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

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Results and Discussion 116 Time for the Epoxy System Complete Conversion at Different Powers P[W] t[s] 1000 350 1500 175 2000 100 Table 3.9: Time required for the complete conversion of the epoxy system during MW cure processes at different radiation powers. example the signal obtained with a fragment of the sample cured for 175 s with a power of 1500 W is illustrated in Figure 3.13. Figure 3.13: DSC dynamic scan of sample microwave cured for 175 s at 1500 W. At every power, partial microwave cure processes have been performed, for time less than that required for a complete conversion and selected in a way to obtain a representative trend of fractional degree of cure. After these time the residual enthalpy of the sample (∆H RES ) has been measured with a DSC dynamic scan between 0 and 250 ◦ Cwithasof10 ◦ C/min. These data have been listed in 116
Results and Discussion 117 Tables 3.10, 3.11 and 3.12. Residual Enthalpy versus Time for P = 1000 W Time [s] ∆H RES [J/g] 100 415,7 150 349,1 200 139,1 250 86,07 300 9,48 350 ≈ 0 Table 3.10: Residual enthalpy against time during MW cure process at 1000 W. In every case a sharp decrease of residual enthalpy is observed after a time depending on the heating rate and, therefore on the radiation power. For example in Figure 3.14 the residual enthalpy after a microwave cure process at 1500 W for 125 s is shown. During these partial crosslinking reactions the sample temperatures have been recorded every 0,5 s by datalogger 10 . For a clearer representation of the data, only the temperatures corresponding to the time, chosen for the residual enthalpy measurement, have been plotted. The thermal profile, followed by the system during the cure process at the power of 1000 W, illustrated in Figure 3.15, is not reproducible with a simple DSC dynamic scan and therefore, at least for the comparison between MW and DSC, has been discarded. While the thermal profiles during the cure at 1500 W and 2000 W are well comparable with DSC dynamic scan, respectively at 44 and 70 ◦ C/min, at least for the main part of the reaction 10 Described in the section 2.5 on page 83. 117
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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
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Introduction 43 fect of the electro
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Introduction 45 following different
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Introduction 47 Debye equations bas
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Introduction 49 Although these mode
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Introduction 51 materials that have
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Chapter 2 Experimental In this chap
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Experimental 55 Characteristic Note
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Experimental 57 If the oven is used
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Experimental 59 In monomodal applic
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Experimental 61 Figure 2.5: Right s
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Experimental 63 Figure 2.8: Front v
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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
Page 73 and 74: Experimental 73 From the Figure 2.1
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Page 77 and 78: Experimental 77 not read the water
Page 79 and 80: Experimental 79 Test number 1 2 3 4
Page 81 and 82: Experimental 81 Figure 2.19: Plot o
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
Page 89 and 90: Experimental 89 in function of the
Page 91 and 92: Experimental 91 2.6.3 Influence of
Page 93 and 94: Chapter 3 Results and Discussion Th
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Page 97 and 98: Results and Discussion 97 Figure 3.
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Page 107 and 108: Results and Discussion 107 where k
Page 109 and 110: Results and Discussion 109 Kinetic
Page 111 and 112: Results and Discussion 111 Figure 3
Page 113 and 114: Results and Discussion 113 3.3 Comp
Page 115: Results and Discussion 115 pedestal
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Page 125 and 126: Results and Discussion 125 simulate
Page 129 and 130: Results and Discussion 129 t DSC [s
Page 133 and 134: Results and Discussion 133 Using th
Page 135 and 136: Results and Discussion 135 forward
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Page 143 and 144: Results and Discussion 143 Since ev
Page 145 and 146: Results and Discussion 145 ditions.
Page 147 and 148: Results and Discussion 147 3.23 and
Page 149 and 150: Results and Discussion 149 The T g
Page 151 and 152: Results and Discussion 151 3.6.1 St
Page 153 and 154: Results and Discussion 153 Flexural
Page 155 and 156: Results and Discussion 155 3.7.2 FT
Page 157 and 158: Results and Discussion 157 identifi
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Page 161 and 162: Results and Discussion 161 Also in
Page 163 and 164: Conclusions and Outlook 163 degree
Page 165 and 166: 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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