Apatitic Calcium Orthophosphates and Related Compounds for Biomaterials Preparation

The authors show that to obtain well chemically defined apatitic bioceramics and to know the possible transformations of this material during sintering, it is necessary to prepare a good starting material. Moreover, they show that it is possible to prepare a new organic-inorganic phosphate compound....

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Bibliographic Details
Published in:Annals of the New York Academy of Sciences 1988-06, Vol.523 (1), p.115-130
Main Authors: BONEL, GILBERT, HEUGHEBAERT, JEAN-CLAUDE, HEUGHEBAERT, MONIQUE, LACOUT, JEAN LOUIS, LEBUGLE, ALBERT
Format: Article
Language:English
Subjects:
Ammonium Hydroxide
Apatites
Biocompatible Materials - analysis
Biocompatible Materials - chemical synthesis
Calcium - analysis
Calcium Compounds
Calcium Hydroxide
Calcium Phosphates - analysis
Calcium Phosphates - chemical synthesis
Chemical Phenomena
Chemistry, Physical
Hot Temperature
Hydroxides
Hydroxyapatites - analysis
Hydroxyapatites - chemical synthesis
Models, Chemical
Organophosphorus Compounds
Oxides
Phosphates - analysis
Spectrophotometry, Infrared
X-Ray Diffraction
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Summary:The authors show that to obtain well chemically defined apatitic bioceramics and to know the possible transformations of this material during sintering, it is necessary to prepare a good starting material. Moreover, they show that it is possible to prepare a new organic-inorganic phosphate compound. The precipitation of apatite in an aqueous medium at boiling temperature was studied using the methodology of experimental design. Independent variables were the volume of NH4OH in phosphate solution, the volume of NH4OH in calcium solution, and the time of precipitation; the response was the atomic Ca/P ratio of the obtained precipitate. A continuous variation of this ratio from 1.63 to 1.73 is observed. Implications of this result to the preparation of pure HA: Ca10(PO4)6(OH)2 is given. Moreover, when Ca/P greater than 1.67, HA reacts with Ca(OH)2 (after heating at 1000 degrees C in air for some days) to give rise to a single phase described as a modified HA (MHA), a Ca/P ratio of 1.75, an a value of 9.373 +/- 0.002 A, and a c value of 6.884 +/- 0.002 A. The reactivity (time versus temperature) of the MHA is described. If the precipitation of the calcium phosphate is realized at 37 degrees C in a water-ethanol medium in the presence of A2EP, a new apatite, chemically bonded to the organic molecule by pooling phosphate groups, is obtained.
ISSN:0077-8923
1749-6632
DOI:10.1111/j.1749-6632.1988.tb38506.x