Utilising cold sintering process for sintering hydroxyapatite-polyetheretherketone nanocomposite

Purpose: A novel technique of very low-temperature sintering named the cold sintering process is used to produce Highly dense hydroxyapatite-polyetheretherketone (HA-PEEK) nanocomposites. The polymers and ceramics are sintered at different temperatures; therefore, it is difficult to create ceramic matrix composites using traditional methods because the high temperatures might damage the polymers. It is hard to concurrently treat polymeric materials at high temperatures because HA often sinters at temperatures exceeding 1000°C. So, the study aimed to use a novel low-temperature sintering named Cold Sintering Process (CSP) with a Ts/ Tm ratio greater than 0.2 to alleviate this issue. This method could offer a production path with quick densification and less energy costs to increase throughput. Design/methodology/approach: In the current work, two different routes are used: The direct mixing and dissolution methods were used for powder preparation to fabricate a unique ceramic matrix composite. The study aimed to determine whether the preparation method could produce two continuous phases for better densification. The sintering temperature, pressure, holding time, and PEEK content were selected as the production parameters. The samples are characterised using a scanning electron microscope (SEM), X-ray energy dispersive spectrometry (EDS), an X-ray diffractogram (XRD), and a transition electron microscope (TEM). Also, physical and mechanical property measurements were detected, including density, water contact angle, hardness, and diametral tensile strength (DTS). Findings: It can be observed that a high densification compact (relative density 99.3%) can be observed by using the dissolution method HA-PEEK composites, which can be produced via the cold sintering process. The dissolution method can produce two continuous phases compared with the direct mixing method. All samples exhibit excellent hydrophilicity, which makes them good candidates for biomedical applications. Research limitations/implications: The biggest implication of the cold sintering method is the difficulty of making large-sized and complex-shaped samples. Practical implications: The dissolution method can produce two continuous phases compared with the direct mixing method. All samples exhibit excellent hydrophilicity, which makes them good candidates for biomedical applications. Originality/value: A novel technique was used for the first time to solve the problem of producing ceramic matrix composites with polymer as the dispersion phase.