Chass, G.A.

Greaves, G.N.

Yue, Yuanzheng

VBN (Videnbasen)  Aalborg Universitets forskningsportal

    Aalborg UniversitetFollowing the setting of glass-ionomer bio-cements and mechanical toughness, tomodel the cementitious processGreaves, G.N.; Chass, G.A.; Yue, YuanzhengPublished in:The 24th International Congress on Glass - AbstractsPublication date:2016Document VersionPublisher's PDF, also known as Version of recordLink to publication from Aalborg UniversityCitation for published version (APA):Greaves, G. N., Chass, G. A., & Yue, Y. (2016). Following the setting of glass-ionomer bio-cements andmechanical toughness, to model the cementitious process: An invited talk. In The 24th International Congresson Glass - Abstracts (pp. 34). International Commission on Glass (ICG).General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: April 30, 2017Following the setting of glass-ionomer bio-cements and mechanical toughness, to model the cementitious process G. N. Greaves1,2, G. A. Chass3, Y. Z. Yue1,4,  1State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, China 2Department of Materials Science and Metallurgy, University of Cambridge, United Kingdom 3School of Biological and Chemical Sciences, Queen Mary University of London, London, UK 4Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark gng25@cam.ac.uk  Bio-cements, notably glass-ionomer cements, have been in widespread use for over 40 years in dentistry and medicine. They are chemically complex, with starting ingredients comprising an alumino-fluoro-phospho-silicate glass powder and aqueous acrylic acid. The glass is also heavily phase separated: individual phases identified with alumina-silicate, Ca-F-P-rich, and Ca-F-rich phases.1) Progress in improving the mechanical properties of glass-ionomer cements, however, lags behind the toughness needed for permanent implants. A significant impediment to improvement has been reliance on conventional mechanical failure methods, which are necessarily retrospective.   Through the novel use of neutron Compton scattering (NCS), which directly measures atomic cohesion, we show how it is possible to follow fracture toughness in situ during setting.  Combining NCS with differential scanning calorimetry (DSC) and coherent terahertz spectroscopy (CTS), a comprehensive picture of the setting process can be obtained. In particular fluctuations in interfacial configurations during chelation between glass and polymer are observed.2) Compared to conventional mechanical methods, we find that the setting of this cement is not monotonic, but characterised by abrupt features in the development of toughness, not previously directly detected (Figure 1). Moreover we find evidence that setting processes are driven by THz collective vibrations at the hybrid interface between glass and polymer (Figure 2). By harnessing Quantum Chemical calculations we are now able to show how the development and dynamics of these processes can be understood in the context of changing atomic configurations at the altering surface of the glass, all of which provides clues by which to improve the mechanical performance of bio-cements, and, by inference, other cementitious materials.     Figure 1. Developing Fracture Toughness of bio-cement as a function of setting time obtained from Neutron Compton Scattering. The Fracture Toughness of the starting Glass and Polymer are shown for comparison.  CP- Coupling Point between the glass and polymer; ISP- Initial Setting Point of GIC; ISZ- Intermediate Stress Zone.       Figure 2. Geometry-optimised DFT interface model (left), identifying the glass cluster, terminated with OH- and PAA polysalt complexes, linked via Al polyhedra. Anticlockwise sequence 1-3 shows different stages of chelation, culminating in Al(V) stable arrangement (right), modelling the hybrid interface between glass and polymer.   1) M. T. Pedersen, K. V. Tian, C. Dobó-Nagy, G. A. Chass, G. N. Greaves and Y. Z. Yue, Phase separation in an ionomer glass: insight from calorimetry and phase transitions, J. Non-Cryst. Solids 415 (2015) 24–29. 2) K. V. Tian, B. Yang, Y. Z. Yue, D. T. Bowron, J. Mayers, R. S. Donnan, C. Dobó-Nagy, J. W. Nicholson, D. C. Fang, A. L. Greer, G. A. Chass and G. N. Greaves, Atomic and vibrational origins of mechanical toughness in bio-cement during setting, Nat. Commun. 6 (2015) 8631.  

Following the setting of glass-ionomer bio-cements and mechanical toughness, to model the cementitious process:An invited talk

http://vbn.aau.dk/files/231982479/Greaves_Abstract_ICG2016.pdf

Following the setting of glass-ionomer bio-cements and mechanical toughness, to model the cementitious process:An invited talk

Abstract

Similar works

Full text

Available Versions

VBN (Videnbasen) Aalborg Universitets forskningsportal