Carbon fiber reinforced polyetheretherketone (CF/PEEK) is a high-performance thermoplastic composite material. Compared with traditional carbon fiber reinforced epoxy resin thermosetting composite materials, it has the characteristics of good high-temperature mechanical properties, good thermal stability, impact resistance, easy repair, easy storage and high molding efficiency. Therefore, CF/PEEK composite materials are widely used in the fields of aerospace, automobiles, medical treatment, petrochemicals, etc.

Recently, Professor Qi Zhenchao of Nanjing University of Aeronautics and Astronautics published a paper titled «The Effect of Temperature and Strain Rate on the Strengthening Behavior of Carbon Fiber Reinforced Polyetheretherketone (CF/PEEK) Composites under Shear Load», which systematically studied the effects of temperature and strain on the shear behavior of CF/PEEK composites and found that as the temperature increased from 20 ℃ to 130 ℃, the yield stress decreased by about 66%, and the rate of decrease was fast at first and then slowed down, as shown in Figure 1; as the strain rate increased from 10 ^-5 s ^-1 to 0.1s ^-1 , the yield stress increased by about 35% uniformly, as shown in Figure 2, which contributed to broadening the application range of CF/PEEK. Among them, the CF/PEEK composite materials they selected came from Jiangsu Junhua Special Engineering Plastics Products Co., Ltd.

In recent years, research on PEEK has mainly focused on medical devices. This is mainly because the elastic modulus of PEEK is about 3-4 GPa, which is closer to the elastic modulus of bone tissue (cancellous bone 3.2-7.8 GPa, cortical bone 17-20 GPa) compared to pure titanium (110 GPa). It can avoid the stress shielding effect, effectively transfer the stress of the bone tissue interface in a balanced manner, and maintain the stability of the bone-bonding interface. However, compared with metal implants, the mechanical properties of PEEK need to be improved, and fiber reinforcement is a very effective method. At present, there are glass fiber and carbon fiber reinforced PEEK composite materials. Taking CF/PEEK as an example, LU-CF/PEEK is prepared using CF/PEEK unidirectional prepreg 0°, and its longitudinal modulus can reach 130 GPa!

At present, the applications of PEEK and its reinforced materials in the medical industry include PEEK positioning frames used in orthopedic surgical robot surgical positioning, PEEK medical catheters, femoral intramedullary nail aiming frames, PEEK external fixation brackets, etc.

The figures and data in the article are from: Yao Chenxi, Qi Zhenchao, Chen Wenliang, et al. Effects of temperature and strain rate on the strengthening behavior of carbon fiber reinforced polyetheretherketone composites under shear loading[J]. Journal of Composite Materials, 2021, 38.