PDPhSM

CP/MAS NMR spectrum of PDPhSM, shown in Fig. 14, is very complicated and contains some peaks which arise because the molecular motion of the phenyl rings of PDPhSM is restricted at room temperature. There are two signals at 0.0 and —3.1 ppm which are assigned to the main chain methylene group in a similar manner to the Si NMR result. Thus, there exists two conformational isomers in the crystalline region of PDPhSM. 

Molecular motion of the phenyl ring of PDPhSM and PMPhSM... 

Fig. 13. " Si CP/MAS (a) and - Si DD/MAS NMR (b) spectra of PDPhSM at room temperature. The signal corresponding to the non-crystalline region is indicated by an asterisk.

Structural characterization of PDPhSM and PMPhSM by Si variable temperature CP MAS NMR... 

Figure 17 shows the change of the Si chemical shift values of PDPhSM... 

Fig. 16. CP+DDph NMR spectra in the phenyl region of PMPhSM (a) at room temperature and PDPhSM at room temperature, (b) at 113°C, and (c) at 226 C.

Fig. 17. 2 Si CP/MAS NMR spectra of PDPhSM at various temperatures. Each spectrum was recorded for 56 scans and a repetition time of 20 s.

Fig. 18. The plots of chemical shifts and relative intensities for two signals of PDPhSM against temperature in a wide range of temperatures from 2TC to 226 C. (O low frequency peak, Q high frequency peak, intensity of low frequency peak and intensity of high frequency peak)...

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