Biomimetic apatite-based composite materials obtained by spark plasma sintering (SPS): physicochemical and mechanical characterizations

摘要

Nanocrystalline calcium phosphate apatites are biomimetic compounds analogous to bone mineral and are at the origin of the bioactivity of most biomaterials used as bone substitutes. Their unique surface reactivity originatesudfrom the presence of a hydrated layer containing labile ionsud(mostly divalent ones). So the setup of 3D biocompatibleudapatite-based bioceramics exhibiting a high reactivityudrequests the development of «low» temperature consolidationudprocesses such as spark plasma sintering (SPS), in order to preserve the characteristics of the hydrated nanocrystals. However, mechanical performances may still need to be improved for such nanocrystalline apatite bioceramics,udespecially in view of load-bearing applications. The reinforcement by association with biopolymers representsudan appealing approach, while preserving the advantageousudbiological properties of biomimetic apatites. Herein, we report the preparation of composites based on biomimetic apatite associated with various quantities of microcrystalline cellulose (MCC, 1–20 wt%), a naturaludfibrous polymer. The SPS-consolidated composites wereudanalyzed from both physicochemical (X-ray diffraction,Fourier transform infrared, solid state NMR) andudmechanical (Brazilian test) viewpoints. The preservation ofudthe physicochemical characteristics of apatite and celluloseudin the final material was observed. Mechanical propertiesudof the composite materials were found to be directly relatedudto the polymer/apatite ratios and a maximum crushingudstrength was reached for 10 wt% of MCC.