High-resolution N.M.R. of Solids

High-resolution N.M.R. of Solids.— The period under review has seen substantial progress in the application of solid-state high resolution n.m.r. techniques to polymers. The techniques comprise multiple-pulse sequences (MP), dipolar-decoupling (DD), and magic-angle sample rotation (MAR). In addition, cross-polarization (CP) may be used to enhance weak C resonances. These experiments provide both dynamic and structural information as do conventional broadline measurements, but the resolution of individual resonances provides a detailed description of molecular behaviour at the monomeric level. The papers are conveniently divided into dynamic and structural studies, with some small overlap. 

In the area of polymer dynamics and relaxation, attention has concentrated on the significance of C relaxation times in the rotating frame (Ty,). C nuclear polarization in the rotating frame can decay either by spin-lattice relaxation or by 

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