English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Na-NMR spectra at 52.9 MHz have been obtained for a series of sodium sulfonate and carboxylate model compounds and for solid poly(styrene-co-styrene sulfonate) and poly(ethylene-co-methacrylic acid). Spectra of the model compounds show spin-rate independent features resembling pure quadrupolar lineshapes, but with anomalies. Na-NMR spectra of the dried ionomers are featureless and much broader than those of the models and are shifted 30–40 ppm upfield from NaCl. The sulfonated ionomer spectrum changes to a narrow line at 0 ppm upon exposure to 45% humidity at 20°C for 12 hours. The carboxylic ionomer shows no change on room temperature air exposure but 12 hours at 95°C in watersaturated air changes the spectrum markedly with some evidence for exchange among water and carboxyl groups. This type of experiment with a range of acid and Na content under rigidly controlled conditions should help elucidate the aggregation of salt groups in various ionomers.

23Na-NMR of solid state ionomers: lineshape, shift, and hydration effects