21885-27-8Relevant academic research and scientific papers
Phenylene ring motions in isomeric glassy epoxy networks and their contributions to thermal and mechanical properties
Tu, Jianwei,Tucker, Samuel J.,Christensen, Stephen,Sayed, Abdelwahed R.,Jarrett, William L.,Wiggins, Jeffrey S.
, p. 1748 - 1758 (2015)
Cross-linked epoxies prepared from diglycidyl ether of bisphenol A (DGEBA) exhibit substantial property differences due to isomeric structures of the diamine curatives, 3,3′- and 4,4′-diaminodiphenyl sulfone (DDS). Here, the motions of phenylene rings on both the bisphenol A (BPA) and DDS structures of the networks were investigated through solid-state NMR 2H line shape analysis to trace the molecular origins. Ring deuterated monomers, namely, DGEBA-d8, 33DDS-d8, and 44DDS-d8, were synthesized, and four deuterated networks were prepared. The line shapes of the ring motions were interpreted using a motional model that described both ring π-flips and main-chain fluctuations. The contributions of different ring motions to mechanical relaxations are elucidated, and the molecular origins of property differences are identified.
