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

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Results and Discussion 130 A time of 285 s is necessary for reaching a complete conversion in DSC. Finally a comparison of degree of conversion in function of time between MW at 1500 W and DSC at 44 ◦ C/min cure processes is presented in Figure 3.26. Figure 3.26: Comparison of degree of cure between MW at 1500 W and DSC at 44 ◦ C/min. After a time of 100 s, when the two thermal profiles are almost perfectly comparable, the ratio between the degree of cure in MW and DSC is equal to 2,37. The same analysis procedure has been repeated for the MW cure process at 2000 W correlated to a conventional DSC at 70 ◦ C/min and the results are summarized in Figure 3.27. Analogously after a time of 60 s the ratio between α MW and α DSC is equal to 13,82 . In both the cases at every time the degree of cure achieved in MW field is always higher than that obtained with conventional DSC heating. However, at time greater than 125 s for the MW cure at 1500 W, and greater than 60 s for the cure at 2000 W, the MW thermal profile are not similar with the corresponding DSC dynamic scan and therefore the direct comparison of reaction fractional conversion slightly lacks of accuracy. 130
Results and Discussion 131 Figure 3.27: Comparison of degree of cure between MW at 2000 W and DSC at 70 ◦ C/min. As predictable the ratio between the MW and DSC degree of cure is greater for the microwave process at 2000 W than that at 1500 W. 3.3.3 Dynamic Operative Conditions The microwave cure process has been studied also with the oven working in dynamic operative conditions, i.e. with moving tray, and the same type of analysis has been extended to this case. Further the microwave plant parameters, ensuring the complete conversion of the epoxy mixture 13 , without thermal degradation, have been determined. These parameters are reported in Table 3.17. The attainment of the 100% of degree of cure has been verified through a DSC dynamic scan between 0 and 220 ◦ C with heating rate of 10 ◦ C/min, performed immediatly after the quenching, on a fragment of the sample cured in these conditions. The DSC signal is illustrated in Figure 3.28. 13 Prepared as illustrated in the section 2.1.3 on page 54. 131
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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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Experimental 65 regardless of the a
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Experimental 67 • The number of t
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Experimental 69 Figure 2.11: Surfac
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Experimental 71 Figure 2.12: Repeti
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Experimental 73 From the Figure 2.1
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Experimental 75 in the centre of th
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Experimental 77 not read the water
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Page 117 and 118: Results and Discussion 117 Tables 3
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Page 163 and 164: Conclusions and Outlook 163 degree
Page 165 and 166: Appendix A A Brief History of Micro
Page 167 and 168: A Brief History of Microwave Oven 1
Page 169 and 170: Bibliography [1] W. Callister, “M
Page 171 and 172: BIBLIOGRAPHY 171 [19] P. I. Karkana
Page 173: BIBLIOGRAPHY 173 [34] K. D. V. Pras
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Kinetic Analysis and Characterization of Epoxy Resins ... - FedOA

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