Mechanical Properties of a composite material made of HAp nanofibers

J.R. Alanis, R. Velazquez, E.M. Rivera
Universidad Autónoma de Queretaro,

Keywords: hydroxyapatite


Biomaterials based on hydroxyapatite (HAp) are often studied due to the favorable answer presented as a substitute of bone tissue. However, the mechanical properties of these materials have not been studied deep enough. Synthesis of HAp nanofibers were done using Ca(NO3)2, K2(HPO4) and KOH as precursors and glutamic acid to guide the crystal growth. Nanofibers presented a high crystalline quality, preferential crystalline orientation in the [300] and they grew along [001]. Small porous ceramic pieces were made of HAp nanofibers through the modified gelcasting process and a controlled hierarchical porosity was obtained which is useful for its application as a bone tissue substitute. Then, an organic phase was added by impregnation to the ceramic. Structural studies were performed using X-Ray diffraction, morphology and microstructure were analyzed by scanning electron microscopy and high resolution electron microscopy. In addition, compression tests were made to this composite materials. A composite material made of HAp particles was also obtained and used as a reference for the mechanical characterization. This reference was synthesized using the same synthesis conditions and composition used for those material made of HAp nanofibers. The material made of HAp nanofibers showed a remarkable better mechanical resistance under compression compared to that found for the reference one. This mechanical resistance was similar to that observed in the trabecular bone. This mechanical resistance is the result of a synergic contribution from both components in the composite material, specially, from the nanofibers which have high resistance due to their crystalline orientation, dimensions and morphology.