Study on the Nanomechanical and Nanotribological Behaviors of PEEK and CFRPEEK for Biomedical Applications

Jian Song,Zhongxiao Peng,Weiqiang Liu,Hongyu Shi,Yuhong Liu,Zhenhua Liao,Song Wang

doi:10.3390/polym10020142

Jian Song, Zhongxiao Peng + Show 5 more

Open Access

https://doi.org/10.3390/polym10020142

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Abstract

This study was to investigate the nanomechanical and nanotribological properties of polyether ether ketone (PEEK)-based composites for biomedical applications and to gain a fundamental understanding of the effects of carbon fibers in carbon-fiber-reinforced PEEK (CFRPEEK) on the mechanical properties and wear performance in a microscale. Nanoindentation tests with a Berkovich indenter and nanoscratch experiments with a diamond stylus were performed on PEEK and CFRPEEK samples. The nanowear features and mechanisms of the tested samples were analyzed using 3D white-light interfering profilometry and scanning electron microscopy (SEM). The obtained results indicated that the reinforced carbon fibers increased the nanohardness and elastic modulus and decreased the friction coefficient and wear rate of PEEK. Different to many existing studies where a constant load was used in a nanoscratch test and the normal load was a key factor influencing the scratch performances of the tested specimens, stick–slip phenomena were observed on both PEEK and CFRPEEK in the nanoscratch tests with load increasing progressively. In constant load conditions, it was found that the major nanowear mechanisms of PEEK are adhesion, abrasion, and plastic deformation, while the nanowear mechanisms of CFRPEEK are dominated by severe adhesive wear, abrasive wear and mild fatigue. CFRPEEK has demonstrated superior nanomechanical and nanotribological performances, and hence can be considered a potential candidate for biomedical applications.

Highlights

Over the past decades, polyether ether ketone (PEEK) has emerged as a leading high-performance thermoplastic candidate for replacing metal materials in the field of biomedical applications owing to its optimum radiation permeability, biocompatibility, and other advantages [1,2]
The obtained results in this study suggest that the nanotribological performances of carbon-fiber-reinforced PEEK (CFRPEEK)
The induced carbon fibers in PEEK matrix increased the nanohardness and reduced elastic modulus, which have a beneficial effect on the nanotribological performances of PEEK

Summary

Introduction

Polyether ether ketone (PEEK) has emerged as a leading high-performance thermoplastic candidate for replacing metal materials in the field of biomedical applications owing to its optimum radiation permeability, biocompatibility, and other advantages [1,2]. Existing modifications of PEEK, such as using PEEK as a base polymer matrix in combination with some biocompatible particles [4] or fibers [5], enhance its wear performances. New developments in carbon-fiber-reinforced PEEK (CFRPEEK) have made it an attractive. Polymers 2018, 10, 142 candidate in biomedical applications because it is reported that carbon fibers can further strengthen the mechanical and wear properties [6]. The conventional tribological properties of PEEK and CFREEK in biomedical applications have been investigated and documented. Xiong et al [8]

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