NMR and X-ray diffraction study of the polyacrylonitrile crystallites

An attempt was made to establish the correlation between the tacticity of the molecular chain of polyacrylonitrile (PAN) obtained with different types of initiating systems and the crystallite dimensions. X-ray and NMR spectroscopic studies showed that the lateral dimensions of the crystallites are controlled mainly by the temperature of polymerization (and crystallization, respectively), whereas the longitudinal dimensions along the molecular chain are controlled by the polymer microtacticity.