Biomimetic nacre-like hydroxyapatite/polymer composites for load-bearing bone implants application
TABRIZIAN P. 1, SUN H. 1, JARGALSAIKHAN U. 2, SUI T. 2, DAVIS S. 1, SU B. 1
1 University of Bristol, Bristol, United Kingdom; 2 University of Surrey, Guildford, United Kingdom
Inspiration from natural materials helps us prepare a strong and tough composite with assembled brittle blocks into specific architectures. Hydroxyapatite (HA) as a main inorganic component of the bone and tooth, has high biocompatibility, but is weak and brittle. The main goal of this study is prepared biomimetic materials with a combination of high strength and toughness which potentially could be used as load-bearing bone implants. To achieve this, long-range aligned lamella HA scaffolds were prepared by bidirectional freeze-casting technique, which were further densified and infiltrated with polymer to produce nacre-like HA/polymer composites with high strength and toughness. The nacre-like HA/ (methyl methacrylate (MMA) + 5% acrylic acid (AA)) composites showed flexural strength of 158 MPa, Young's modulus of 24 GPa, and toughness of 3.2 MPa·m1/2. To improve the toughening behavior of composite further, HA nanowires and Apatite wollastonite (AW) were also introduced to the composite as reinforcement in the ceramic phase. The fracture behaviors and toughening mechanisms of the improved nacre-like HA/polymer composites are investigated and discussed.