SOLVENT CASTING EFFECT ON THE INFRARED CHARACTERISTIC ABSORPTION-BANDS (1230 1250 CM(-1)) OF STEREOREGULAR ISOTACTIC POLY(ACRYLONITRILE) FILM/

The solvent casting effect on the infrared (IR) characteristic absorpt ion bands of stereoregular isotactic poly(acrylonitrile) (PAN) film wa s studied in comparison with those of an atactic sample. The relative intensity of the IR characteristic bands (D-1230/D-1250) Of PAN film w as strongly dependent on the kind of dipolar aprotic solvent used in t he film preparation. A higher intensity ratio was obtained when a good solvent such as dimethyl sulfoxide was used, whereas a lower value wa s obtained when a poor solvent such as malononitrile was used. A linea r relationship between the intensity ratio of the IR bands and the dis solution power of nine different kinds of dipolar organic solvents was found. The IR characteristic bands of stereoregular PAN was dependent on not only configuration but also conformation through the differenc e of the molecular cohesion state in the solvent-cast film. The effect ; of configuration and conformation on the IR results was quantitative ly studied as a function of the film preparation conditions.