 nm. Higher treated temperatures result in an increase of octahedron amount in nanoporous framework and a decrease of pore size. When treated at 1000 ℃, an approximate dense SiO2 bulk via the framework collapse and particle growth is obtained. These varieties are derived from the formed extra bonds of Si–O–Si, higher local stress, and liquid phase between particles during heat treatment process.


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A study of morphological properties of SiO2 aerogels obtained at different temperatures

Show Author's information Jin-jun LIAOaPeng-zhao GAOa( )Lin XUbJian FENGb
College of Materials Science and Engineering, Hunan University, Changsha 410082, China
Key Laboratory of New Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410082, China

Abstract

In this paper, temperature dependence of nanoporous framework evolution process and variety of pore properties (pore volume, specific surface area (BET), and pore size) of SiO2 aerogels were characterized by FTIR, XPS, XRD, SEM, TEM, BET, BJH, etc. Results show that SiO2 aerogels treated at different temperatures all possess amorphous structure. With the increase of treated temperatures, BET values of SiO2 aerogels increase initially and then decrease, and it reaches the maximum value of 882.81 m2/g when treated at 600 ℃ for 2 h due to the addition of the nanopores and shrinkage skeleton of SiO2 aerogels. Higher temperatures may result in a framework transformation and particle growth; both factors could reduce the BET values of the aerogels. Nanoporous skeleton of SiO2 aerogels at room temperatures is composed of tetrahedron with a pore size of about 22.28 nm. Higher treated temperatures result in an increase of octahedron amount in nanoporous framework and a decrease of pore size. When treated at 1000 ℃, an approximate dense SiO2 bulk via the framework collapse and particle growth is obtained. These varieties are derived from the formed extra bonds of Si–O–Si, higher local stress, and liquid phase between particles during heat treatment process.

Keywords:

