Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA

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Results and Discussion 94 is focused on a comparison of the cure kinetic of epoxy system thermally and microwave crosslinked. The following section shows the dynamical, mechanical and spectroscopic characterization of the epoxy system under investigation. Finally a brief discussion about organic and metallic sensitizers will be reported. 3.1 Calorimetric Analysis The calorimetric analysis has been the first step for the characterization of the epoxy resin, used in this work. For this purpose thermo-gravimetric (TGA) and differential scanning calorimeter (DSC) measurements have been performed. 3.1.1 Thermo-gravimetric Characterization TGA measurements have been carried out on the single components of epoxy mixture for estimating the possible unwanted presence of moisture inside the prepolymer or inside the hardener agent. In the Figure 3.1 the scan of the hardener agent K 21 between room temperature up to 350 ◦ C with heating rate of 10 ◦ C/min is shown. Figure 3.1: Thermogravimetric signal of K 21 at 10 ◦ C/min. 94
Results and Discussion 95 There is a weight loss of about 2,3% around 150 ◦ C, that is attributed to moisture contained inside it. In fact this compound is lightly hygroscopic. Figure 3.2 shows the TGA of EC 57 epoxy prepolymer between room temperature up to 700 ◦ C with heating rate of 10 ◦ C/min. EC 57 is practically moisture free, in fact the weight loss at 150 ◦ C is of only 0,88%. Figure 3.2: Thermogravimetric signal of EC 57 at 10 ◦ C/min. The thermo-gravimetric analysis on epoxy mixture has instead allowed the determination of the temperature range in which carrying out the DSC calorimetric experiments and the possible presence of volatiles substances. A typical scan of fresh epoxy mixture 1 between room temperature up to 800 ◦ C with heating rate of 10 ◦ C/min is illustrated in Figure 3.3. The epoxy mixture contains a low percentage of volatiles components (about 5%). The thermal degradation of the epoxy system begins at a temperature of about 300 ◦ C. For this reason the DSC dynamic scans have been performed up to a maximum value of 220 − 250 ◦ C. 1 Obtained stirring together EC 57 and K 21 in a weight ratio of about 5:1. 95
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UNIVERSITA’ DEGLI STUDI DI NAPOLI
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3 I thank all the lecturers of PhD
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5 Microwaves are electromagnetic ra
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CONTENTS 7 1.8.1 DielectricProperti
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CONTENTS 9 4 Conclusions and Outloo
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LIST OF TABLES 11 3.2 Average value
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List of Figures 1.1 Diglycidylether
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LIST OF FIGURES 15 2.23 Onset tempe
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LIST OF FIGURES 17 3.38 Comparison
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Introduction 19 cannot be melted an
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Introduction 21 • bismaleimides;
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Introduction 23 cold solders, casti
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Introduction 25 Average Properties
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Introduction 27 In Figure 1.4 n can
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Introduction 29 ducts and it genera
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Introduction 31 tween current-carry
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Introduction 33 that describe the p
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Introduction 35 1.3.5 Lorentz Force
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Introduction 37 Figure 1.11: Electr
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Introduction 39 Even microwaves can
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Introduction 41 production requirem
Page 43 and 44: Introduction 43 fect of the electro
Page 45 and 46: Introduction 45 following different
Page 47 and 48: Introduction 47 Debye equations bas
Page 49 and 50: Introduction 49 Although these mode
Page 51 and 52: Introduction 51 materials that have
Page 53 and 54: Chapter 2 Experimental In this chap
Page 55 and 56: Experimental 55 Characteristic Note
Page 57 and 58: Experimental 57 If the oven is used
Page 59 and 60: Experimental 59 In monomodal applic
Page 61 and 62: Experimental 61 Figure 2.5: Right s
Page 63 and 64: Experimental 63 Figure 2.8: Front v
Page 65 and 66: Experimental 65 regardless of the a
Page 67 and 68: Experimental 67 • The number of t
Page 69 and 70: Experimental 69 Figure 2.11: Surfac
Page 71 and 72: Experimental 71 Figure 2.12: Repeti
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Page 83 and 84: Experimental 83 2.5 Datalogger This
Page 85 and 86: Experimental 85 same reason a wood
Page 87 and 88: Experimental 87 Material Behaviour
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Page 91 and 92: Experimental 91 2.6.3 Influence of
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Page 109 and 110: Results and Discussion 109 Kinetic
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Page 117 and 118: Results and Discussion 117 Tables 3
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Results and Discussion 145 ditions.
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Results and Discussion 147 3.23 and
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Results and Discussion 149 The T g
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Results and Discussion 151 3.6.1 St
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Results and Discussion 153 Flexural
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Results and Discussion 155 3.7.2 FT
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Results and Discussion 157 identifi
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Results and Discussion 159 This eff
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Results and Discussion 161 Also in
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Conclusions and Outlook 163 degree
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Appendix A A Brief History of Micro
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A Brief History of Microwave Oven 1
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Bibliography [1] W. Callister, “M
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BIBLIOGRAPHY 171 [19] P. I. Karkana
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BIBLIOGRAPHY 173 [34] K. D. V. Pras
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Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA

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