Kang Jianfeng, Zheng Jibao, Hui Yijun, Li Dichen
Jihua Laboratory, Additive Manufacturing Institute, Foshan 528200, China.
State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710032, China.
Polymers (Basel). 2022 Oct 12;14(20):4293. doi: 10.3390/polym14204293.
The incorporation of bioactive ceramic into polyether ether ketone (PEEK) was expected to improve the bioinertia and hydrophobicity of pure PEEK, further facilitating osseointegration and bone ingrowth. However, the addition of bioceramic also changes the anisotropy of mechanical properties and failure mechanism of composite. Therefore, three-dimensional printed (3D-printed) PEEK/hydroxyapatite (HA) composite filaments with differing proportions (HA content: 10-30 wt%) were prepared using physical mixture and melting extrusion processes. The tensile elastic modulus and tensile strength of composite filaments were tested experimentally. These microscopic models, with multiple diameter variations and differing dispersity of HA particles, were built to estimate mechanical properties using finite element analysis. Based on a generalized version of Hooke's Law, the influence of diameter variation and particle clustering on the elastic modulus was evaluated. The mathematical relationship between the elastic modulus and volume fraction of the bioceramic was established using the Halpin-Tsai model. The results showed that with an increase in HA content from 10 wt% to 30 wt%, the elastic modulus of the composite increased from 2.36 GPa to 2.79 GPa, tensile strength decreased from 95 MPa to 74 MPa, and fracture elongation decreased from 63% to 23%, presenting brittle fracture failure. When the dispersion of particles was uniform, the elastic modulus was less affected by diameter variation, but the modulus anisotropic coefficient was greatly affected by the composition ratio, particle diameter, and dispersity. Hence, 3D-printed PEEK/HA composite filaments can meet the strength requirements of human bone, and understanding the influence of mechanical anisotropy plays a very important role in the design, manufacture, and clinical application of medical implants.
将生物活性陶瓷掺入聚醚醚酮（PEEK）有望改善纯PEEK的生物惰性和疏水性，进一步促进骨整合和骨长入。然而，生物陶瓷的添加也改变了复合材料力学性能的各向异性和失效机制。因此，采用物理混合和熔融挤出工艺制备了不同比例（HA含量：10 - 30 wt%）的三维打印（3D打印）PEEK/羟基磷灰石（HA）复合长丝。对复合长丝的拉伸弹性模量和拉伸强度进行了实验测试。构建了这些具有多种直径变化和不同HA颗粒分散度的微观模型，以使用有限元分析来估计力学性能。基于胡克定律的广义形式，评估了直径变化和颗粒团聚对弹性模量的影响。使用Halpin-Tsai模型建立了生物陶瓷弹性模量与体积分数之间的数学关系。结果表明，随着HA含量从10 wt%增加到30 wt%，复合材料的弹性模量从2.36 GPa增加到2.79 GPa，拉伸强度从95 MPa降低到74 MPa，断裂伸长率从63%降低到23%，呈现脆性断裂失效。当颗粒分散均匀时，弹性模量受直径变化的影响较小，但模量各向异性系数受组成比、粒径和分散度的影响较大。因此，3D打印的PEEK/HA复合长丝能够满足人体骨骼的强度要求，了解力学各向异性的影响在医疗植入物的设计、制造和临床应用中起着非常重要的作用。
