- Phenylene ring motions in isomeric glassy epoxy networks and their contributions to thermal and mechanical properties
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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.
- Tu, Jianwei,Tucker, Samuel J.,Christensen, Stephen,Sayed, Abdelwahed R.,Jarrett, William L.,Wiggins, Jeffrey S.
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p. 1748 - 1758
(2015/03/31)
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- Synthesis of deuterated 4, 4′-diaminodiphenylsulfone (Dapsone) and related analogs
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A general scheme tor the synthesis ot 4,4′-diaminodiphenylsulfone-d5 (Dapsone) from aniline-d5 is described. The method may have general application and the preparation of the related analogs, 4,4′-dimethylaminodiphenyl sulfone from aniline-d5 and 4,4′-dimethoxydiphenyl sulfone from phenol-d5, is also described. Copyright
- Gannett, Peter M.,Johnson II, Edward M.,Grimes, Michael A.,Myers, Alan L.,Deavers III, Robert E.,Tracy, Timothy S.
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p. 107 - 114
(2007/10/03)
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