P. Schaad et al., INHIBITION OF DISSOLUTION OF HYDROXYAPATITE POWDER BY ADSORBED ANIONIC POLYMERS, Colloids and surfaces. A, Physicochemical and engineering aspects, 83(3), 1994, pp. 285-292
The effect of the presence in solution of neutral or anionic hydrosolu
ble polymers on the kinetics of dissolution of hydroxyapatite powder (
HAP) is analysed at a constant pH of 5 and under well-controlled condi
tions. Four polymers are studied. It is shown that the polymers that a
re able to be adsorbed induce a decrease in the rate of dissolution wh
ich strongly depends on the chemical structure of the polymers. Chemic
al groups with the ability to bind calcium ions, such as phosphate and
phosphonate groups, are particularly efficient. The results are inter
preted with the use of a recently proposed apatite dissolution model w
hich assumes the formation, at the apatite interface, of an ionic semi
permeable layer produced by the adsorption of calcium ions. According
to this model, adsorbed polymers increase the ionic capacity of the in
terface.