Biomedical Engineering Reference
In-Depth Information
Table 2.3
Non-45S5 bioactive glass compositions in weight percentages.
Name
ID
SiO
2
Na
2
OCaO
2
O
5
SrO K
2
OMgO
NovaBone
45S5 Bioglass
45.0
24.5
24.7
6.0
-
-
-
BonAlive
S53P5
53.0
23.0
20.0
4.0
-
-
-
13-93
53.0
6.0
20.0
4.0
-
12.0
5.0
Sr10
44.1
24.0
21.6
5.9
4.4
-
-
ICIE1-10Sr
48.2
26.5
18.9
2.5
3.9
-
-
100
Tc
Tm
0Sr
Tg
50
10Sr
25Sr
0
50Sr
75Sr
−
50
100Sr
−
100
400
600
800
Temperature
(
1000
1200
°
C
)
Figure 2.4
Effect of substituting calcium with strontium on thermal properties
using DTA on a series of bioactive glasses. (Reprinted with permission from [4]
Copyright (2010) Royal Society of Chemistry.)
so an upward peak is an exothermic transition (bond-forming) and a
trough is an endothermic transition (bond-breaking). The characteristic
glass transition temperature (
T
g
) and the melting temperature (
T
m
)
both decrease with increasing strontium [13]. The crystallisation onset
temperature (
T
c
) is an exception, in that it approaches a minimum at
50% strontium substitution (perhaps approaching a metasilicate eutectic
point), then increases again in the Sr-rich glasses.
Magnesium is particularly effective at widening the sintering win-
dow, but also affects bioactivity. Magnesium is typically considered
a network modifier in silicate glasses, but it can partially act as an