Ab Initio Calculations of Possible γ-Gauche Effects in the 13C-NMR for Methine and Carbonyl Carbons in Precise Polyethylene Acrylic Acid Copolymers

Journal Article · Mon Jul 29 04:00:00 EDT 2013 · Molecules

DOI:https://doi.org/10.3390/molecules18089010· OSTI ID:1081505

Alam, Todd

The impacts of local polymer chain conformations on the methine and carbonyl 13C-NMR chemical shifts for polyethylene acrylic acid p(E-AA) copolymers were predicted using ab initio methods. Using small molecular cluster models, the magnitude and sign of the γ-gauche torsional angle effect, along with the impact of local tetrahedral structure distortions near the carbonyl group, on the 13C-NMR chemical shifts were determined. These 13C-NMR chemical shift variations were compared to the experimental trends observed for precise p(E-AA) copolymers as a function acid group spacing and degree of zinc-neutralization in the corresponding p(E-AA) ionomers. These ab initio calculations address the future ability of 13C-NMR chemical shift variations to provide information about the local chain conformations in p(E-AA) copolymer materials.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1081505
• Report Number(s): SAND2013--4450J; 455982
• Journal Information: Molecules, Journal Name: Molecules Journal Issue: 8 Vol. 18; ISSN MOLEFW; ISSN 1420-3049
• Publisher: MDPI
• Country of Publication: United States
• Language: English

Related Subjects

13C-NMR
36 MATERIALS SCIENCE
ab initio
carbonyl
chemical shift
methine
trans-gauche
γ-gauche