SOLID-STATE C-13 MAS NMR-STUDIES OF ANION-EXCHANGE RESINS AND THEIR PRECURSORS

Anion exchange resins and the corresponding precursor resins have been investigated by C-13 solid state nuclear magnetic resonance spectrosc opy. Cross-polarization, single pulse excitation (SPE), and nuclear Ov erhauser enhancement pulse sequences in combination with magic angle s pinning (MAS) techniques have been exploited. Variable temperature MAS has also been carried out in order to probe the reaction between unre acted double bonds and chloromethyl methyl ether in the presence of a Lewis acid. New resonances detected by this method have been rationali sed in structural terms. The level of secondary cross-linking (methyle ne bridging) during chloromethylation has also been determined by the use of the inherently quantitative SPE technique at low field.