Influence of Low TiO2 Nanoparticle Loading on Electrospun sPEEK Fiber Morphology and Chemistry and on the Tensile Properties of Corresponding Solution-Cast Membranes

Abstract

Polymer matrix composites (PMCs) have garnered importance due to their unique combination of mechanical, thermal, and functional properties. However, their performance depends on overcoming challenges related to dispersion, bonding, and processing. Electrospinning is an advanced technique for producing nanofiber or microfiber PMCs. One of the key challenges in electrospun PMCs is the uniform dispersion of reinforcement materials like TiO2 nanoparticles within the polymer matrix. A Taguchi orthogonal design (L16) was used to evaluate the effects of needle-to-collector distance, applied voltage, and flow rate on mean fiber diameter and deposition quality. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) were used to characterize electrospun neat sulfonated poly(ether ether ketone) (sPEEK) and sPEEK/TiO2 fibers, whereas tensile tests were performed on solution-cast membranes prepared from the corresponding formulations. The lowest observed run mean diameter was 204.6695 nm at 8 kV, 1.25 mL h−1, and a needle-to-collector distance of 12 cm; this run was also selected for deposition quality. Neat sPEEK membranes exhibited a mean tensile strength of 35.3 MPa, a mean apparent tensile modulus of 476 MPa, and a mean elongation at fracture of 18%. Among the TiO2-containing formulations, increasing the TiO2 content from 0.04 to 0.10 wt.% was associated with higher mean apparent tensile modulus and tensile strength and lower mean elongation at fracture. The 0.10 wt.% formulation exhibited the highest mean apparent tensile modulus and tensile strength.