Curing of Epoxy Resin

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
Instruments:NETZSCH DSC 204 Phoenix
Heating rates of dynamic measurements: 0.25, 1, 5 K/min 
Isothermal temperatures: 137, 167, 197 ¡C
Sample mass: 8 .. 12 mg

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

Partial
Area/%
Temperature/¡C
120130140150160170180190
29.15.43.32.01.30.80.50.4
521.312.77.84.93.12.01.30.9
1038.323.214.49.15.93.92.61.7
2065.240.225.416.310.77.14.83.3
3087.254.534.822.615.010.16.94.8
40107.567.843.728.619.113.08.96.2
50128.181.452.834.923.516.011.17.8
60151.096.663.142.028.419.513.69.7
70179.4115.575.950.834.623.916.812.0
80143.094.663.843.730.421.515.4
90197.8132.089.762.043.631.122.4
95181.2124.086.261.043.731.8
98190.0133.094.668.349.9