Benjamin D. Fitz

Dielectric relaxation spectroscopy of reactive network-forming polymers

Dipole dynamics in network-forming epoxy-amine formulations were investigated by dielectric relaxation spectroscopy. The unreacted liquid monomer mixture was characterized by a single αβ process at high frequencies. The αβ relaxation peak broadens with the progress of chemical reactions and separates into two peaks: α which shifts to lower frequencies and longer relaxation times, and a second peak at high frequency (megahertz range) of diminishing intensity, but essentially unchanging relaxation time. The most probable relaxation times were calculated and plotted as a function of reciprocal temperature resulting in activation energy plots. It was shown that the splitting of the αβ process into α and β processes can be brought about by either cooling a liquid without changing its structure, or continuing chemical reactions (i.e. changing the structure) while maintaining a constant temperature.