The Effect of Porosity on the Structure and Properties of Calcium Polyphosphate Bioceramics

Calcium polyphosphate (CPP) bioceramic with different porosities were prepared by controlling the concentration of the pore-foaming agent. Effect of porosity (0%, 15%, 30%, 45% and 60%) on the microstructure, pores interconnection, dissolution behavior and compressive strength of CPP bioceramic were investigated. Scanning electron microscope (SEM) and capillarity test results indicated that CPP with higher porosity (45% and 60%) exhibited three-dimensional interconnected pore structure with a pore size of about 200–400 μm, while the pores of lower porosity scaffold (0%, 15% and 30%) were isolated. The dissolution behavior in vitro indicated that the dissolution rate accelerated with the porosity increasing and the CPP with 60% porosity showed the highest dissolution velocity. The compressive strength of porosity CPP scaffolds were as much as the human cancellous bone, which decreased with the increase of porosity. While the dense CPP scaffolds lie in the same order of magnitude as compact bone.