Effect of calcium source on structure and properties of sol-gel derived bioactive glasses

Yu, B. and Turdean-Ionescu, C.A. and Martin, R.A. and Newport, Robert J. and Hanna, J.V. and Smith, M.E. and Jones, J.R. (2012) Effect of calcium source on structure and properties of sol-gel derived bioactive glasses. Langmuir, 28 (50). pp. 17465-17476. ISSN 0743-7463. (doi:https://doi.org/10.1021/la303768b) (Full text available)

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The aim was to determine the most effective calcium precursor for synthesis of sol–gel hybrids and for improving homogeneity of sol–gel bioactive glasses. Sol–gel derived bioactive calcium silicate glasses are one of the most promising materials for bone regeneration. Inorganic/organic hybrid materials, which are synthesized by incorporating a polymer into the sol–gel process, have also recently been produced to improve toughness. Calcium nitrate is conventionally used as the calcium source, but it has several disadvantages. Calcium nitrate causes inhomogeneity by forming calcium-rich regions, and it requires high temperature treatment (>400 °C) for calcium to be incorporated into the silicate network. Nitrates are also toxic and need to be burnt off. Calcium nitrate therefore cannot be used in the synthesis of hybrids as the highest temperature used in the process is typically 40–60 °C. Therefore, a different precursor is needed that can incorporate calcium into the silica network and enhance the homogeneity of the glasses at low (room) temperature. In this work, calcium methoxyethoxide (CME) was used to synthesize sol–gel bioactive glasses with a range of final processing temperatures from 60 to 800 °C. Comparison is made between the use of CME and calcium chloride and calcium nitrate. Using advanced probe techniques, the temperature at which Ca is incorporated into the network was identified for 70S30C (70 mol % SiO2, 30 mol % CaO) for each of the calcium precursors. When CaCl2 was used, the Ca did not seem to enter the network at any of the temperatures used. In contrast, Ca from CME entered the silica network at room temperature, as confirmed by X-ray diffraction, 29Si magic angle spinning nuclear magnetic resonance spectroscopy, and dissolution studies. CME should be used in preference to calcium salts for hybrid synthesis and may improve homogeneity of sol–gel glasses.

Item Type: Article
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Langmuir [Field not mapped to EPrints] C2 - 23171477 [Field not mapped to EPrints] AD - Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom [Field not mapped to EPrints] AD - Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom [Field not mapped to EPrints] AD - School of Engineering and Applied Science, Aston Research Centre for Healthy Ageing, Aston University, Birmingham B4 7ET, United Kingdom [Field not mapped to EPrints] AD - School of Physical Science, University of Kent, Canterbury CT2 7NH, United Kingdom [Field not mapped to EPrints] AD - Vice-Chancellor's Office, University House, Lancaster University, LA1 4YW, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Bone regeneration, Calcium nitrate, Calcium salts, Different precursors, High temperature treatments, Highest temperature, Inhomogeneities, Inorganic/organic hybrid, Magic angle spinning nuclear magnetic resonance spectroscopy, Probe technique, Processing temperature, Room temperature, Silica networks, Silicate network, Sol-gel glass, Sol-gel hybrids, Structure and properties, Bioactive glass, Calcium chloride, Calcium silicate, Hybrid materials, Magic angle spinning, Nitrates, Nuclear magnetic resonance spectroscopy, Silica, Silicates, Sol-gel process, X ray diffraction, Calcium, calcium, calcium chloride, calcium derivative, calcium nitrate, calcium silicate, glass, nitrate, silicate, article, chemistry, phase transition, Calcium, Calcium Chloride, Calcium Compounds, Glass, Nitrates, Phase Transition, Silicates
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QD Chemistry > QD478 Solid State Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Giles Tarver
Date Deposited: 11 Feb 2015 13:55 UTC
Last Modified: 16 Apr 2019 10:04 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46954 (The current URI for this page, for reference purposes)
Newport, Robert J.: https://orcid.org/0000-0002-2365-992X
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