Infrared Absorption Spectra of Alternating Copolymers of Butadiene with Acrylonitrile and Deuterated Analogues

Polarized IR spectra of alternating copolymers and random ones of butadiene with acrylonitrile have been investigated in the region from 4000 to 250 cm−1. The spectra of deuterated alternating copolymers have also been measured. It has been found that dichroism appears to a marked extent when films of the alternating copolymer are elongated, whereas it is hardly observable for the random one. The results were discussed from a viewpoint of orientation of polymer molecules and crystallites in the films of alternating copolymer. Tentative assignments of the absorption bands were made with reference to the results for trans-1,4-polybutadiene and those for polyacrylonitrile. The molecular structure of the alternating copolymer is discussed.