Vinyl chloride polymerization in microdroplet reactor - Les thèses en ...

Chapter I : Bibliographic review
polymer phase until the limiting conversion is reached. Thus, a model valid for the entire conversion
range describes the two-phase polymerization before X f and single phase after conversion value X f , in
good agreement with experimental values. In fact, the main features of VCM polymerization are
summarized in the scheme in Figure I- 9:
Two phase scheme for
S-PVC
Radical formation in
monomer phase
Radical formation in
polymer phase
Radical migration
Chain propagation in
monomer phase
Chain propagation in
polymccer phase
Chain termination in
monomer phase
Chain termination in
polymer phase
Polymer
Figure I- 9: Radical history of VCM polymerization proposed by Xie et al. (1991a)
I.D.4) Heat removal
The VCM polymerization is highly exothermic, as illustrated in Table I- 4. The difference of adiabatic
temperature corresponds to a reaction taking place without any heat exchange with the exterior, so it is
the rise of the temperature in a monomer/polymer medium (bulk polymerization).
Monomer Physical state [a] Temperature (°C) -∆H R (kJ.mol -1 ) -∆H R (kJ.kg -1 ) +∆T ad (°C)
Ethylene g c 25 101.5 3620 1810
Butadiene l c 25 73 1350 676
Acrylonitrile l c’ 74.5 76.5 1423 721
Methyl
l c 74.5 55.5 550 277
methacrylate
Vinyl acetate l c 74.5 88 1022 511
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