Real-Time Quantification of Etherification Reactions During Cure and Postcure of Epoxy/Diamine Networks
Polymer Science and Engineering
Traditional understanding of the progress of thermoset cure is limited to a single degree of cure value related to relative results obtained in techniques such as dynamic scanning calorimetry (DSC). In this work, the development of epoxy/diamine networks was monitored, in real time, throughout cure with Fourier Transform Infrared Spectroscopy in the near infrared region (NIR). Networks cured with difunctional (DGEBF) or tetrafunctional (TGDDM) epoxy monomers were also compared in order to determine the effect of chemical gelation on final network formation. The NIR technique allows for direct quantification of functional groups directly involved in the cure of aerospace matrices. It was determined that the etherification could be monitored through the out of step consumption of epoxide and amine functional groups. This allows for the abundance of etherification throughout cure to be correlated to cure protocol. Molar absorptivity was determined to be dependent on temperature and was adjusted during NIR analysis to allow for more representative results of functional group consumption and overall network conversion. The accuracy of this method to measure network conversion was validated by use of DSC. This work establishes a means to view a complete picture of the development of epoxy-amine networks throughout cure, which allows for a more complete understanding of the effect of cure protocol on final network structure.
CAMX 2018 - Composites and Advanced Materials Expo
(2018). Real-Time Quantification of Etherification Reactions During Cure and Postcure of Epoxy/Diamine Networks. CAMX 2018 - Composites and Advanced Materials Expo.
Available at: https://aquila.usm.edu/fac_pubs/19319