Chemistry Commons^™

Polymer Chain Dynamics In Epoxy Based Composites As Investigated By Broadband Dielectric Spectroscopy, Mohammad K. Hassan, Samuel James Tucker, Ahmed Abukmail, Jeffrey S. Wiggins, Kenneth A. Mauritz

Faculty Publications

Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 3,3′- and 4,4′-diaminodiphenyl sulfone isomer crosslinkers. Secondary relaxations and the glass transitions of resultant networks were probed using broadband dielectric spectroscopy (BDS). A sub-T_g γ relaxation peak for both networks shifts to higher frequencies (f) with increasing temperature in Arrhenius fashion, both processes having the same activation energy and being assigned to phenyl ring flipping in DGEBA chains. A β relaxation is assigned to local motions of dipoles that were created during crosslinking reactions. 4,4′-based networks exhibited higher T_g relative to 3,3′-based …