Abstract
Thermal properties of the products formed by the hydrolysis of α-tricalcium bis (phosphate) (α-TCP) in solubilized collagen solutions were compared with those of hydrolyzed products without collagen, solubilized coll: ens, a commercially available hydroxyapatite (HAp) and a bovine tooth. The water of crystallization in c alcium hydrogenphosphate dihydrate formed at pH 4 wa s dehydrated in t wo steps (at ca.150 "C a nd ca.2 00°C). T here was no d ifference in t he total weight losses ( TG) of the hydrolyzed products through dehydration, but the ratio of the weight loss at ca.150°C t o that at ca.2 00°C w as different by the presence of collagen. The two peak temperatures (DTA) due to dehydrati on were varied owing to collagen.
The weight loss in T G (the amount of absorbed water and that of water due to the condensation of octacalcium dihydrogenhexakis (phosphate) (OCP) ) was maximum when the hydrolyzed product was obtained in solution of pH 5, though there was no weight loss in a commercially available HAp to 800 °C. The collagen content was maximum when the hydrolyzed product was obtained in s olution of pH 5. Th e correlation between the collagen content and the weight loss in TG was found. The peak temperatu re due to thermal decomposition of collagen in the hydrolyzed product was ca.3 50°C, a s well as collagen in, a b ovine tooth. However, the peak temperature was lower by c a.170°C t han that of the solubilized colla gen (ca.520 °C).
Therefore, the hydrolyzed product obtained in solution of pH 5 contained OCP and collagen in a ddition to HAp, and the collagen was thought to disperse uniformly in the hydrolyzed product as fine fibril.
