H-1 MAS NMR AND 2-DIMENSIONAL NUCLEAR OVERHAUSER ENHANCEMENT SPECTROSCOPY IN HYDROGELS

The combination of H-1 magic angle spinning (MAS) n.m.r. and two-dimen sional nuclear Overhauser enhancement spectroscopy (NOESY) is shown to be readily applicable to hydrogels. This is demonstrated in the super absorbing polymer, hydrolysed starch-g-poly(acrylonitrile), which read ily responds to hydration. Enhanced molecular mobility of the polymer is directly revealed by polymer-polymer NOESY connectivities. The two- dimensional experiment also reveals the presence of an efficient cross -relaxation mechanism between the water of hydration and the polymer.