Enhanced crystallinity, hardness and thermal stability of PEEK/TC4 composites for biomedical applications

Polyether-ether-ketone (PEEK) is widely recognized as a high-performance polymer for biomedical and structural applications, yet its limited hardness and moderate thermal resistance often restrict its use under demanding service conditions. This study presents the development of PEEK/Ti-6Al-4 V (TC4) composites processed via centrifugal powder compaction followed by vacuum sintering. Three compositions PT(20), PT(30), and PT(40), containing 20%, 30%, and 40% TC4 by weight were systematically investigated. Scanning electron microscopy (SEM) revealed homogeneous dispersion of TC4 particles in the PEEK matrix with localized interfacial bonding, as required for ensuring mechanical integrity during cyclic stressing conditions. Differential scanning calorimetry (DSC) showed that TC4 particles function as heterogeneous nucleating agents, which result in the enhancement of crystallinity from 41% in neat PEEK to 48% in the PT(40) composite, without significantly affecting the melting temperature. Moreover, X-ray Diffraction (XRD) supports DSC results in that metal fillers enhance the crystallization of polymer matrix. Thermogravimetric analysis (TGA) demonstrated improved thermal stability, with PT(40) composite retaining 75% weight at 800 °C compared to 53% of neat PEEK, which indicates suitability in temperature changing environments. Microhardness measurements indicated rising values with TC4 content, reaching a 35% improvement in PT(40). These findings demonstrate that the applied processing method enables property-tailored PEEK/TC4 composites suitable for thermally stable, mechanically robust structures demonstrating potential for demanding structural or biomedical applications.