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