Polystyrene dipolar sideband patterns

Figure 3. Experimental dipolar sideband patterns for the protonated aromatic carbon of polystyrene (left) and of crystalline dimethoxybenzene (right) under magic-angle spinning at 1.894 kHz.

The amplitudes of ring- and main-chain motions of a variety of polystyrenes have been established from the 13C NMR magic-angle spinning sideband patterns of dipolar and chemical shift tensors. The frequencies of the same motions have been determined by TiCC) and TjpCC) experiments. The most prevalent motion in these polymers is restricted phenyl rotation with an average total displacement of about 40°. Both the amplitude and frequency of this motion vary from one substituted polystyrene to another, and from site to site within the same polystyrene. A simple theory correlates the observed ring dipolar patterns with s. 

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