~1H MAS NMR Spectroscopy of Polyethylene Acrylic Acid Copolymers and Ionomers

摘要

High speed solid-state ~1H MAS NMR spectroscopy has been used to characterize a series of poly(ethylene-coacrylic acid) P(E-AA) materials where the distributions of the pendant carboxylic acid group along the polymer backbone are precisely controlled. Ionomers obtained from partial neutralization of the carboxylic acid within these P(E-AA) materials with Zn~(2+) or Li~+ were also investigated. Using a combination of ID ~1H MAS NMR and 2D ~1H MAS NMR double quantum (DQ) and NOESY correlation experiments, details about the local P(E-AA) structure were obtained. The influence of precise versus random spacing of the carboxylic acid and the impact of Li- and Zn-neutralization on the polymer structure is discussed.