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

More documents

Recommendations

Info

Chapter 4. Experimental Procedures and Protocols for Analyses 3.2 Differential Scanning Calorimetry The transition temperature and change in specific heat capacity were measured by a NETZSCH DSC 204 Phoenix ® Set Up under a N 2 atmosphere. The DSC measuring cell consists <strong>of</strong> a cylindrical highconductivity silver block with an embedded heating coil for broad <strong>the</strong>rmal symmetry (3D symmetry) in <strong>the</strong> sample chamber, <strong>the</strong> cooling ports for liquid nitrogen or compressed air cooling and a cooling ring for connection <strong>of</strong> <strong>the</strong> intra-cooler (also with simultaneous liquid nitrogen cooling). For all <strong>the</strong> experiments, 3 – 10 mg were accurately weighed by a digital microbalance and sealed into an aluminium sample pan (pans are crimped close with sample press). An empty aluminium pan was used as <strong>the</strong> reference sample. The DSC heating and cooling rates were controlled at 10°C/min, and all experiments were carried out under a nitrogen purge. Following steps are made during <strong>the</strong> analysis, ‣ Calibrating <strong>the</strong> instrument with indium ‣ Selecting <strong>the</strong> pan type and material and preparing <strong>the</strong> sample ‣ Creating or choosing <strong>the</strong> test procedure and entering sample and instrument information through <strong>the</strong> TA instrument control s<strong>of</strong>tware ‣ Setting <strong>the</strong> purge gas flow rate, <strong>the</strong>n loading <strong>the</strong> sample and closing <strong>the</strong> cell lid ‣ Starting <strong>the</strong> experiment and <strong>the</strong>n obtaining <strong>the</strong> data and <strong>the</strong>rmograms. Schematic presentation <strong>of</strong> <strong>the</strong> <strong>the</strong>rmal analysis is presented in Figure 4.19 B Compressed sample pan C Sample data Furnace program screen Aluminum pan press Aluminum top lid Tweezers Reference cup Liquid N 2 tank DSC sample chamber Test start window Experimental curve Aluminum base pan A DSC sample preparing accessories NETZSCH DSC 204 Phoenix® Set Up D Foam E Computer display and monitoring unit Balance to weigh sample Polymer powder Thermogram with T g Figure 4.19: DSC analysis flow sheet <strong>of</strong> polymer material and foam. - 100 -
Chapter 4. Experimental Procedures and Protocols for Analyses 3.3 Contact Angle Measurement The used apparatus Digidrop Contact Angle GBX (cf. Figure 4.20) makes it possible to carry out measurements <strong>of</strong> contact angle per drop posed on substrate by recording image per image <strong>of</strong> <strong>the</strong> sessile drop. The drop is allowed to flow and equilibrate with <strong>the</strong> surface. (A)- Apparatus (B)- Syringe with specific liquids (C)- Liquid deposition sequence Figure 4.20: Goniometer GBX used for contact angle measurement. This goniometer is constituted by: A motorized movable plate on which a compressed powder pellet is deposited, A light source and a digital CCD camera that can acquire photographs <strong>of</strong> <strong>the</strong> system drop / solid at equilibrium (24 frames/sec), A motorized syringe to deposit a liquid drop, volume controlled from <strong>the</strong> surface <strong>of</strong> <strong>the</strong> solid sample to be analyzed, An acquisition system to record wetting angle and process photographs using <strong>the</strong> s<strong>of</strong>tware on digital images DIGIDROP. Two different fitting procedures have been used to determine <strong>the</strong> best shape <strong>of</strong> <strong>the</strong> drop and thus <strong>the</strong> correct contact angle (cf. Figure 4.21). The contour method toge<strong>the</strong>r with <strong>the</strong> height-width approach, are appropriate for small contact angle measurements. The circle-method shapes <strong>the</strong> drop in <strong>the</strong> form <strong>of</strong> a circular arc, while <strong>the</strong> height-width-method determines <strong>the</strong> height and <strong>the</strong> width <strong>of</strong> a rectangle that surrounds <strong>the</strong> drop. A manual method, <strong>the</strong> tangent-method or <strong>the</strong> conic section method, fits a conic section equation on <strong>the</strong> drop shape where θ acts as <strong>the</strong> angle at <strong>the</strong> three-phase contact point. A benefit here is that <strong>the</strong> contact angle range is much wider (between 10 and 100°), and that <strong>the</strong> fitting procedure does not assume that contact angles on both sides are equal, resulting in two different contact angles (θ left and θ rigth ). (A) (B) Figure 4.21: (A): Schematic diagram and (B): Two methods for determining <strong>the</strong> contact angle. - 101 -
Page 1 and 2:
Institut National Polytechnique de
Page 4:
iii Dedicated to My Fathe</
Page 7 and 8:
pleased I was to work with all memb
Page 10 and 11:
Publications and Conferences The wo
Page 12 and 13:
Nomenclature and Abbreviations Abbr
Page 14:
ρ p Pellet density Splitting (Bra
Page 17 and 18:
Chapter 2 .........................
Page 19 and 20:
6.2.1 Surface Tensions of</
Page 21 and 22:
4.1 Effect of <str
Page 23 and 24:
3.2 Experiments on PLA/Waxes Scaffo
Page 26 and 27:
List of Figures Fi
Page 28 and 29:
Figure 4.28: Incremental Intrusion
Page 30 and 31:
Figure 6.36: Micrographs of
Page 32 and 33:
Figure 8.32: Slice images o
Page 34 and 35:
List of Tables Tab
Page 36 and 37:
Table 8.1: Polymers with different
Page 38 and 39:
iological performance. Biocompatibi
Page 40 and 41:
Thesis Introduction Chapter 1 Chapt
Page 42 and 43:
Chapter 1. Polylactide Based Bio-Ma
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Chapter 2. Processes</stron
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87: Chapter 2. Processes</stron
Page 98 and 99: Chapter 3. Analytical Methods and D
Page 102 and 103: . Chapter 3. Analytical Methods and
Page 124 and 125: Chapter 4. Experimental Procedures
Page 148 and 149: Chapter 5 - 112 -
Page 150 and 151: Chapter 5. Characterization <strong
show all

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

Create successful ePaper yourself

Delete template?

Save as template?