Formation and properties of polypropylene/stearic acid composite fibers

Abstract

This paper refers to the formation and properties of polypropylene/stearic acid (PP/SA) composite fibers. For the investigation, commercial metallocene-catalyzed PP polymer and SA were used. The fibers were produced in laboratory conditions using the single screw spin draw device. The textile-mechanical properties, surface composition, morphology and supermolecular structure of as-spun fibers were studied. Moreover, the nonisothermal crystallization of the PP/SA blend and melting behavior of fibers were analyzed. In the investigation Fourier transform infrared–attenuated total reflectance, scanning electron microscopy, differential scanning calorimetry and wide-angle X-ray analytical methods were used. The research showed that the PP/SA blend has lower viscosity compared to the pure polymer and that during the PP crystallization phase, separation is induced. SA delays crystallization of PP, and interaction between SA and PP is observed. The as-spun PP/SA fibers have higher linear density, higher elongation at break and slightly lower tenacity compared to fibers produced from pure PP. The fibers contain a structure with high content of mesophase. During fiber formation, SA migrates towards the fiber surface and forms droplets located beneath the surface of the fiber or crystallizes outside in the form of flake-like crystals.