Incorporation of <scp> MoO ₃ </scp> Nanoparticles Into Polypropylene Fibers via Melt Spinning: Investigation of Mechanical, Thermal, and Chromic Properties

ABSTRACT Polypropylene (PP) composite fibers containing 0.10, 0.20, and 0.50 wt% molybdenum oxide (MoO 3 ) nanoparticles were produced via melt spinning. In the present study, the effect of this addition on the mechanical, thermal, and chromic properties of the fibers was investigated. Scanning electron microscopy confirmed good dispersion of the nanofiller within the PP matrix at low concentrations (0.10 wt%) and the presence of agglomerates in samples containing higher amounts. Additionally, a modest nucleating effect associated with the filler was observed, with an increase in the degree of crystallinity of the fibers and an improvement in the limiting oxygen index in all samples compared to the control. On the other hand, molybdenum accelerated the initial decomposition of PP and decreased the melt viscosity, indicating possible polymer degradation in the filled materials. The mechanical properties were investigated, highlighting an approximately 8% increase in the tenacity of the yarn containing the lowest amount of the metal oxide and a considerable loss of tensile strength in the yarns with 0.20 and 0.50 wt%, attributed to poor filler dispersion. A thermochromic effect was observed in the PP/MoO 3 masterbatch containing 5.00 wt% of the nanofiller and in the fibers after the extrusion process, with a color change from white to blue in these materials.