ANALYSIS OF THE KINETICS OF DISSOLUTION AND THE EVOLUTION OF THE MECHANICAL PROPERTIES OF A PHOSPHATE GLASS STORED IN SIMULATED BODY FLUID

Phosphate glasses are of a great interest for bone substitution materials, due to their chemistry close to that of the inorganic phase of bone and their unique property of being completely soluble. The aim of this study is to evaluate the kinetics of dissolution and the evolution of the mechanical properties of a phosphate glass in the system P₂O₅-CaO-Na₂O when kept in simulated body fluid (SBF). The results showed that the dissolution presented two different stages. In the first stage, the glass showed a mass loss varying at a rate proportional to t^0.55 and, after a certain time, the kinetics turn to linear dissolution. The mechanical properties during the dissolution of the glass showed values of E between 48 and 57 GPa and σ_f between 130 and 167 MPa. The glass showed no significant decrease of its mechanical properties after 8 weeks in SBF. The properties obtained are really promising for the use of phosphate glasses as a bone substitute in certain surgical applications.