Abstract In this work, high performance composite materials with high mechanical strength and isotropic properties are expected to obtained. Long carbon fiber (40 mm) reinforced poly(ether ether ketone) (PEEK) composites were prepared by three-dimensional (3D) needle-punched method. Orthogonal test was used to optimize molding parameters of 3D needle-punched CF/PEEK (30/70) composites. The influence of carbon fiber content and its orientation on the mechanical properties, thermal properties, crystallization properties and microstructure of the composites were studied in the range of 30-60 wt %. The excellent mechanical properties were shown with the increase of fiber content, and the composites were approximately isotropic in-plane due to the random fiber orientation. With the increase of carbon fiber content, the melting point measured by differential scanning calorimetry (DSC) and 5% weight loss temperature tested by thermogravimetric analysis (TGA) of the composites increased slightly, however the heat deflection temperature (HDT) increased obviously. SEM observation showed that compared with traditional thermoplastic plate, 3D needle-punched CF/PEEK composites could provide multi-direction impregnation channel for PEEK melt resin to realize multi-point impregnation, as a result, carbon fiber had a better impregnation effect in PEEK resin matrix. It was found that the tensile modulus and flexural modulus of CF/PEEK were very close to those of human cortical bone. It would reduce the stress shielding effect and has great application value if it is applied to the orthopaedic bone plate.

中文翻译：

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长碳纤维及其取向对三维针刺CF/PEEK复合材料性能的影响

摘要 在这项工作中，有望获得具有高机械强度和各向同性的高性能复合材料。通过三维 (3D) 针刺法制备长碳纤维 (40 mm) 增强聚醚醚酮 (PEEK) 复合材料。正交试验用于优化 3D 针刺 CF/PEEK (30/70) 复合材料的成型参数。研究了碳纤维含量及其取向对复合材料力学性能、热性能、结晶性能和微观结构的影响，范围为 30-60 wt%。随着纤维含量的增加，显示出优异的机械性能，并且由于随机纤维取向，复合材料在面内近似各向同性。随着碳纤维含量的增加，差示扫描量热法（DSC）测得的熔点和复合材料热重分析（TGA）测得的5%失重温度略有升高，但热变形温度（HDT）明显升高。SEM观察表明，与传统热塑性板材相比，3D针刺CF/PEEK复合材料可为PEEK熔体树脂提供多向浸渍通道，实现多点浸渍，因此碳纤维在PEEK树脂中的浸渍效果更好矩阵。发现CF/PEEK的拉伸模量和弯曲模量与人皮质骨非常接近。应用于骨科接骨板会降低应力屏蔽效果，具有很大的应用价值。