Microscopic investigation of the optical and morphological properties of iPP/TiO2 nanocomposite fibres using computed tomography technique.

In this article, the optical and structural properties of iPP/TiO2 nanocomposite fibres, considering three distinct extrusion speeds (25, 50 and 78 m/min) in addition to blank isotactic polypropylene samples were determined. Employing computed tomographic scans, localised optical defects in the nanocomposite fibres are unveiled, while refractive indices are examined by analysing transmitted intensity with incident light vibrating parallel and perpendicular to the fibre axis. The internal structure is further characterised through birefringence and density calculations. Mechanical properties, specifically stiffness, are probed by measuring elastic modulus values along the fibre. The investigation extends to the presence of TiO2 nanoparticles in the isotactic polypropylene matrix, inspecting their influence on the uniform morphology along and across the fibre. While the addition of TiO2 nanoparticles has many advantages, including enhanced properties, the study shows adverse effects on the morphological integrity of the fibres, particularly at higher extrusion rates. Micrographs are included to visually illustrate these findings, providing a comprehensive understanding of the complex interaction between extrusion rates, TiO2 nanoparticle incorporation, and the resulting optical and structural properties in iPP fibres. LAY DESCRIPTION: Computed tomographic scans of iPP/TiO2 nanocomposite fibers were used to investigate their optical and structural properties. Three samples of the nanocomposite fibers were extruded with extrusion speeds (25 m/min, 50 m/min, and 78 m/min) in addition to blank isotactic polypropylene sample were used in this study. Employing computed tomographic scans, localized optical defects in the nanocomposite fibers are unveiled, while refractive indices are examined by analyzing transmitted intensity with incident light vibrating parallel and perpendicular to the fiber axis. The internal structure on the molecular level was characterized through birefringence and density measurements. The effect of the extrusion speed on the structure of iPP/TiO2 nanocomposite samples was investigated through measuring their birefringence and density distributions along the fiber axis. The mechanical properties, specifically stiffness, are probed by measuring elastic modulus values along the fiber axis. The investigation extends to the presence of TiO2 nanoparticles in the isotactic polypropylene matrix, inspecting their influence on the uniform morphology along and across the fiber. Slow extrusion rates enhance the properties of iPP fiber, while fast extrusion introduces agglomerated sites which has drastic effect on the optical and structural properties of TiO2‐doped iPP fibers. Micrographs are included to visually illustrate these findings, providing a comprehensive understanding of the complex interaction between extrusion speed, TiO2 nanoparticle incorporation, and the resulting optical and structural properties in iPP fibers. [ABSTRACT FROM AUTHOR]