1 H and 31 P MAS NMR Spectra of Hydroxyapatite Powders Dried At 80 °C

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Context 1

... order to obtain further information on the bonding of hydroxyapatite, 31 P and 1 H MAS-NMR measurements were performed. In a first stage, 31 P MAS-NMR analyses (on samples dried at 80°C) were carried out (Fig. 2-a). As expected for a hydroxyapatite phase, the 31 P NMR signal for pure HA gave rise to a single phosphorus peak around 2.79 ±0.1 ppm which is tentatively assigned to the PO 4 3-signal and a single carbonate groups (PO 4 3----CO 3 2-) peak of low intensity around 0.97 ppm. It may be noted that, in this study, no protonated phosphate ...

Context 2

... PO 4 3-signal and a single carbonate groups (PO 4 3----CO 3 2-) peak of low intensity around 0.97 ppm. It may be noted that, in this study, no protonated phosphate (e.g. HPO 4 2-ions giving rise to an additional contribution typically around 1.4 (W.P. Rothwell 1980) has been clearly detected in any sample. The NMR peak near -0.18 and 1.05 ppm ( fig. 2-b) can be assigned to apatitic OHions from the hydroxyapatite phase (J.P. Yesinowski et al. 1987). Powder X-ray diffraction (XRD) studies were carried out to identify phases and assess the phase-purity and crystallinity of Ca,Papatite powders and sintered discs. The purity of the synthesized nanocrystalline apatite of the initial powder ...