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 />
Table 5.2: Mean diameters <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> polymers after knife mill grinding by granulometry.<br />
Polymer d (50) (m) Polymer d (50) (m)<br />
P L,D LA (PABR L 68) 161.5 PLGA 85:15 (PLG 8531) 166.1<br />
P L,DL (LA LR 704) 389.5 PLGA 85:15 (LG 857 S) 506.4<br />
PLGA 85:15 (RG 858 S) 99.7 PLGA 50:50 (RG 504) 89.5<br />
PLGA 85:15 (DL-PLG) 167.7 PLGA 50:50 (PDLG 5010) 178.2<br />
PLGA 50:50 (PLG 8523) 207.7<br />
Volume (%)<br />
20<br />
P L,D LA PAB RL 68<br />
18<br />
P L,DL<br />
LA LR 704<br />
16<br />
PLGA 50:50 RG 504<br />
14<br />
PLGA 85:15 PDLG 5010<br />
12<br />
10<br />
8 Poly (Lactide-co-glycolide) : Granulometry<br />
6<br />
4<br />
2<br />
0<br />
0.01 0.1 1 10 100 1000 10000<br />
Particle Size(m)<br />
Volume (%)<br />
10<br />
Poly (Lactide-co-glycolide) PLGA 85:15 RG 858 S : Granulometry<br />
8<br />
6<br />
PLGA 85:15 PL PLG<br />
PLGA 85:15 PLG 8523<br />
PLGA 85:15 PDLG 8531<br />
PLGA 85:15 LG 857 S<br />
4<br />
2<br />
0<br />
0.01 0.1 1 10 100 1000 10000<br />
Particle Size(m)<br />
Figure 5.1: Size distributi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> various PLAs and PLGAs after knife mill grinding.<br />
1.1.1 Experiments <strong>on</strong> Polylactide Powders by Viscosimetry.<br />
As example, we present in detail results obtained with PLGA 50:50 (RG 504) in soluti<strong>on</strong> in CCl 4 at<br />
25°C. Variati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> efflux times with <str<strong>on</strong>g>the</str<strong>on</strong>g> polymer c<strong>on</strong>centrati<strong>on</strong> and corresp<strong>on</strong>ding viscosity values are<br />
reported <strong>on</strong> Table 5.3, where t o is <str<strong>on</strong>g>the</str<strong>on</strong>g> flow time <str<strong>on</strong>g>of</str<strong>on</strong>g> pure chlor<str<strong>on</strong>g>of</str<strong>on</strong>g>orm and t is time for polymer soluti<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Ubbelohde apparatus type 3C.<br />
C<br />
(g/dl)<br />
Average<br />
Time<br />
t (sec)<br />
Table 5.3: Viscosity values <str<strong>on</strong>g>of</str<strong>on</strong>g> PLGA 50:50.<br />
Relative Specific Reduced<br />
Viscosity Viscosity Viscosity<br />
rel = t/t o sp =(t - t o )/t o red = sp /C<br />
Inherent<br />
Viscosity<br />
ln rel /C<br />
0.00 129.65 1.00 0.00 − −<br />
0.50 172.78 1.33 0.33 0.67 0.57<br />
1.00 226.65 1.75 0.75 0.75 0.56<br />
1.50 295.23 2.28 1.28 0.85 0.55<br />
2.00 359.98 2.78 1.78 0.89 0.51<br />
Variati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> efflux times with polymer c<strong>on</strong>centrati<strong>on</strong> (C) and reduced specific viscosity ( sp ) and<br />
inherent viscosity (ln rel /C) were plotted and from <str<strong>on</strong>g>the</str<strong>on</strong>g> graph <str<strong>on</strong>g>the</str<strong>on</strong>g> point <str<strong>on</strong>g>of</str<strong>on</strong>g> intersecti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> reduced viscosity<br />
and inherent viscosity at <str<strong>on</strong>g>the</str<strong>on</strong>g> Y-axis gives <str<strong>on</strong>g>the</str<strong>on</strong>g> intrinsic viscosity [] = 0.60. By using <str<strong>on</strong>g>the</str<strong>on</strong>g> Mark-Houwink<br />
Relati<strong>on</strong>ship (MHR) <br />
<br />
KM<br />
a<br />
with K = 5.43.10 -4 dl/g and a = 0.73, we obtain: M = 14 756 g/mol.<br />
Commercial Sodium hyalur<strong>on</strong>ate, or Hyalur<strong>on</strong>ic acid (HA) is comm<strong>on</strong>ly its sodium salt form. It<br />
was purchased from Javene, France. Viscosity given by <str<strong>on</strong>g>the</str<strong>on</strong>g> supplier in <str<strong>on</strong>g>the</str<strong>on</strong>g> data sheet is 2.4- 3.2 m 3 /kg,<br />
molecular weight 2.0-3.0×10 6 Dalt<strong>on</strong> and measured intrinsic viscosity as per procedure is [] = 2.92. By<br />
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