title: Characterisation of the rheological properties and zeta potential of a range of hydroxyapatite powders.
abstract: The effect of precipitation temperature, i.e. particle morphology on the rheological properties of a hydroxyapatite (HA) slip was investigated and compared to a commercial HA (batch P120 supplied by Plasma Biotal, Tideswell, Derbyshire, UK). The commercial HA was highly crystalline and had a particle size much larger than the HA precipitated at 60 and 80 degrees C. With no deflocculant addition, the commercial HA had a viscosity much higher compared to the precipitated HA as expected. The commercial HA and the HA precipitated at 60 degrees C showed similar pseudoplastic behaviour, but the HA precipitated at 80 degrees C showed Newtonian behaviour. This was explained by the HA precipitated at 80 degrees C having mean particle size of 82.24 nm, but a much wider particle size distribution. This is confirmed by the electrophoretic mobility measurements which show that the HA precipitated at 80 degrees C has a much lower zeta potential at a 0 wt% addition of deflocculant. Because of the wider particle size distribution, the need to add deflocculant is much reduced.
authors.affiliation: Department of Biomaterials, Eastman Dental Institute, University College London, UK. j.knowles@eastman.ucl.ac.uk
authors.forename: J C
authors.initials: JC
authors.lastname: Knowles
authors.forename: S
authors.initials: S
authors.lastname: Callcut
authors.forename: G
authors.initials: G
authors.lastname: Georgiou
mesh_terms: D011232:Chemical Precipitation; D017886:Durapatite / Q000737:chemistry*; D004586:Electrophoresis; D008854:Microscopy, Electron; D010316:Particle Size; D011208:Powders; D012212:Rheology; D013696:Temperature; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D011208:Powders; D017886:Durapatite