Effect of Slurry Preparation on Physical Properties of Porous Hydroxyapatite Prepared via Polymeric Sponge Method

Abstract

Hydroxyapatite porous materials for cancellous bone applications were prepared via polymeric sponge method. Suspensions of the nanostructured hydroxyapatite powders were prepared via stirring of the mixture of hydroxyapatite powder, water, and dispersing agent. The stirring time was adjusted at 4 and 20 hours. After soaking cellulosic sponges into the suspension, the sponges were dried and then subjected to heat-treatment at 600°C, followed by sintering at 1250°C for 1 h. No additional phases were identified in the sintered porous hydroxyapatite. This result showed that the sintering process did not alter the hydroxyapatite phase composition. The study found that the apparent density of the porous bodies varied from 1.69 g/cm3 to 2.03 g/cm3 with 35.6 – 46.2 % porosities and 100-500 microns macropore size depending on the composition of slurry and the stirring time. Longer stirring time resulted in the breakdown of HA agglomerates and the slurry obtained tends to be more homogeneous, leading to higher density and better compressive strength of the sintered porous bodies. The measurement of compressive strength provided the values of 4.3 MPa and 10 MPa for 4 h and 20 h stirring time, which is in the range of mechanical strength of human cancellous bone.