Characterization of magnesium phosphate cement fabricated using pre-reacted magnesium oxide

Magnesium phosphate cement (MPC) has the potential to be used as biomaterials but the high level of heat being generated during this exothermic reaction limits its use. It is very important to control the curing behavior of MPC. MPC was fabricated using pre-reacted magnesium oxide as raw materials in this paper. Pre-reacted magnesium oxide was fabricated according to the hydrated reaction mechanism of MPC. Curing behavior, phase compositions and microstructure of MPC were characterized, as well as the chemical activity of pre-reacted magnesium oxide. The results indicated that pre-reacted magnesium oxide was composed of residual magnesium oxide and hydrated products. The mean particles size increased as the hydrated products united magnesium oxide together to form bigger clusters; meanwhile the chemical activity decreased. The setting time and peak temperature of MPC was adjusted successfully, and the phase compositions are still same with those of MPC obtained by pure magnesium oxide. The phase compositions of MPC fabricated with different pre-reacted magnesium oxide particles were all composed of hydrated products and residual magnesium oxide. No observable impurity ensures the purity of MPC. The whole synthesis process of MPC in this work is composed of two stages. The first stage is to obtain pre-reacted magnesium oxide, and the second is to fabricate MPC using magnesium oxide obtained in the first stage. Both stages are designed according to the hydrated reaction mechanism of MPC, and thus ensure the purity of MPC. In conclusion, the curing behavior was successfully controlled, producing a same phase compositions to that of the MPC whilst causing the changes in the setting time and peak temperature.