Figures & Tables. 1. Introduction: Composites & A Selective History of CNT Reinforced Composites

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1 Figures & Tables 1. Introduction: Composites & A Selective History of CNT Reinforced Composites Fig. 1.1 Plywood-A Composite...2 Fig. 1.2 Aspect ratio measurement of different shape fillers 7 Fig. 1.3 Distribution of carbon fillers w.r.t their size 9 Fig. 1.4(a) Structure of diamond..11 Fig. 1.4(b) Structure of graphite..11 Fig. 1.5(a) C 60 fullerene 13 Fig. 1.5(b) C 70 fullerene 13 Fig. 1.5(c) Curvature in fullerene 13 Fig. 1.6 Graphene Layer...14 Fig. 1.7 Rolling up of graphene into SWCNT Fig. 1.8(a) A SWCNT 16 Fig. 1.8(b) A MWCNT..16 Fig. 1.9 End cap & body structure of SWCNT...16 Fig Different Schemes of rolling of graphene to form SWCNT 17 Fig. 1.11(a) Formation of armchair, zigzag & armchair CNT from graphene.18 Fig. 1.11(b) Structure of armchair, zigzag & armchair SWCNT...18 Fig. 1.12(a) Bended and twisted structures of CNT 19 Fig. 1.12(b) HRTEM images of bended MWCNT & SWCNT 19 Fig SEM & TEM images of carbon black.. 28 Fig Structure of PAN...28 Fig. 1.15(a) Structure of carbon fibre..29 Fig. 1.15(b) Carbon fibre fabric...29 Fig General trend of Electrical Conductivity of MWCNT composites..33 Fig Different molecules of catalyst Fe entrapped in CNT.35 Fig TEM image showing entrapped catalyst..35 [xv]

2 Fig SEM image of entangled MWCNT...43 Fig Different functional groups attached on CNT surface Synthesis, Characterization & Measurements Fig. 2.1 Schematic diagram of CVD experimental set-up. 56 Fig. 2.2 Experimental setup of CVD for synthesis of MW CNT 56 Fig. 2.3 Schematic diagram of Arc- Discharge set-up 57 Fig. 2.4 Experimental setup of Arc- Discharge for synthesis of MW CNT 58 Fig.2.5 Reflux set-up for treatment of MWCNT.60 Fig.2.6 Electron beam-specimen interaction.. 62 Fig. 2.7 LEO-440 Scanning Electron Microscope..63 Fig. 2.8(a) Schematic Diagram of TEM.64 Fig. 2.8(b) G2 F30 STwin HRTEM Fig. 2.9(a) Scheme of XRD...66 Fig. 2.9(b) D-8 ADVANCE X-Ray Diffractometer..66 Fig Schematic diagram of UV-Vis Spectrometer 68 Fig Shimazdu UV-1601 Spectrophotometer Fig Nicolet 5700 FTIR spherometer...71 Fig A general DSC curve showing glass transistion temperature (T g ) Crystalline temperature (T c ) and melting temperature (T m ) Fig Mettler Toledo 851 e used for DSC and TGA Fig Direct CNT Dispersionby Magnetic Stirring...76 Fig CNT Dispersion by Ultrasonication.76 Fig Three point bend method for flexural strength Fig Four point bend method for flexural strength.79 Fig INSTRON Fig Keithley 224 programmable Current Source and Keithley 197 Auto ranging digital micro Voltmeter..81 Fig Reflection & transmission of waves through a sample...82 [xvi]

