Elgayar, I, Hill, R, Chen, X et al. (2 more authors) (2017) Dielectric spectroscopy and dissolution studies of bioactive glasses. International Journal of Applied Glass Science, 8 (4). pp. 418-427. ISSN 2041-1286
Abstract
The first and rate-limiting step in the degradation of bioactive glasses is thought to be the ion exchange of hydrated protons in the external fluid with alkali metal cations in the glass. The activation energy (Eₐ) for alkali ion hopping can be followed by dielectric spectroscopy. The replacement of CaO by Na₂O resulted in a reduction in the Eₐ for ion hopping. In contrast, increasing the glass network connectivity or reducing the nonbridging oxygen content of the glass resulted in an increase in Eₐ. Substitution of K₂O for Na₂O had little influence on Eₐ. Mixing alkali metals increased the Eₐ as expected on the basis of the mixed alkali effect. There was no correlation between the Eₐ for ion hopping and the dissolution behavior of the glass. Furthermore, the activation energy for Si, Ca Na, and K ion release was found to be approximately a factor of three lower than that for ion hopping suggesting that another rate-controlling mechanism is important in the degradation of bioactive glasses. The presence of a second relaxation process suggested that bioactive glasses undergo amorphous phase separation into silica-rich and orthophosphate-rich phases and the two relaxation processes are due to ion hopping in the two phases.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 The American Ceramic Society and Wiley Periodicals, Inc. This is the peer reviewed version of the following article: Elgayar I, Hill R, Chen X, Bubb N, Wood D. Dielectric spectroscopy and dissolution studies of bioactive glasses. Int J Appl Glass Sci. 2017;8:418-427. https://doi.org/10.1111/ijag.12324; which has been published in final form at https://doi.org/10.1111/ijag.12324. This article may be used for non-commercial purposes in accordance with the Wiley Terms and Conditions for Self-Archiving. |
Keywords: | activation energy; bioactive glass; degradation; dielectric spectroscopy; mixed alkali |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Dentistry (Leeds) > Oral Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 02 Oct 2017 16:08 |
Last Modified: | 10 Aug 2020 13:19 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/ijag.12324 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:121877 |