STUDY OF GLASSY STATE RING MOTIONS IN AEROSPACE EPOXY NETWORKS

摘要

Polymer composite matrices dissipate energy in the glassy state through complex molecular levelmotions including bond rotations, torsions, ring flips and etc. We have developed solid stateNMR techniques to study glassy state ring motions of aerospace epoxies to gain insights for theinfluence of sub-Tg molecular mobility upon polymer network mechanics. We have synthesizeda series of deuterated aromatic epoxies and aromatic amines to study ring motion contributions tosub-Tg transitions. Quadrupolar echo lineshape analysis and inversion recovery experiments,combined with computational simulations were used to study the ring motions. It was found thatthe phenylene rings in our systems undergo ring flipping and fast libration.