Polypropylene/Poly(vinyl alcohol) Blends Compatibilized with Kaolinite Janus Hybrid Particles and Their Transformation into Fibers

This study focuses on the adoption of hybrid Janus kaolinite particles into immiscible PP-PVA blends for melt spinning, as an extension for the textile field. The anisotropic grafting of kaolinite by octadecylphosphonic acid allowed the localization of the particles at the PP-PVA interface. Then surface-modified PP porous fibers have been obtained by selective extraction of the PVA phase. The SEM observations and selective extraction experiments indicated that the unmodified kaolinite particles were localized within the PVA phase having limited impact on the PVA accessibility, while Janus-modified particles were distributed at the biphasic interface decreasing significantly the PVA accessibility. The volume average diameter of PVA within annealed blends is dramatically decreased from 73.3 to 13.6 mu m by the addition of 5 wt % of Janus kaolinite particles, proving the strong compatibility effect. Gel-like behavior was also observed in rheological investigations for blends filled with modified kaolinite. The melt flow index (MFI) was tested for adapting the conditions of melt spinning. The PVA accessibility can reach more than 90%, and the interface-located fillers can enhance the Young's modulus of the biphasic fibers with 57% increment. The crystallization structure of the porous PP fibers was also influenced by the Janus kaolinite particles, with the enhancement of crystal perfection.