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

Chapter 4.
Experimental Procedures and Protocols for Analyses
<strong>of</strong> pores in <strong>the</strong> foams are present in function <strong>of</strong> <strong>the</strong> nature <strong>of</strong> polymers (P L,D LA) under <strong>the</strong> same scCO 2
conditions T sat = 55°C, P sat = 80 bar, t sat = 30 min, dP/dt=4.5 bar/s (cf. Figure 4.26).
Compairing all <strong>the</strong> graphs provide a clearer picture about <strong>the</strong> foam morphology SEM image is in
2D and it is already supposed that <strong>the</strong> pore diameter obtained from SCION ® image analysis is <strong>of</strong> a circular
pore, so if we consider pore volume <strong>the</strong> calculation <strong>of</strong> equivalent pore diameter, <strong>the</strong>re will be ano<strong>the</strong>r
hypo<strong>the</strong>sis that <strong>the</strong> pores are sphere which is not possible. Hence to make <strong>the</strong> result more close to <strong>the</strong> real
foam pore surface area is considered for calculations. SCION ® image analysis also provide information
about <strong>the</strong> nature <strong>of</strong> <strong>the</strong> pores ei<strong>the</strong>r <strong>the</strong>y are elongated, regular or irregular. Figure 4.26 (A) presents <strong>the</strong>
percentage <strong>of</strong> micro, meso and macro pores in a scaffold while Figure 4.26 (B) presents <strong>the</strong> percentage <strong>of</strong>
pore surface area. The number <strong>of</strong> macro pores are though in less percentage but <strong>the</strong> area <strong>of</strong> macro pores has
highest value. Figure 4.26 (C) presents <strong>the</strong> volume <strong>of</strong> each poreand we can see that macro pores almost
consist <strong>of</strong> 95% <strong>of</strong> total scaffold volume. The shape <strong>of</strong> pores is calculated by equation 4.2 and for P L,D LA
regular, irregular and elongated pores are 68%, 23% and 9% as presented in Figure 4.26 (D).
Micro
Meso
Macro
Pie Graph 1
Micro
Meso
Macro
Pie Graph 1
(A)-Percentage <strong>of</strong> pore quantitity.
(B)-Percentage <strong>of</strong> pore surface area.
Micro
Meso
Macro
Pie Graph 1
Elongated
Irregular
Regular
Pie Graph 1
(C)-Percentage <strong>of</strong> pore volume.
(D)-Percentage <strong>of</strong> pore types.
Figure 4.26: Pore distribution comparison in a foam with different aspects.
4.3 3D Hg Intrusion Porosity
Porosity and pore diameter <strong>of</strong> randomly selected foams were determined by AutoPore IV 9500
(cf. Figure 4.27) mercury porosimeter located at <strong>the</strong> CIRIMAT/UPS and analysis were performed by Sophie
Cazalbou. Mercury intrusion porosimeter (Pascal 140, Thermo- Quest) was used to study <strong>the</strong> pore structure
<strong>of</strong> <strong>the</strong> PLGA scaffolds. For each different pore diameter scaffolds, three measurements were performed.
Dimensions <strong>of</strong> <strong>the</strong> porous scaffolds with mass approximately 0.1 g were first measured and placed in <strong>the</strong>
ultramacropore dilatometer for out-gassing. The dilatometer was <strong>the</strong>n filled with mercury up to 1800 mm 3
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