EFFECT OF WATER-SOLUBLE ORGANIC POLYMER ON HARDENING OF CALCIUM PHOSPHATE CEMENT

A hard body of calcium phosphate cement was prepared by mixing α-type tricalcium phosphate or tetracalcium phosphate and a polyacrylic acid solution and then hardening the paste. Mechanical strength of the hard body increased with increasing concentration of polyacrylic acid and pH value of the solution. Hardening time to cure the paste decreased with increasing concentration of polyacrylic acid and increased with increasing pH value of a polyacrylic acid solution. The calcium phosphate cement of α -type tricalcium phosphate gave stronger mechanical strength than that of tetracalcium phosphate. The highest compressive strength of 67.3 and 47.1 MPa were given for the hardened cements of α -type tricalcium phosphate and tetracalcium phosphate, respectively. Mechanical strength of the cement increased with the passage of time at the first step and then decreased after one month.