INFLUENCES OF REACTION TEMPERATURE AND TI ME ON HYDROLYSIS OF ALPHA-TRICALCIUM BIS(PHOSPHATE) IN SOLUBILIZED COLLAGEN SOLUTION

In order to examine the influences of the reaction temperature and tim e on the hydrolysis of alpha-tricalcium bis(phosphate) (alpha-TCP) in solubilized collagen solutions of pH 5, chemical analysis of the solut ions after the reaction, and X-ray diffraction, Fourier transform infr a-red spectroscopy, thermal analysis and chemical analysis of the hydr olyzed products were carried out. Calcium hydrogenphosphate dihydrate (DCPD) was at first formed and then hydroxyapatite (HAp) and octacalci um dihydrogenhexakis (phosphate) (OCP) were formed at 20-30 degrees C. However, the formation of DCPD was not detected at 35-40 degrees C. T he rates of formation for HAp and OCP increased with the increase of t he reaction temperature, and the presence of collagen accelerated the formation to them. The content of collagen increased with the increase of reaction temperature and time. Ca/P molar ratios of the hydrolyzed products varied ca. 1.3 to 1.5, because DCPD was formed in early peri od of hydrolysis and the formed HAp was nonstoichiometric hydroxyapati te in addition to the formation of OCP. Further, it was suggested from the results of investigation for chemical kinetics that alpha-TCP is hydrolyzed to HAp more easily by the presence of collagen.