The structure of phosphate glass biomaterials from neutron diffraction and P-31 nuclear magnetic resonance data

Pickup, D. M. and Ahmed, I. and Guerry, P. and Knowles, J. C. and Smith, Mark E. and Newport, R. J. (2007) The structure of phosphate glass biomaterials from neutron diffraction and P-31 nuclear magnetic resonance data. Journal of Physics: Condensed Matter, 19 (41): 415116. ISSN 0953-8984

Abstract

Neutron diffraction and P-31 nuclear magnetic resonance spectroscopy were used to probe the structure of phosphate glass biomaterials of general composition (CaO)(0.5-x) (Na2O)(x) (P2O5)(0.5) (x = 0, 0.1 and 0.5). The results suggest that all three glasses have structures based on chains of Q(2) phosphate groups. Clear structural differences are observed between the glasses containing Na2O and CaO. The P-O bonds to bridging and non-bridging oxygens are less well resolved in the neutron data from the samples containing CaO, suggesting a change in the nature of the bonding as the field strength of the cation increases Na+ -> Ca2(+). In the (CaO)(0.5)(P2O5)(0.5) glass most of the Ca2+ ions are present in isolated CaOx polyhedra whereas in the (Na2O)(0.5) (P2O5)(0.5) glass the NaOx polyhedra share edges leading to a Na-Na correlation. The results of the structural study are related to the properties of the (CaO)(0.4) (Na2O)(0.1) (P2O5)(0.5) biomaterial.