EFFECT OF ORGANOPHOSPHATES ON THE FORMATION OF MAGNESIUM-FREE WHITLOCKITE

Abstract

Objective of the present study was to synthesize Mg-free whitlockite (WH) particles using organophosphates with different alkyl chain lengths via a solvothermal reaction. The effects of the organophosphates and their Ca/P molar ratio on the formation of WH were investigated. With increasing alkyl chain length of the organophosphate and increasing Ca/P molar ratio, the dominant phase changed from WH to hydroxyapatite (HA). This result suggests that the organophosphates exhibited different hydrolysis rates. With all of the organophosphates, WHs were obtained only at a Ca/P molar ratio of 0.25. In addition, an analysis of the local structure using H and P nuclear magnetic resonance spectroscopy indicated that the WH contained protonated phosphate (HPO4 ) and trace amount of HA subphase. (Received Jul 12, 2021; Accepted Sept 15, 2021)