ETUDE DES SCHEMAS REACTIONNELS DE DEGRADATION THERMIQUE DES POLYMERES

N° d’ordre : 2283





THESE

présentée

pour obtenir

LE TITRE DE DOCTEUR DE L’INSTITUT NATIONAL POLYTECHNIQUE DE TOULOUSE
&
THE TITLE OF DOCTOR OF PHILOSOPHY OF THE INSTITUTE OF CHEMICAL
TECHNOLOGY, PRAGUE


École doctorale : Energétique et Dynamique des Fluides
Spécialité : Energétique et transferts – Systèmes et Procédés


Par M. Jaroslav BLAŽEK


Titre de la thèse : ETUDE DES SCHEMAS REACTIONNELS DE DEGRADATION
- français THERMIQUE DES POLYMERES
- anglais STUDY OF THE REACTION KINETICS OF THE THERMAL
DEGRADATION OF POLYMER
- tchèque TERMICKÁ DEGRADACE ORGANICKÝCH MATERIÁLŮ


Soutenue le 11 Novembre 2005 devant le jury composé de :

M. Bohumil KOUTSKÝ Président

MM. Didier LECOMTE, Petr BURYAN Directeurs de thèse
André FONTANA, Pavel STRAKA, Ivan VÍDEN Rapporteurs
František HRDLIČKA Membre
Yannick SOUDAIS Membre
Florent LEMORT Membre
Josef VEJVODA Membre

















— 2 —

































— 3 — Contents

1. INTRODUCTION ................................................................................................................. 11
2. THEORETICAL BACKGROUNDS .................................................................................... 12
2.1 Pyrolysis ........................................................................................................................ 12
2.1.1 Various possible methods of use of plastic polymers....................................... 14
2.2 Thermal analysis ........................................................................................................... 17
2.2.1 Thermogravimetric analysis.............................................................................. 19
2.3 Kinetics .......................................................................................................................... 24
2.3.1 Isothermal vs. non-isothermal kinetics and other issues................................. 28
2.4 Polymers ........................................................................................................................ 37
2.4.0 Studied polymers................................................................................................ 48
2.4.1 Lignin .................................................................................................................. 48
2.4.2 Cellulose.............................................................................................................. 60
2.4.3 EVA ..................................................................................................................... 62
2.4.4 PS ........................................................................................................................ 64
2.4.5 PVC ..................................................................................................................... 69
3. EXPERIMENTAL PART – STUDY OF THE KINETICS OF THE THERMAL
DEGRADATION OF POLYMERS.......................................................................................... 72
3.1 Materials and experimental apparatuses..................................................................... 72
3.2 PART A – Kinetic study of the thermal degradation of polymers –
isoconversional method (model-free method) ........................................................... 75
3.2.1 TGA data treatment ........................................................................................... 75
3.2.2 Kinetic model in literature ................................................................................ 81
3.2.2.1 Lignin ......................................................................................................... 81
3.2.2.2 Cellulose..................................................................................................... 83
3.2.2.3 Ethylene vinyl acetate............................................................................... 85
3.2.2.4 Polystyrene................................................................................................ 89
3.2.2.5 Polyvinyl chloride..................................................................................... 92
3.2.3 Analysis of experimental results ....................................................................... 97
3.2.3.1 Lignin ......................................................................................................... 97
3.2.3.2 Cellulose................................................................................................... 100
3.2.3.3 Ethylene vinyl acetate............................................................................. 101
3.2.3.4 Polystyrene.............................................................................................. 103
3.2.3.5 Polyvinyl chloride................................................................................... 105
3.2.4 Discussion and conclusions ............................................................................. 107
3.3 PART B – Kinetic study of thermal degradation of polymers – numerical
resolution of kinetic equations obtained from reaction pseudo-schemes
(model-fitting method) .............................................................................................. 111
3.3.1 Lignin ................................................................................................................ 111
3.3.2 EVA ................................................................................................................... 125
3.3.3 Study of the degradation kinetics of binary mixtures of polymers .............. 135
3.3.4 Simulation of kinetic models in MatLab......................................................... 156
3.3.5 FTIR analysis of released gases....................................................................... 166
3.3.6 Discussion and conclusions ............................................................................. 178
4. DISCUSSION AND CONCLUSION .................................................................................. 179
5. REFERENCES.................................................................................................................... 181
6. REFERENCES – selected papers on kinetics................................................................... 190
— 4 — Appendices

Appendix A: FTIR working protocol..................................................................................... 197
Appendix B: Experimental results, EVA kinetics................................................................. 200
Appendix C: Detailed description of the thermobalance ..................................................... 203
Appendix D: Description of the FTIR spectrometer............................................................ 206
Appendix E: Tables for Part 1............................................................................................... 208
Appendix F: Figures for Part 1.............................................................................................. 219
Appendix G: Polymer generalities ......................................................................................... 257
Appendix H: List of publications and presentations of professional activities .................. 259
Appendix I: Notation used...................................................................................................... 261



List of figures

Fig. 1: Plastic materials susceptible to recycling .................................................................... 14
Fig. 2: Industrial pyrolysing unit P.I.T. – PYROFLAM® with energy valorization ........... 15
Fig. 3: Thermal conductivity of furnace atmosphere gases.................................................... 22
Fig. 4: Linear, branched, and network polymer configuration.............................................. 39
Fig. 5: Chain polymerization and step polymerization........................................................... 43
Fig. 6: Free-radical polymerization: example of styrene........................................................ 44
Fig. 7: Polystyrene prepared by free-radical polymerization................................................ 44
Fig. 8: Polymerization of terephthalic acid and ethylene glycol............................................ 45
Fig. 9: Polyethylene terephthalate ........................................................................................... 46
Fig. 10: Cut through a young black conifer............................................................................. 49
Fig. 11: Lignin monomer (coniferine and syringine) .............................................................. 50
Fig. 12: Formulae of three principal lignin alcohols .............................................................. 50