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• Recyclable – they undergo melt and solidify cycles • Easy to repair by welding, solvent bonding, etc. • Postformable Disadvantages of thermoplastics • Thermoplastics are prone to creep • They have poor melt flow characteristics Characteristics of thermoset polymers • Upon application of heat, liquid resin becomes rigid via vitrification process • End polymer is less temperature sensitive than thermoplastics • Crosslinked network structure (formed from chemical bonds) exists throughout part • Crosslinking provides thermal stability such that polymer will not melt or flow upon heating – Examples: epoxy, unsaturated polyesters, vinyl esters, phenol formaldehyde, bismaleimide, urethane. Advantages and disadvantages of thermosets Advantages of thermosets • Low resin viscosity • Good fiber wet-out • Excellent thermal stability once polymerized • Chemically resistant • Creep resistant Disadvantages of thermosets • Brittle — 42 —
• Non-recyclable via standard techniques • Must mold polymer in shape of final part – not postformable Classification Based on Polymerization Reactions There are two fundamental polymerization reactions: chain polymerization and step polymerization (Fig. 5). This classification is of particular importance to thermosetting systems that polymerize in situ when used in processes. – chain polymerization – step polymerization Fig. 5: Chain polymerization and step polymerization. Chain (or Addition) Polymerization Chain polymerization is characterized by the presence of a few active sites, which react and propagate through a sea of monomers. Sometimes called also chain-reaction polymerization, it requires an initiator to start the growth of the reaction. The largest family of polymers [PSRC], vinyl polymers, are produced by chain polymerization reactions from vinyl monomers. A good example is the free-radical polymerization of styrene, which is initiated by a free radical (R) that reacts with styrene. The compound that is formed still is a free radical, which can react again (see Fig. 6). — 43 —
Page 1 and 2: N° d’ordre : 2283 THESE présent
Page 3 and 4: — 3 —
Page 5 and 6: Appendices Appendix A: FTIR working
Page 7 and 8: Appendix D Fig. D-1: Michelson inte
Page 9 and 10: Acknowledgements Firstly I must exp
Page 11 and 12: 1. Introduction Accumulation of var
Page 13 and 14: Oil is produced by condensation of
Page 15 and 16: There are 4 main techniques of recy
Page 17 and 18: 2.2 Thermal analysis A typical meth
Page 19 and 20: Tab. 1: Principal thermoanalytical
Page 21 and 22: a point of inflection at a faster h
Page 23 and 24: can react with porcelain or alumina
Page 25 and 26: The use of Arrhenius equation which
Page 27 and 28: their kinetic parameters are false.
Page 29 and 30: statistical analysis allows one to
Page 31 and 32: The ability to handle multi-step re
Page 33 and 34: The solution for avoiding these pro
Page 35 and 36: quantifying the experimental result
Page 37 and 38: 2.4 Polymers The word polymer has i
Page 39 and 40: - linear - branched - network Fig.
