Enhancing durability: An investigation into the wear mechanisms in hybrid poly-ether-ether ketone (PEEK) nanocomposites with glass fiber and HAp nanoparticle additives

Semi-crystalline poly-ether-ether ketone (PEEK) is recognized for its superior strength, biocompatibility and high-temperature resistance, surpassing many other polymers. However, its application in bioimplants is limited by poor osteoconductivity, suboptimal wear resistance and lower mechanical strength compared to natural bones. To unlock the full potential of PEEK in biomedical applications, it is crucial to develop PEEK-based composites that can overcome these limitations. This study addresses these challenges by creating a hybrid PEEK-based nanocomposite reinforced with varying volume fractions of short glass fibers (GF), hydroxyapatite (HAp) nanoparticles and their combination. The focus is on evaluating their mechanical and tribological properties. Structural analysis demonstrates that a uniform dispersion of the reinforcements within the PEEK matrix significantly enhances mechanical properties, including microhardness, elastic modulus, and compressive strength. Specifically, compared to pure PEEK, the hybrid PEEK nanocomposites containing 5 vol% GF and 5 vol % HAp nanoparticles exhibits notable improvements, with a 33.7 % increase in microhardness, a 30.95 % enhancement in elastic modulus, and a 42.8 % boost in compressive strength. These enhanced properties bring the mechanical characteristics of the nanocomposites closer to those of human cortical bones. Additionally, micro-scratch and ball-on-disk wear tests reveal that while the inclusion of hybrid particulates does not significantly alter the coefficient of friction, leading to a marked improvement in wear resistance, with minimal subsurface damage. These findings highlight the potential of hybrid PEEK nanocomposites for utilizing in load bearing implants, offering a promising path forward in the development of biomedical materials with enhanced bio-and mechano-compatibility.