Improvement of the Mechanical Properties of Calcium Phosphate Bone Substitutes by Polycaprolactone Infiltration
In this study we show that mechanical properties of bioceramic scaffolds can be significantly improved by repeated infiltration with a low-viscosity polycaprolactone solution. Biphasic calcium phosphate (BCP: 70% hydroxyapatite, 30% β-tricalcium phosphate) scaffolds characterized by a bimodal pore size distribution and a global porosity of 70% have been chosen as starting materials. Polymer content in the ceramic scaffold was varied so that an inorganic/organic ratio close to that of bone may be achieved. Work of fracture at maximum stress was 36 J/m2 for the ceramic scaffold alone and reached 127 J/m2 for the 8-times infiltrated samples. These results are superior to the ones previously obtained with polycaprolactone infiltrated alumina due to higher micropore content. We show that during bending tests, polycaprolactone phase formed fibrils while the crack propagated. Crack bridging by polycaprolactone ensured the integrity of the composite once the ceramic scaffold was broken and directly involved in the composite toughening. Because of its composition, microstructure and mechanical behavior of this kind composite can be an interesting candidate for bone substitution.
Guy Daculsi and Pierre Layrolle
M. Quiquerez et al., "Improvement of the Mechanical Properties of Calcium Phosphate Bone Substitutes by Polycaprolactone Infiltration", Key Engineering Materials, Vols. 361-363, pp. 403-406, 2008