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The effect of MgO/TiO 2 on structural and crystallization behavior of near invert phosphate-based glasses.
- Source :
-
Journal of biomedical materials research. Part B, Applied biomaterials [J Biomed Mater Res B Appl Biomater] 2020 Apr; Vol. 108 (3), pp. 674-686. Date of Electronic Publication: 2019 Jun 07. - Publication Year :
- 2020
-
Abstract
- Varying formulations in the glass system of 40P <subscript>2</subscript> O <subscript>5</subscript> ─(24 - x)MgO─(16 + x)CaO─(20 - y)Na <subscript>2</subscript> O─yTiO <subscript>2</subscript> (where 0 ≤ x ≤ 22 and y = 0 or 1) were prepared via melt-quenching. The structure of the glasses was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), micro Raman and solid-state nuclear magnetic resonance (NMR) spectroscopies. The thermal properties and the activation energy of crystallization (E <subscript>c</subscript> ) were measured using thermal analysis and the Kissinger equation, respectively. The glass forming ability of the formulations investigated was seen to decrease with reducing MgO content down to 8 mol% and the glass stability region also decreased from 106 to 90°C with decreasing MgO content. The activation energy of crystallization (E <subscript>c</subscript> ) values also decreased from 248 (for 24 mol% MgO glass) to 229 kJ/mol (for the 8 mol% MgO content) with the replacement of MgO by CaO for glasses with no TiO <subscript>2</subscript> . The formulations containing less than 8 mol% MgO without TiO <subscript>2</subscript> showed a strong tendency toward crystallization. However, the addition of 1 mol% TiO <subscript>2</subscript> in place of Na <subscript>2</subscript> O for these glasses with less than 8 mol% MgO content, inhibited their crystallization tendency. Glasses containing 8 mol% MgO with 1 mol% TiO <subscript>2</subscript> revealed a 12°C higher glass transition temperature, a 14°C increase in glass stability against crystallization and a 38 kJ/mol increase in E <subscript>c</subscript> in comparison to their non TiO <subscript>2</subscript> containing counterpart. NMR spectroscopy revealed that all of the formulations contained almost equal percentages of Q <superscript>1</superscript> and Q <superscript>2</superscript> species. However, FTIR and Raman spectroscopies showed that the local structure of the glasses had been altered with addition of 1 mol% TiO <subscript>2</subscript> , which acted as a network modifier, impeding crystallization by increasing the cross-linking between phosphate chains and consequently leading to increased E <subscript>c</subscript> as well as their glass forming ability.<br /> (© 2019 Wiley Periodicals, Inc.)
- Subjects :
- Calcium Compounds chemistry
Cross-Linking Reagents chemistry
Crystallization
Magnetic Resonance Spectroscopy
Molecular Structure
Oxides chemistry
Sodium Compounds chemistry
Spectroscopy, Fourier Transform Infrared
Spectrum Analysis, Raman
Structure-Activity Relationship
Thermodynamics
Transition Temperature
Magnesium Oxide chemistry
Phosphates chemistry
Titanium chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1552-4981
- Volume :
- 108
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of biomedical materials research. Part B, Applied biomaterials
- Publication Type :
- Academic Journal
- Accession number :
- 31172669
- Full Text :
- https://doi.org/10.1002/jbm.b.34421