Majda Sfiligoj Smole, Diana Gregor-Svetec*
University of Maribor, Textile Department, Smetanova 17, SI 2000 Maribor, Slovenia;
*University of Ljubljana, Department of Textiles, Snežniška 5, SI 1000 Ljubljana, Slovenia

Received 20-03-2002

The morphology of fibres consists of crystalline and noncrystalline domains forming the microfibrillar structure. Microvoids are present in form of inter- and intrafibrillar free spaces. In the presentation the microvoid system of poly(ethylene terephthalate) (PET) and poly(propylene) (PP) fibres was studied by small-angle x-ray scattering (SAXS). Commercial PET textile fibres were treated in different media and the influence on fibre homogeneity was followed by SAXS. Conventional water dyeing and hot air treatment of PET fibres have caused considerable changes in the microvoid system. The influence of these two treatment media on the structure of inner surface is very alike and even higher than the influence of supercritical fluids at the same temperature.
PP technical fibres were manufactured on a laboratory spin-drawing device and subsequently drawn at different drawing conditions on a laboratory drawing device. The  drawing has influenced the microvoid system of fibres, with drawing the size and volume fraction of voids have increased, resulting in spinodal change of the microvoid system.