Silica Aerogel Composites: Novel Fabrication Methods

149 Pages·2016·6.815 MB·English

by  Mahesh Sachithanadam, Sunil Chandrakant Joshi (auth.)

Engineering Materials
Mahesh Sachithanadam
Sunil Chandrakant Joshi
Silica
Aerogel
Composites
Novel Fabrication Methods
Engineering Materials
More information about this series at http://www.springer.com/series/4288
Mahesh Sachithanadam
Sunil Chandrakant Joshi
Silica Aerogel Composites
Novel Fabrication Methods
123
MaheshSachithanadam Sunil Chandrakant Joshi
NanyangTechnological University NanyangTechnological University
Singapore Singapore
Singapore Singapore
ISSN 1612-1317 ISSN 1868-1212 (electronic)
Engineering Materials
ISBN978-981-10-0438-4 ISBN978-981-10-0440-7 (eBook)
DOI 10.1007/978-981-10-0440-7
LibraryofCongressControlNumber:2015960417
©SpringerScience+BusinessMediaSingapore2016
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Preface
The proposed monograph is about silica aerogel composites. Silica aerogels are
known for their excellent thermal insulation properties in many industrial appli-
cations. This monograph explores novel but practical approach to fabrication of
silicaaerogelcompositessoastopushtheirapplicationboundariesbeyondthermal
insulation.
Protein-based silica aerogel composites are fabricated via inexpensive and fea-
sible methodologies. These products exhibit polymeric foam-like behavior con-
sisting of high compressibility, superhydrophobicity, and excellent strain recovery
in addition to the low thermal conductivity and density. The fabrication method-
ologiesare explained indetail and comprehended asflowcharts for reference. This
monograph will give readers another perspective to composite fabrication other
than the known traditional ones and explore the endless ways of altering the
compositionstomodifythepropertiesofthesilicaaerogelcomposites.Applications
ofthesenewandnovelcompositescouldbediverseandrangefrompharmaceutical
to aerospace to oil and gas industries.
This monograph comes with detailed schematic illustrations, experimental
techniquesemployed,andresultsandpredictivemodelstotailoraspecificproperty
for the composites. Detailed analysis of experimental results with theoretical
models and numerical simulations are one of the features of this monograph.
Schematic diagrams on the ductile ‘phenomenon’; not usually associated with
brittle silica aerogels are explained providing details on the mechanism and ratio-
naleforsuchmaterialbehavior.Themonographendsaptlywiththestudyonsound
absorption quality of the novel composites.
Mahesh Sachithanadam
Sunil Chandrakant Joshi
v
Contents
1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 What Is Aerogel??? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 How It All Started… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Uniqueness of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Aerogels Today . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Aerogels Today. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Market Outlook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Silica Aerogels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 Evolution of Silica Aerogels . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5.1 Formation of Wet Gel . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5.2 Aging and Fluid Exchange of Wet Gel. . . . . . . . . . . . . 9
2.5.3 Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3 Fabrication Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Silica Aerogel ‘Hybrid’ Composites—Developments
and Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Silica Aerogel Binder Composites . . . . . . . . . . . . . . . . . . . . . 17
3.3.1 Associated Problems . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4 Surface Chemistry of Silica Aerogel Granules . . . . . . . . . . . . . 18
3.5 Possible Routes of Binder Composite Fabrication. . . . . . . . . . . 20
3.5.1 Route 1—Resin Binders. . . . . . . . . . . . . . . . . . . . . . . 20
3.5.2 Route 2—De-Methylation of Hydrophobic Groups. . . . . 20
3.5.3 Route 3—Water Soluble Materials. . . . . . . . . . . . . . . . 21
3.6 Possible Binder Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.6.1 Gelatin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.6.2 Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
vii
viii Contents
3.7 Materials’ Property and Data. . . . . . . . . . . . . . . . . . . . . . . . . 28
3.8 Fabrication Methodologies of GSA Composites. . . . . . . . . . . . 29
3.8.1 FM Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.8.2 FD Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.9 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4 Microstructural Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.2 Hypothesis on Binder Concept. . . . . . . . . . . . . . . . . . . . . . . . 37
4.3 Chemical Analysis of Gelatin Films . . . . . . . . . . . . . . . . . . . . 38
4.4 Microstructural Examination of Silica Aerogels and Their
Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.4.1 SEM/EDX Characterization. . . . . . . . . . . . . . . . . . . . . 43
4.4.2 XPS/ESCA Surface Characterization . . . . . . . . . . . . . . 46
4.5 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5 A New Phenomenon—Brittle to Ductile Transition . . . . . . . . . . . . 51
5.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.1.1 Parametric Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.1.2 Direct Experimental Measurements . . . . . . . . . . . . . . . 55
5.2 Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.3 GSA and GSA–SDS Composites (FM Method). . . . . . . . . . . . 57
5.3.1 Compressive Stress–Strain Behavior
(FM Composites). . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.3.2 Unusual Phenomenon—Brittle to Ductile Behavior . . . . 59
5.3.3 Influence of SDS on Composite Properties from
ANOVA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.3.4 Strain Recovery Optimization via Empirical Models. . . . 64
5.4 Validation of Optimal Properties with GSA–SDS
Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.4.1 Influence of Silica Aerogel Granules on Mechanical
Properties of GSA–SDS Composites . . . . . . . . . . . . . . 69
5.5 FMWNT-Doped GSA and GSA–SDS Composites (FM). . . . . . 72
5.5.1 Influence of FMWNT on Composites. . . . . . . . . . . . . . 72
5.5.2 Experimental Result—General Trend of Stress–Strain
Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.5.3 Empirical Analysis of Various Properties . . . . . . . . . . . 75
5.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Appendix 5A—Failed Specimen Analysis (FM Method). . . . . . . . . . . 79
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Contents ix
6 Superhydrophobic and Ultralow Thermal Insulation . . . . . . . . . . . 81
6.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.1.1 Hydrophobicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.2 Thermal Conductivity Measurements . . . . . . . . . . . . . . . . . . . 84
6.3 Operating Temperature of GSA–SDS Composites . . . . . . . . . . 87
6.4 Silica Aerogel Granule Size Distribution. . . . . . . . . . . . . . . . . 88
6.5 Thermal Conductivity of Silica Aerogel Granules. . . . . . . . . . . 89
6.6 Thermal Conductivity of GSA–SDS Composites . . . . . . . . . . . 91
6.6.1 Influence of Silica Aerogel Granules on the Thermal
Conductivity of GSA–SDS (FD) Composites. . . . . . . . . 93
6.7 Thermal Conductivity of GSA–SDS/FMWNT Composites . . . . 94
6.7.1 Optimization and Validation . . . . . . . . . . . . . . . . . . . . 97
6.8 Thermal Transport Phenomenon in GSA–SDS/FMWNT
Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.9 Superhydrophobicity of FMWNT doped GSA–SDS
Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6.10 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Appendix 6A—Granule Size Distribution. . . . . . . . . . . . . . . . . . . . . 105
Appendix 6B—Optimization of Coupled Function. . . . . . . . . . . . . . . 106
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7 Acoustic Performance of Silica Aerogel Composites. . . . . . . . . . . . 109
7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.2 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.2.1 Transfer Function Method (2-microphone) . . . . . . . . . . 111
7.2.2 Inferential Transmission Loss (InTLM). . . . . . . . . . . . . 113
7.2.3 Sound Meter Measurements . . . . . . . . . . . . . . . . . . . . 115
7.3 Silica Aerogel Granules Optimization. . . . . . . . . . . . . . . . . . . 115
7.3.1 Transmission Loss of Silica Aerogel Granules. . . . . . . . 118
7.4 Acoustic Performance GSA–SDS Composites and Other
Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
7.4.1 GSA–SDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
7.4.2 GSA–SDS/FMWNT Composites . . . . . . . . . . . . . . . . . 125
7.4.3 ‘InTLM’ and Sound Meter . . . . . . . . . . . . . . . . . . . . . 127
7.5 Comparative Analysis with Other Traditional Materials. . . . . . . 128
7.5.1 Acoustic Activity. . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
7.6 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Appendix: Useful MATLAB Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Abbreviations and Symbols
Abbreviations
ANOVA Analysis of variance
APD Ambient pressure drying
CS Compressive strain
CNT Carbon nanotubes
EDX Energy dispersive X-ray spectrometer
EVA Ethylene-vinyl acetate
FD Freeze drying
FESEM Field emission scanning electron microscopy
FM Froth and mix
FMWNTs COOH functionalized multiwall carbon nanotubes
FTIR Fourier transform infrared spectroscopy
GF Gelatin film
GSA Gelatin–silica aerogel
HMWSP Hydrophobic-modified water-soluble polymers
HSZ High-strain zone
LSZ Low-strain zone
PG Porous gelatin
SA Silica aerogel
SCD Supercritical drying
SDS Sodium dodecyl sulfate
SR Strain recovery
Srate Strain rate
STP Standard temperature and pressure
TMS Trimethylsilyl
XPS/ESCA X-ray photoelectron spectroscopy/electron spectroscopy for
chemical analysis
xi