title: Wet or dry mechanochemical synthesis of calcium phosphates? Influence of the water content on DCPD-CaO reaction kinetics.
abstract: Mechanosynthesis of calcium phosphates can be performed under wet or dry conditions. In most papers and patents, grinding under wet conditions was selected. So far, only a few papers were devoted to dry mechanosynthesis of calcium phosphates. To understand why wet mechanosynthesis was preferred, the influence of water addition on the kinetics of the mechanochemical reaction of dicalcium phosphate dihydrate with calcium oxide was investigated. The DCPD disappearance rate constant k and the final reaction time t(f) were determined in each case and correlated with the water content present in the slurry. Results showed that the addition water (i) slowed down the reaction rate and (ii) increased the powder contamination by mill material (hard porcelain) due to ball and vial erosion; and that (iii) wet milling did not generate the expected products, in contrast to dry grinding, because porcelain induced hydroxyapatite decomposition with the formation of beta-tricalcium phosphate and silicon-stabilized tricalcium phosphate. Consequently, dry mechanosynthesis appears preferable to wet milling in the preparation of calcium phosphates of biological interest.
authors.affiliation: Institut des Biomolécules Max Mousseron, Dpt Biopolymères Artificiels, IBMM UMR-CNRS 5247, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14 491, 34093 Montpellier Cedex 5, France.
authors.forename: H
authors.initials: H
authors.lastname: El Briak-Benabdeslam
authors.forename: M P
authors.initials: MP
authors.lastname: Ginebra
authors.forename: M
authors.initials: M
authors.lastname: Vert
authors.forename: P
authors.initials: P
authors.lastname: Boudeville
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis*; D001696:Biomechanical Phenomena; D017610:Calcium Compounds / Q000737:chemistry; D002130:Calcium Phosphates / Q000138:chemical synthesis* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D007700:Kinetics; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry; D033362:Powder Diffraction; D014867:Water