Effect of Polymerization Temperature on Polymerization Degree and Structure of Calcium Polyphosphate

The properties of calcium polyphosphate (CPP) were greatly affected by its polymerization degree. A se- ries of CPP with different polymerization degree were prepared by polymerization of calcium phosphate monobasic monohydrate (MCP) at different temperatures. Polymerization degree was analyzed by liquid state 31 P nuclear mag- netic resonance ( 31 P-NMR). The effect of different temperature on polymerization degree and structure of CPP was discussed. MCP was analyzed by differential scanning calorimetry-thermmogravimetry (DSC-TGA) and possible mechanism of the polymerization reaction was proposed. The results show that polymerization of MCP mainly pro- duces CPP. When the elevation temperature is below 1000℃, polymerization degree increases; however the opposite is true when the polymerization temperature exceeds 1000℃. Additionally, the formation of a ring-structure phos- phate, namely calcium metaphosphate (CMP), is also promoted with increasing polymerization temperature. The CMP content increases with increasing polymerization temperature and significantly increases when the polymeri- zation temperature is above 1000℃.