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Comparison of Oxygen Gauche Effects in Poly(Oxyethylene) and Poly(ethylene terephtylene) Based on Quantum Chemistry CalculationsThe so-called oxygen gauche effect in poly(oxyethylene) (POE) and its model molecules such as 1,2-dimethoxyethane (DME) and diglyme (CH3OC2H4OC2H4OCH3) is manifested in the preference for gauche C-C bond conformations over trans. This has also been observed for poly(ethylene terephthalate) (PET). Our previous quantum chemistry calculations demonstrated that the large C-C gauche population in DME is due, in part, to a low-lying tg +/- g+ conformer that exhibits a substantial 1,5 CH ... O attraction. New calculations will be described that demonstrate the accuracy of the original quantum chemistry calculations. In addition, an extension of this work to model molecules for PET will be presented. It is seen that the C-C gauche preference is much stronger in 1,2 diacetoxyethane than in DME. In addition, there exist low-lying tg +/- g+/- and g+/-g+/-g+/- conformers that exhibit 1,5 CH ... O attractions involving the carbonyl oxygens. It is expected that the -O-C-C-O- torsional properties will be quite different in these two polymers. The quantum chemistry results are used to parameterize rotational isomeric states models (RIS) and force fields for molecular dynamics simulations of these polymers.
Document ID
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Jaffe, Richard
(NASA Ames Research Center Moffett Field, CA United States)
Han, Jie
(MRJ Technology Solutions, Inc. Moffett Field, CA United States)
Yoon, Do
(International Business Machines Corp. San Jose, CA United States)
Langhoff, Stephen R.
Date Acquired
August 20, 2013
Publication Date
January 1, 1997
Subject Category
Inorganic, Organic And Physical Chemistry
Meeting Information
Meeting: American Chemical Society Meeting
Location: San Francisco, CA
Country: United States
Start Date: April 13, 1997
End Date: April 17, 1997
Sponsors: American Chemical Society
Funding Number(s)
PROJECT: RTOP 242-80-01
Distribution Limits
Work of the US Gov. Public Use Permitted.

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