Page 41: * Hydrogen bonds (hydrogen bonding
Page 45 and 46: Polymers formed via this process in
Page 47 and 48: [Mathias]: proteins, polypeptides,
Page 49 and 50: Fig. 10: Cut through a young black
Page 51 and 52: The first stage of lignin polymeris
Page 53 and 54: H 2 COH HC O HCOH OMe OMe HC CH CH
Page 55 and 56: Notwithstanding, lignins can be mad
Page 57 and 58: monomer CH 2 OH HC O HO CH second m
Page 59 and 60: Lignin Lignin CH 2 O, Na 2 SO 3 CH
Page 61 and 62: Cellulose is a component part ensur
Page 63 and 64: 1) Extrusion of films: food packagi
Page 65 and 66: HIPS or Impact polystyrene Commerci
Page 67 and 68: H * C C H n* 2 Fig. 23: Elementary
Page 69 and 70: 2.4.5 PVC PVC is the second most ut
Page 71 and 72: As a matter of fact, PVC is more an
Page 73 and 74: In all experiments, samples of EVA
Page 75 and 76: 3.2 Part A Kinetic study of the the
Page 77 and 78: Now, several experiments using vari
Page 79 and 80: Otherwise, its value would have to
Page 81 and 82: 3.2.2 Kinetic model in literature 3
Page 83 and 84: 3.2.2.2 Cellulose From the point of
Page 85 and 86: 3.2.2.3 Ethylene vinyl acetate At p
Page 87 and 88: HC H O H 2 H H 2 2 H 2 C C C C C C
Page 89 and 90: 3.2.2.4 Polystyrene The PS degradat
Page 91 and 92: formation of gases that add to thos
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naphtalene and anthracene) is forme
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them to find the third stage that w
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3.2.3 Analysis of experimental resu
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degradation. Thus, the evaluation o
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3.2.3.3 Ethylene vinyl acetate The
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3.2.3.4 Polystyrene The pyrolysis b
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3.2.3.5 Polyvinyl chloride The pyro
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3.2.4 Discussion and conclusions In
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The thermal degradation consists of
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3.3 Part B Kinetic study of thermal
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Operating methods The type of ligni
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Tab. 16: Comparison of literature a
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Ad 1) Initialisation of parameters:
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77 Theoretical and experimental evo
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Reaction order as a function of tem
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Globally, results connected to acti
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3.3.2 Ethylene vinyl acetate Let us
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graph of mass loss rates of the sum
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parameters are the ones from the pa
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This equation and its coefficients
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Tab. 22: Calculation of VA percenta
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3.3.3 Study of the degradation kine
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Study of the mixture EVA/PS This ch
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EVA/PS mixture Here, three stages o
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Generally speaking, DTG value incre
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Let us remind the initial hypothesi
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The values of relative errors of fr
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The results concerning the order of
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Study of the mixture EVA/PVC and EV
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Tab. 33: Mass loss, DTG, and DTG pe
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dm1 : 30 % at 300°C dm2 : 20 % at
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Xa(T,i)*DTGa(i), (36) where Xa(T,i)
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Chart of PVC modelling: Fig. 50: Co
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dCellulose = k 0 .exp(-E a /RT) (1
Page 161 and 162:
The problem of incoherence between
Page 163 and 164:
Fig. 56: Comparison of experimental
Page 165 and 166:
Conclusion on MatLab simulation res
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Principle of infra-red spectrometry
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Analysis of results of FTIR for pur
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5. time = 1,419.01 s, T = 510°C. T
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2. time = 922.60 s, T = 344°C. The
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Weak peaks of acetic acid can be ob
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• In the pyrolysis of mixtures, n
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4. Discussion and conclusion In the
Page 181 and 182:
5. References ACS, American Chemica
Page 183 and 184:
Day, M., Cooney, J. D., Touchette-B
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Lecomte, D., Bodoira, N., Mise au p
Page 187 and 188:
Oliveira, A. A. M., Kaviany, M., Hr
Page 189 and 190:
Turi, E. A., editor, Thermal charac
Page 191 and 192:
Cao, J., Mathematical studies of mo
Page 193 and 194:
Kissinger, H.E., Variation of peak
Page 195 and 196:
Poutsma, M. L., Fundamental reactio
Page 197 and 198:
Appendices Appendix A Working proto
Page 199 and 200:
are visualized. This tool is very p
Page 201 and 202:
for EVA + EVA* stage 1, T d,max1 [
Page 203 and 204:
Appendix C Detailed description of
Page 205 and 206:
Furnace The furnace used within the
Page 207 and 208:
The above mentioned data were obtai
Page 209 and 210:
Tab. E-3: Cellulose pyrolysis frequ
Page 211 and 212:
Tab. E-7: EVA 25 frequency factors,
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Tab. E-11: Temperatures at various
Page 215 and 216:
Tab. E-15: Activation energies of t
Page 217 and 218:
Tab. E-19: PVC pyrolysis frequency
Page 219 and 220:
Appendix F - Figures for PART A -
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Appendix G - Polymer generalities -
Page 259 and 260:
Appendix H List of publications and
Page 261 and 262:
Appendix I - Notation used A Freque
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