Influence of the Processes Parameters on the Properties of The ...

Chapter 5.
Characterization <strong>of</strong> Scaffolds for Connective Tissue Engineering
Blend PLGA 50:50 /P L,DL LA: 100/0 Blend PLGA 50:50 /P L,DL LA: 75/25 Blend PLGA 50:50 /P L,DL LA: 50/50
Blend PLGA 50:50 /P L,DL LA: 25/75 Blend PLGA 50:50 /P L,DL LA: 0/100
Figure 5.10: Micrographs <strong>of</strong> <strong>the</strong> P L,DL LA and PLGA 50:50 blend scaffolds.
Average Pore Diameter (m)
40 Psat = 150 P bars L,DL
LA and PLGA 50:50 Blend
35 T sat = 36.5 °C
30
25
20
15
10
5
0
t sat = 60 min
dP/dt = 25 bar/s
0 20 40 60 80 100
Fraction (%)
Figure 5.11: Average pore diameter <strong>of</strong> polymer blends as a function <strong>of</strong> P L,DL LA ratio.
3.1.2 Discussion on <strong>the</strong> Blends <strong>of</strong> P L,DL LA and PLGA 50:50
The results revealed that <strong>the</strong> pore diameter is increasing linearly with increasing amount <strong>of</strong> LA in
<strong>the</strong> blend (cf. Figure 5.11). This behaviour is conforming to <strong>the</strong> literature [Liu and Tomasko, 2007b]. The
first reason, for <strong>the</strong> decrease in pore size, can be explained by a better affinity to CO 2 <strong>of</strong> LA than GA in <strong>the</strong>
polymer blend. Secondly, low pores size can be due to high saturation pressure and low saturation
temperature with comparison to <strong>the</strong> T g <strong>of</strong> both polymers (cf Table 5.5).
3.1.3 P L,DL LA and PLGA 85:15 Blend
In <strong>the</strong> previous experiments pore sizes obtained were not very large for medical application, so we
replaced PLGA 50:50 with PLGA 85:15 in order to increase <strong>the</strong> lactic acid contents in <strong>the</strong> blend (cf. Table 5.11).
Table 5.11: Blends <strong>of</strong> PLGA 85:15 and P L,DL LA.
Blend w/w w/w w/w w/w w/w
PLGA 85:15 100% 75% 50% 25% 0%
P L,DL LA 0% 25% 50% 75% 100%
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