Ab initio calculations of possible γ-gauche effects in the ¹³C-NMR for methine and carbonyl carbons in precise polyethylene acrylic acid copolymers.
نویسنده
چکیده
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.
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عنوان ژورنال:
- Molecules
دوره 18 8 شماره
صفحات -
تاریخ انتشار 2013