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Epoxy resins are one of the most important types of reactive glues. By changing the curing agents and/or conditions of curing, the rate of reaction is influenced.
For technical applications, the real curing behavior for certain conditions is a point of interest. Therefore, the kinetics of the curing reaction is often investigated on the basis of commercial products.
It is well known that only on the basis of several measurements, performed at different heating rates and/or different temperatures, the predictions exhibit a sufficient level of confidence. Therefore in this example 3 dynamic and 3 isothermal measurements are combined.
Measurements
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Instrument:
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NETZSCH DSC 204 Phoenix
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Heating rates
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of dynamic measurements:
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0.25, 1, 5 K/min
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Isothermal temperatures:
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137, 167, 197 ¡C
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Sample mass:
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8 .. 12 mg
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Model-free Analysis
Model-Fit
This picture demonstrates that it is possible to describe simultaneously with a high fit quality dynamic and isothermal measurements in addition to using the same kinetic model.
Prediction according to a user-defined temperature program
After definition of a temperature program, including heating up, cooling down and isothermal steps the fractional reaction is calculated, using the results of kinetic analysis.
Isothermal Prediction
The fractional reaction - at DSC by partial area - is calculated for a set of temperatures and a certain time.
Tabular report of the time for a given degree of reaction
(Partial Area) Maximum time: 200 min
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Partial
Area/%
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Temperature/¡C |
|
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120
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130
|
140
|
150
|
160
|
170
|
180
|
190
|
|
2
|
9.1
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5.4
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3.3
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2.0
|
1.3
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0.8
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0.5
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0.4
|
|
5
|
21.3
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12.7
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7.8
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4.9
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3.1
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2.0
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1.3
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0.9
|
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10
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38.3
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23.2
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14.4
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9.1
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5.9
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3.9
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2.6
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1.7
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|
20
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65.2
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40.2
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25.4
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16.3
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10.7
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7.1
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4.8
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3.3
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|
30
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87.2
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54.5
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34.8
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22.6
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15.0
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10.1
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6.9
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4.8
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40
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107.5
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67.8
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43.7
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28.6
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19.1
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13.0
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8.9
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6.2
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50
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128.1
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81.4
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52.8
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34.9
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23.5
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16.0
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11.1
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7.8
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60
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151.0
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96.6
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63.1
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42.0
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28.4
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19.5
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13.6
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9.7
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70
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179.4
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115.5
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75.9
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50.8
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34.6
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23.9
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16.8
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12.0
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80
|
|
143.0
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94.6
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63.8
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43.7
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30.4
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21.5
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15.4
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90
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197.8
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132.0
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89.7
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62.0
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43.6
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31.1
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22.4
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95
|
|
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181.2
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124.0
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86.2
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61.0
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43.7
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31.8
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98
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|
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190.0
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133.0
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94.6
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68.3
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49.9
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