Kinetic Application: Epoxy Resin

The Curing Kinetics of an Epoxy-Based Adhesive

Epoxy-based adhesives are a group of organic materials widely used in the industry.

Problems

Problems:

  • What is the minimum temperature needed for a specified cure over a given duration of time?
  • What is the degree of curing for a given temperature program?

Solution:

The process contains reaction steps of differing directions:

  • endothermal melting at 60°C and
  • exothermal curing at 120°C-200°C.

For a process with elementary steps of differing directions, the model-free analysis does not work.

The kinetic model found by the model-based method, is in the good agreement with experimental data, and this model is used for solving the problems.

Figure 2 depicts the curing behavior for many isothermal conditions. For example, a 95% curing level is achieved at 150°C after 16.4 min, at 170°C after 9.2 min and at 200°C after 4.2 min.

Figure 3 depicts the degree of curing for a user-defined temperature profile.

Figure 1. Experimental DSC data (points) are in agreement with the results (solid line) simulated according to the kinetic model for different heating rates for both endothermal and exothermal reaction steps.
Figure 2. A curing level of 95% for isothermal conditions will be reached:
- at 150°C after 16.4 min;
- at 170°C after 9.2 min;
- at 200°C after 4.2 min
Figure 3. Degree of curing for user-defined temperature program. Final value for curing level is 97.9%.