Bi-directional regulatable mechanical properties of 3D braided Polyetheretherketone (PEEK)

Fabricating adjustable mechanical properties of biomaterials at different level remains an important challenge in obtaining suitable bone substitutes with stiffness at micro scale and toughness at macro level. In this study, the changes in structure and properties of three dimension braided polyetheretherketone (3D-braided PEEK) after hot-pressed at 345 degrees C, 355 degrees C and 365 degrees C were investigated. The hyperfield 3D microscopy images and DSC revealed more compact macrostructure and lower crystallinity of 3D braided PEEK at higher hot-pressing temperature. The depth-sensing indentation data exhibited a reduction in elastic modulus of 3D braided PEEK with increasing the hot-press temperature, but its strength and toughness measured via universal material experiment machine increased. These results suggested that the micro-mechanics properties of braided PEEK matrix can be adjusted by altering its intrinsic crystal structure that governed by the hot-pressing temperature, whereas its macro-mechanics characteristics by changing its macrostructure that depended on textile structure. Present findings made a breakthrough in simultaneously regulating the micro-and macro-mechanics properties of PEEK in an opposite manner, which should have promising application in the development of customized orthopedic implants.