Calorimetric and Rheological Measurements of Three Commercial Thermosetting Prepreg Epoxies
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Date
2006-05-01Author
Mitch Hargis
Brian P. Grady
Levent Aktas
Krishnasumanth R. Bomireddy
Steve Howsman
M. Cengiz Altan
Tom Rose
Hans Rose
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Abstract
The cure kinetics of three different thermosetting resins are investigated using differential scanning calorimetry and oscillatory shear rheometry. For the latter, two different types of plates are used, smooth plates and grooved plates; the latter are used to improve sample–plate contact. In addition, oscillatory compression rheology is used; however, machine compliance prevents accurate measurements at high conversions. A fractional conversion is defined based on the maximum storage modulus achieved at a given temperature, and is compared to the fractional conversion calculated from enthalpy measurements. As expected, the rates of reaction derived from these fractional conversions are very different for calorimetry and rheometry. However, the rates of reaction using the two types of plates are identical, although the grooved plates give much more reproducible storage moduli. A number of previously used mathematical expressions are employed to fit the calorimetric and rheological data, and the activation energies calculated from these fits are compared.
Citation
Hargis, M., Grady, B. P., Aktas, L., Bomireddy, K. R., Howsman, S., Altan, M. C., . . . Rose, H. (2006). Calorimetric and Rheological Measurements of Three Commercial Thermosetting Prepreg Epoxies. Journal of Composite Materials, 40(10), 873-897. doi: 10.1177/0021998305056380