Thermal stability of brushite with chitosan samples

Abstract

In this paper, the powders of brushite from an aqueous solution of Ca(NO[3])[2]- (NH[4])[2]HPO[4] with different content of chitosan were synthesized. XRD data revealed that all samples are single-phase and are brushite (CaHPO[4]•centerdot2H[2]O). By FT-IR spectroscopy and BET methods, it was found that chitosan adsorbs onto the surface of powders. With increase of the content of the additive, the average size of crystallites increases 4.0 – 4.8 – 11.8 [mu]m, respectively, and the dissolution rate in isotonic solution also decreases. The thermal stability of the composite powders was studied. It was established that the highest destruction of samples occurs in the range 473-673 K by removing of adsorption and crystallization water and partial change of the structure of the mineral and chitosan. At a temperature of 873 K, carbonization of the organic additive occurs.