Conformation effect and FT-IR diffuse reflection spectroscopy of stereoregular isotactic poly(acrylonitrile) prepared by urea clathrate polymerization

The conformation effect on the infrared intensity of the characteristic ban ds (1230/1250 cm(-1)) of stereoregular isotactic poly(acrylonitrile) (PAN) was studied by the diffuse reflection (DR) and KBr disk methods. The DR spe ctroscopic features of isotactic PAN were briefly discussed. The intensity ratios (D-1230/D-1250) Of the IR bands in the original sample (A) and the d issolution-recovered sample (B) were compared: the intensity of the latter sample decreased more than that of the former, the extent of which was larg er when the stereoregularity of the sample was higher. Little difference wa s observed in atactic PAN. These intensity variations were summarized as a function of the isotacticity of PAN, fr om which the effect of both conform ation and configuration was quantitatively evaluated. The intensity differe nce between the DR and KBr disk re suits was also reasonably explained in t erms of conformation. The IR behavior of other bands (1100 and 540 cm(-1) r egion) was briefly noted.