3 Fig Schematc diagram of a vector analyzer 83 Fig Agilent E8362B Vector Network Analyzer Mechanical Properties of CNT-Epoxy Composites Fig. 3.1(a) Di-Glycidyl ether of Bisphenol A(DGEBA)...84 Fig. 3.1(b) Triethylene Tetramine (TETA).. 84 Fig. 3.1(c) Novalac Phenol...84 Fig. 3.2(a) Scheme D1 of composite formation..90 Fig. 3.2(b) Scheme D2 of composite formation...90 Fig. 3.3 UV-Vis spectra of dispersed MWCNT solution with different sonication time in solvent.92 Fig. 3.4 UV-Vis spectra of MWCNT dispersed in epoxy.92 Fig. 3.5 FTIR of as produced & functionalized MWCNT..93 Fig. 3.6 TGA curves of as produced & functionalized MWCNT...94 Fig. 3.7 HRTEM images of (a) o-mwcnt,(b) a-mwcnt, (c) t-mwcnt...95 Fig. 3.8(a) Variation in FS of the composites with MWCNT concentration prepared by using dispersion technique D1.96 Fig. 3.8(b) Variation in FS of the composites with MWCNT concentration prepared by using dispersion technique D Fig. 3.9 Reaction mechanism for a-mwcnt with epoxy resin..97 Fig Reaction mechanism for t-mwcnt with epoxy resin Fig. 3.11(a) FTIR of uncured epoxy and 0.3 wt% MWCNT (o-mwcnt, a-mwcnt, t-mwcnt)-epoxy Fig. 3.11(b) FTIR of cured epoxy Fig. 3.12(a) SEM image of fractured surfaces of o-mwcnt (0.3 wt.-%) epoxy Fig. 3.12(b) SEM image of fractured surfaces of a-mwcnt (0.3 wt.-%) epoxy [xvii]

4 Fig. 3.12(c) SEM image of fractured surfaces of t-mwcnt (0.3 wt.-%) epoxy Fig. 3.12(d) SEM image of fractured surfaces of o-mwcnt (0.5 wt-%) epoxy Fig. 3.13(a) SEM image of fractured surfaces of o-mwcnt (0.3 wt.-%) epoxy Fig. 3.13(b) SEM image of fractured surfaces of a-mwcnt (0.3 wt.-%) epoxy Fig. 3.13(c) SEM image of fractured surfaces of t-mwcnt (0.3 wt.-%) epoxy Fig. 3.13(d) SEM image of fractured surfaces of o-mwcnt (0.5 wt-%) epoxy Fig. 3.14(a) Variation in FM of the composites with MWCNT concentration prepared by using dispersion technique D Fig. 3.14(b) Variation in FM of the composites with MWCNT concentration prepared by using dispersion technique D Fig. 3.15(a) Reaction mechanism shows curing of epoxy by novalac phenol..105 Fig. 3.15(b) Reaction mechanism shows curing of epoxy by novalac phenol with a- MWCNTs.105 Fig Variation in FS of the composites with MWCNT concentration prepared by using novalac phenol as hardener 106 Fig Variation in FM of the composites with MWCNT concentration prepared by using novalac phenol as hardener.107 Fig. 3.18(a) SEM micrographs of fractured surfaces of o-mwcnt (0.4 wt.-%) epoxy Fig. 3.18(b) SEM micrographs of fractured surfaces of a-mwcnt (0.4 wt.-%) epoxy Fig. 3.18(c) SEM micrographs of fractured surfaces of o-mwcnt (2 wt.-%) epoxy [xviii]

5 Fig. 3.18(d) SEM micrographs of fractured surfaces of a-mwcnt (2 wt.-%) epoxy Table. 3.1 Flexural strength and flexural modulus of MWCNT epoxy composites reported recently by different authors Electrical Properties & EMI Shielding of CNT-Epoxy Composites Fig. 4.1(a) Variation in electrical conductivity of the composites with o-mwcnt concentration prepared by using TETA as hardener Fig. 4.1(b) Variation in electrical conductivity of the composites with a-mwcnt concentration prepared by using TETA as hardener 114 Fig. 4.2 Network formation in high and low aspect ratio CNTs..116 Fig. 4.3(a) SEM image measures the long length of o-mwcnt bundles Fig. 4.3(b) SEM image confirming long length of o-mwcnts Fig. 4.3(c) TEM image showing variation in diameter of o-mwcnts Fig. 4.4(a) SEM of a-mwcnts shows opening of bundles..119 Fig. 4.4(b) SEM of a-mwcnts showing their large length Fig. 4.4(c) TEM image showing variation in diameter of a-mwcnts Fig. 4.5(a) SE of 2 wt% o-mwcnt composite..122 Fig. 4.5(b) SE of 5 wt% o-mwcnt composite..122 Fig. 4.5(c) SE of 2 wt% a-mwcnt composite..122 Fig. 4.5(d) SE of 5 wt% a-mwcnt composite..122 Fig. 4.6(a) Dependence of SE R on..123 Fig. 4.6(b) Dependence of SE A on..123 Fig. 4.7(a) Variation in electrical conductivity of the composites with o-mwcnt concentration prepared by using novalac as hardener 124 Fig. 4.7(b) Variation in electrical conductivity of the composites with a-mwcnt concentration prepared by using novalac as hardener.124 [xix]

