Thermal Change of Magnesium Highpolyphosphate Coacervates

Abstract The thermal change of magnesium highpolyphosphate coacervates with various sodium contents was studied by means of DTA, TGA and high temperature X-ray diffraction technique. Most of the highpolyphosphates in the coacervates were degraded into hydrated orthophosphates up to about 100 °C, the pyrophosphates and tetrametaphosphates being formed at 200–300 °C and 300–500 °C, respectively. The formation temperature of “X” (a mixture of Mg2P2O7 and MgNa2P4O12) was lowered with an increase of sodium content in the coacervate samples. Mg(H2PO4)2·2H2O, Mg(H2PO4)2, MgH2P2O7, “X” and Mg2P4O12 were determined in the crystalline substances obtained by the isothermal heat treatment of coacervates at various temperatures.