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

List <strong>of</strong> Figures
Figure 1.1: Structures <strong>of</strong> selected biodegradable polymers ............................................................................. 12
Figure 1.2: Stereo-forms <strong>of</strong> lactides. ............................................................................................................... 13
Figure 1.3: Ring opening polymerization <strong>of</strong> lactide to polylactide. ................................................................ 14
Figure 1.4: Different ways <strong>of</strong> producing PLA. ................................................................................................ 14
Figure 1.5: Schemaic syn<strong>the</strong>sis <strong>of</strong> poly(lactide-co-glycolide). ........................................................................ 17
Figure 1.6: Electron micrograph and chemical HA structure. ......................................................................... 19
Figure 2.1: Procedure <strong>of</strong> solvent casting/particulate leaching. ........................................................................ 29
Figure 2.2: Procedure <strong>of</strong> ice particle–leaching. ............................................................................................... 30
Figure 2.3: Procedure <strong>of</strong> gas foaming/salt-leaching method. .......................................................................... 31
Figure 2.4: Procedure <strong>of</strong> scaffolds by gel-pressing method. ........................................................................... 32
Figure 2.5: Schematic procedure <strong>of</strong> <strong>the</strong> processing <strong>of</strong> PLGA microsphere scaffolds. .................................... 33
Figure 2.6: Schematic procedure for manufacturing <strong>of</strong> scaffolds with <strong>the</strong> particle-aggregated technique. .... 33
Figure 2.7: Schematic preparation processing <strong>of</strong> scaffold by <strong>the</strong> freeze-drying method. ............................... 34
Figure 2.8: Schematic preparation processing <strong>of</strong> <strong>the</strong>rmally induced phase separation method. ..................... 35
Figure 2.9: Schematic procedure showing <strong>the</strong> fabrication <strong>of</strong> scaffolds by centrifugation method and
photographs <strong>of</strong> variously shaped scaffolds. ................................................................................. 36
Figure 2.10: Reaction <strong>of</strong> injectable <strong>the</strong>rmosensitive gel.................................................................................. 37
Figure 2.11: Schematic stepwise representation <strong>of</strong> <strong>the</strong> polymeric foaming using hydrocarbon porogen. ...... 39
Figure 2.12: Schematic diagram <strong>of</strong> <strong>the</strong> fused deposition modelling (FDM) system. ...................................... 40
Figure 2.13: Schematic diagram <strong>of</strong> <strong>the</strong> 3D Bioplotter TM system. .................................................................... 40
Figure 2.14: Schematic diagram <strong>of</strong> <strong>the</strong> Stereolithography (SLA) system. ...................................................... 41
Figure 2.15: Schematic diagram <strong>of</strong> <strong>the</strong> phase change jet printing system, <strong>the</strong> Model-Maker II. .................... 42
Figure 2.16: Phase diagrams P-T and -P for a pure CO 2 ............................................................................... 43
Figure 2.17: ScCO 2 experimental apparatus (A) CO 2 tank, (B) syringe pump and (C) pressure vessel. ........ 45
Figure 2.18: Schematic representation <strong>of</strong> <strong>the</strong> supercritical fluid foaming process. ......................................... 46
Figure 2.19: Schematic presentation for scaffold generation during scCO 2 foaming. .................................... 47
Figure 2.20: Evolution <strong>of</strong> process parameters and <strong>the</strong> occurring phenomena during <strong>the</strong> foaming with time. 48
Figure 2.21: Schematic <strong>of</strong> <strong>the</strong> phenomenon <strong>of</strong> fragmentation in <strong>the</strong> co-grinding. .......................................... 59
Figure 2.22: Different stages <strong>of</strong> agglomeration during <strong>the</strong> co-grinding: (a) adhesion, (b) coating and (c)
agglomeration. ............................................................................................................................. 59
Figure 3.1: Differential scanning calorimetry. ................................................................................................ 62
Figure 3.2: Thermograms <strong>of</strong> two P L LAs <strong>of</strong> different Mw. .............................................................................. 63
Figure 3.3: Characteristic variation <strong>of</strong> glass transition in PLGA. ................................................................... 63
Figure 3.4: Schematic representation <strong>of</strong> <strong>the</strong> Ubbelohde viscosimeter. ............................................................ 65
Figure 3.5: Variation with concentration <strong>of</strong> reduced specific and inherent viscosities <strong>of</strong> P L,D LA (LR 704). .. 66
Figure 3.6: (A) Mastersizer 2000 (Malvern Instruments) (B) Schematic diagram showing <strong>the</strong> main
components <strong>of</strong> a laser diffraction particle size analyzer. ............................................................. 67
Figure 3.7: Scheme <strong>of</strong> laser diffraction <strong>of</strong> a spherical particle. ....................................................................... 68
Figure 3.8: Three dimensional model <strong>of</strong> scattering from a dipole. .................................................................. 68
Figure 3.9: Scattering patterns <strong>of</strong> two particles <strong>of</strong> a different size. ................................................................. 69
Figure 3.10: Principles <strong>of</strong> Fresnel’ diffraction (A) and Fraunh<strong>of</strong>er’ diffraction (B and C). ............................ 69
Figure 3.11: Desorption <strong>of</strong> CO 2 from PLGA 50:50 with time. ............................................................................ 70
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