SAXS investigations of isotactic polypropylene (IPP) fibres mass coloured with organic pigments

The effect of selected organic pigments on the supermolecular structure of isotactic polypropylene (IPP) fibre has been investigated. For the present work, three organic pigments of different molecular and supermolecular constitution were selected. Undrawn fibres with a minimal technological degree of drawing and fibres at draw ratios of 2, 4 and 5 were examined. The supermolecular structure was explored using small-angle X-ray scattering (SAXS). From the SAXS patterns the one-dimensional intensity function and the correlation function were determined. The parameters characterizing the supermolecular structure of the fibre, i.e. long period and invariant, were assessed. It was found that a lamellar structure develops during fibre formation. A regular lamellar structure is formed irrespective of the presence of pigments. On drawing fibres the high regularity of the lamellar structure decreases. In the drawing process the pigments are at the origin of micropore formation.