Influence of the partial substitution of CaO with MgO on the thermal properties and in vitro reactivity of the bioactive glass S53P4

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Massera J, Hupa L, Hupa M
Publisher: ELSEVIER SCIENCE BV
Publication year: 2012
Journal: Journal of Non-Crystalline Solids
Journal acronym: J NON-CRYST SOLIDS
Volume number: 358
Issue number: 18-19
Start page: 2701
End page: 2707
Number of pages: 7
ISSN: 0022-3093


Abstract

The influence of up to 4 mol% substitution of MgO for CaO on the properties of the bioactive glass S53P4 was studied. Thermal analysis, hot stage microscopy and X-ray diffractometry were utilized to measure the thermal properties and the crystallization characteristics of the glasses. The in-vitro bioactivity was measured by immersing the glasses for 4 h to one week in simulated body fluid. The formation of silica rich and hydroxyapatite layers was assessed from FTIR spectra analysis and SEM images of the glasses surface. Increasing substitution of MgO for CaO decreased the glass transition, the onset and endset of melting and the fusion temperatures. The activation energies for glass transition and crystallization also decreased from (790 +/- 30) to (407 +/- 30) kJ/mol and from (283 +/- 30) to (145 +/- 30) kJ/mol, respectively, indicating a decrease in bond length and an increase in bond strength with progressive MgO at the expense of CaO. All glasses dissolved identically in SBF during the first 24 h of immersion with subsequent formation of hydroxyapatite at the grain surfaces. The thickness of the surface layers decreased with increasing MgO content. For longer duration of immersion, the glasses with the highest MgO contents exhibited a slower reaction tendency, with simulated body fluid, than the Mg-free glass. These changes in the glass structure and in-vitro properties may be of interest for products from bioactive glasses with large surface area to volume ratio.


Keywords

Bioactive glasses, In-vitro bioactivity, Structural properties, Thermal properties

Last updated on 2019-17-11 at 03:45