Molecular Modelling of the Structure of Polyacrylonitrile Fibres

In spite of considerable effort, attempts to explain the physical structure of fibres based on atactic polyacrylonitrile have so far met only with limited success. This paper shows that molecular modelling, used in conjunction with X-ray diffraction, provides an essential additional input for explaining the nature of the ‘ordered regions’ in these fibres. It is suggested that these ordered regions, consisting of regularly assembled irregular helices, should be viewed as ‘configurationally disordered crystals’.