The role of alumina in aluminoborosilicate glasses for use in glass-ionomer cements

被引:16
|
作者
Pires, Ricardo A. [1 ,2 ]
Abrahams, Isaac [3 ]
Nunes, Teresa G. [1 ,2 ]
Hawkes, Geoffrey E. [3 ]
机构
[1] Inst Super Tecn, Dept Mat Engn, P-1049001 Lisbon, Portugal
[2] Inst Super Tecn, Ctr Quim Estrutural, P-1049001 Lisbon, Portugal
[3] Univ London, Ctr Mat Res, Sch Biol & Chem Sci, London E1 4NS, England
关键词
SOLID-STATE NMR; MULTINUCLEAR MAGNETIC-RESONANCE; SODIUM ALUMINOBORATE GLASSES; AL-27; MAS-NMR; SITE CONNECTIVITIES; PHASE-SEPARATION; RANGE ORDER; NA-23; NMR; SPECTROSCOPY; B-11;
D O I
10.1039/b822285a
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Aluminoborosilicate glasses of general composition (0.14 - x/2.2)SiO(2):(0.07 - x/4.2)B(2)O(3):(0.09 - x/3.3)Na(2)O:0.40CaO: xAl(2)O(3) (0.00 <= x <= 0.30) were synthesised using standard melt quenching methods and analysed by (11)B, (23)Na, (27)Al and (29)Si solid-state nuclear magnetic resonance (NMR) spectroscopy. Calculations based on electroneutrality considerations were used to check the consistency of the NMR assignments in both glasses and cements. Glass - ionomer cement (GIC) formation was tested with all the prepared glass compositions, but only the samples with higher concentrations of Al(2)O(3), x >= 0.20, produced sustainable cements. The compressive strengths (CS) of the cements varied from 66.7 to 74.2 MPa, although the differences were not statistically significant. The leaching of aluminium from the glass into the cement matrix varied between 6 and 12 mol%. It is proposed that aluminium plays a key role in glass - ionomer cements, not only through leaching of Al(3+) ions from the glass into the cement matrix during formation, but also through reinforcement of the resulting cement by the residual glass particles which have high alumina content and confer greater mechanical strength.
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页码:3652 / 3660
页数:9
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