silica aerogel, temperature dependence, nanoporous framework evolution, pore properties
Received: 03 March 2018 Revised: 02 May 2018 Accepted: 02 May 2018 Published: 18 December 2018 Issue date: December 2018
References(36)
[1]
QF Gao. Nano-porous silica, alumina aerogels and thermal super-insulation composites. Ph.D. Thesis. Changsha, China: National University of Defense Technology, 2009. (in Chinese)
[2]
M Rueda, LM Sanz-Moral, A Nieto-Márquez, et al. Production of silica aerogel microparticles loaded with ammonia borane by batch and semicontinuous supercritical drying techniques. J Supercrit Fluid 2014, 92: 299–310.
[3]
G Lu, X-D Wang, Y-Y Duan, et al. Effects of non-ideal structures and high temperatures on the insulation properties of aerogel-based composite materials. J Non- Cryst Solids 2011, 357: 3822–3839.
[4]
M Li, H Jiang, D Xu, et al. Low density and hydrophobic silica aerogels dried under ambient pressure using a new co-precursor method. J Non-Cryst Solids 2016, 452: 187–193.
[5]
X Tang, A Sun, C Chu, et al. A novel silica nanowire-silica composite aerogels dried at ambient pressure. Mater Design 2017, 115: 415–421.
[6]
XW Li, YY Duan, XD Wang. Impacts of structural changes of SiO2 aerogel under high temperature on its insulation performance. J Therm Sci Tech 2011, 10: 189–193.
[7]
H Maleki, L Durães, A Portugal. A new trend for development of mechanical robust hybrid silica aerogels. Mater Lett 2016, 179: 206–209.
[8]
Z Lu, Z Yuan, Q Liu, et al. Multi-scale simulation of the tensile properties of fiber-reinforced silica aerogel composites. Mat Sci Eng A 2015, 625: 278–287.
[9]
C-Y Kim, J-K Lee, B-I Kim. Synthesis and pore analysis of aerogel-glass fiber composites by ambient drying method. Colloid Surf A 2008, 313–314: 179–182.
[10]
H Wu, Y Liao, Y Ding, et al. Engineering thermal and mechanical properties of multilayer aligned fiber-reinforced aerogel composites. Heat Transfer Eng 2014, 35: 1061–1070.
[11]
J Fenech, C Viazzi, J-P Bonino, et al. Morphology and structure of YSZ powders: Comparison between xerogel and aerogel. Ceram Int 2009, 35: 3427–3433.
[12]
G Reichenauer, U Heinemann, H-P Ebert. Relationship between pore size and the gas pressure dependence of the gaseous thermal conductivity. Colloid Surf A 2007, 300: 204–210.
[13]
CL Zhou, J Yang, XY Sui, et al. Impacts of structural change of SiO2 aerogel under different time and high temperature conditions on insulation performance. Adv Ceram 2014, 5: 11–16.
[14]
D Huang, C Guo, M Zhang, et al. Characteristics of nanoporous silica aerogel under high temperature from 950 ℃ to 1200 ℃. Mater Design 2017, 129: 82–90.
[15]
N Olivi-Tran, R Jullien. Numerical simulations of aerogel sintering. Phys Rev B 1995, 52: 258.
[16]
P Chu, H Liu, Y Li, et al. Syntheses of SiC–TiO2 hybird aerogel via supercritical drying combined PDCs route. Ceram Int 2016, 42: 17053–17058.
[17]
AV Rao, ND Hegde, H Hirashima. Absorption and desorption of organic liquids in elastic superhydrophobic silica aerogels. J Colloid Interface Sci 2007, 305: 124–132.
[18]
Z Zhang, GW Scherer. Supercritical drying of cementitious materials. Cement Concrete Res 2017, 99: 137–154.
[19]
Z Shao, F Luo, X Cheng, et al. Superhydrophobic sodium silicate based silica aerogel prepared by ambient pressure drying. Mater Chem Phys 2013, 141: 570–575.
[20]
S Saeed, RMA Soubaihi, LS White, et al. Rapid fabrication of cross-linked silica aerogel by laser induced gelation. Microporous Mesoporous Mater 2016, 221: 245–252.
[21]
BA García-Torres, A Aguilar-Elguezabal, M Román-Aguirre, et al. Synthesis of silica aerogels microspheres prepared by ink jet printing and dried at ambient pressure without surface hydrophobization. Mater Chem Phys 2016, 172: 32–38.
[22]
M Shahzamain, R Bagheri, M Masoomi. Synthesis of silica-polybutadiene hybrid aerogel: The effects of reaction conditions on physical and mechanical properties. J Non-Cryst Solids 2016, 452: 325–335.
[23]
A Sutka, R Pärna, G Mezinskis, et al. Effects of Co ion addition and annealing conditions on nickel ferrite gas response. Sensor Actuat B: Chem 2014, 192: 173–180.
[24]
A Barba, C Clausell, L Nuño, et al. ZnO and CuO crystal precipitation in sintering Cu-doped Ni–Zn ferrites. II. Influence of sintering temperature and sintering time. J Eur Ceram Soc 2017, 37: 169–177.
[25]
M Nocun, K Cholewa-Kowalska, M Łączka. Structure of hybrids based on TEOS-cyclic forms of siloxane system. J Mol Struct 2009, 938: 24–28.
[26]
H Wang, Q Wu, D Cao, et al. Synthesis of SnSb-embedded carbon–silica fibers via electrospinning: Effect of TEOS on structural evolutions and electrochemical properties. Mater Today 2016, 1–2: 24–32.
[27]
J Yang, J Chen. Surface free energy and surface structure of methyl-modified silica membranes. J Mater Eng 2008, 10: 177–182.
[28]
N-H Kim, P-J Ko, Y-J Seo, et al. Improvement of TEOS- chemical mechanical polishing performance by control of slurry temperature. Microelectron Eng 2006, 83: 286–292.
[29]
Z Li, L Gong, C Li, et al. Silica aerogel/aramid pulp composites with improved mechanical and thermal properties. J Non-Cryst Solids 2016, 454: 1–7.
[30]
S He, D Huang, H Bi, et al. Synthesis and characterization of silica aerogels dried under ambient pressure bed on water glass. J Non-Cryst Solids 2015, 410: 58–64.
[31]
KSW Sing, RT Williams. Physisorption hysteresis loops and the characterization of nanoporous materials. Adsorpt Sci Technol 2004, 22: 773–782.
[32]
C Shi, S Zhang, Y Jiang, et al. High temperature properties of silica aerogel. Rare Metal Mat Eng 2016, 45: 210–213.
[33]
PB Wagh, GM Pajonk, D Haranath, et al. Influence of temperature on the physical properties of citric acid catalyzed TEOS silica aerogels. Mater Chem Phys 1997, 50: 76–81.
[34]
Z-H Li, Y-J Gong, M Pu, et al. Determination of structure of SiO2 colloidal particle by SAXS. Chin J Inorg Chem 2003, 19: 252–256.
[35]
V Morales-Flórez, NDL Rosa-Fox, M Piñero, et al. The cluster model: A simulation of the aerogel structure as a hierarchically-ordered arrangement of randomly packed spheres. J Sol-Gel Sci Technol 2005, 35: 203–210.
[36]
GC Kuczynski. Sintering Processes. Now York, 1979.
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Publication history

Received: 03 March 2018
Revised: 02 May 2018
Accepted: 02 May 2018
Published: 18 December 2018
Issue date: December 2018

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© The author(s) 2018

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