6 Fig. 4.8(a) Total SE of o-mwcnt composites..126 Fig. 4.8(b) Total SE of a-mwcnt composites.126 Fig. 4.9(a) Absorption SE of o-mwcnt composites Fig. 4.9(b) Absorption SE of a-mwcnt composites Fig. 4.9(c) Reflection SE of o-mwcnt composites..127 Fig. 4.9(d) Reflection SE of a-mwcnt composites.127 Fig. 4.10(a) Dependence of SE R on Fig. 4.10(b) Dependence of SE A on 128 Table. 4.1 Aspect Ratio measurements of o-mwcnt & a-mwcnt Table The elemental composition of o-mwcnt and a-mwcnt Table. 4.3 Comparison of Electrical Conductivity for TETA & Novalac cured Epoxy MWCNT composites CNT-Phenol Composites With High Filler Contents- Bucky Paper Route Fig. 5.1(a) Naked eye view of MWCNT Bucky paper 132 Fig. 5.1(b) SEM image of MWCNT Bucky paper. 132 Fig. 5.2 Scheme of composite preparation from Bucky paper laminates 132 Fig. 5.3 SEM images of resin impregnated Bucky paper laminates 133 Fig. 5.4 Variation in FS of the composites with MWCNT concentration 134 Fig. 5.5 Variation in FM of the composites with MWCNT concentration Fig. 5.6 Variation in electrical conductivity of the composites with MWCNT concentration..136 Fig. 5.7 Repeated multiple reflections from layers 138 Fig. 5.8 Total SE as a function of frequency with varying MWCNT concentration Fig. 5.9 Absorption SE as a function of frequency with varying MWCNT concentration [xx]

7 Fig Reflection, Absorption and Total SE of 50 wt% loaded MWCNT composite Mechanical & Electrical Properties of CNT- Thermoplastic Composites Fig. 6.1 Ehtylene polymerize to form polyethylene 143 Fig. 6.2(a) SEM of 2wt% MWCNT-LDPE nanocomposites film.146 Fig. 6.2(b) SEM of 5wt% MWCNT-LDPE nanocomposites film.146 Fig. 6.2(c) SEM of 10wt% MWCNT-LDPE nanocomposites film Fig. 6.3 XRD scans of LDPE, MWCNT & MWCNT-LDPE nanocomposites Fig. 6.4 Variation of FWHM with MWCNT loading Fig. 6.5DSC curves LDPE & MWCNT-LDPE nanocomposites..149 Fig. 6.6 TGA of LDPE and MWCNT-LDPE nanocomposites.150 Fig. 6.7 Variation of electrical conductivity with MWCNT loading 151 Fig. 6.8 Total SE of MWCNT-LDPE nanocomposites measured in Ku band.153 Fig. 6.9(a) Absorption SE of LDPE-MWCNT composites 154 Fig. 6.9(b) Reflection SE of LDPE-MWCNT composites.154 Fig. 6.10(a) Plot of SE A versus (σ) 1/ Fig. 610(b) Plot of SE R versus log( σ) 154 Table. 6.1 DSC characteristics of LDPE and LDPE/MWCNT nanocomposites.149 Table. 6.2 Electrical conductivity of MWCNT-LDPE composites reported by several author 152 [xxi]