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

Introduction and outline
functioning of the classical polymerization process and why fundamental research of the vinyl
chloride suspension polymerization at laboratory scale is very limited.
Through this perspective, the interest of microreactors seems intriguing. It has been confirmed that the
miniaturizations offer new methods for accurately obtaining and controlling polymer particles with
narrow size distribution. These research studies have been described in the literature (Marcati et al.,
2010; Serra et al., 2007; Seo et al., 2005). Polymerization in a two-phase dispersion system, such as
suspension reactions, is the main method for obtaining polymer particles and several microreactor
related studies have been conducted on this subject. Various authors have thus proved that droplet
microfluidics is an appropriate tool for polymerization reactions.
Performing the suspension polymerization of vinyl chloride in microreactor enables the good control
of the monomer droplet dimensions. Besides, the continuous monitoring of the polymerization
reaction phenomena would guide to a better knowledge of the reaction kinetics. In addition, the
reaction may be investigated in difficult conditions in terms of pressure or temperature with a minimal
amount of reagents thus increasing the safety of the process. This research stage, considered as a
fundamental approach might open an opportunity to a better reaction control and optimisation.
Without even mentioning the fact that it would certainly represent an innovation in the field of PVC
studies.
The main objective of this work is to acquire fundamental information regarding the polymerization
phenomena such as the perricellular membrane formation, radical agglomeration, thus the PVC grain
morphology. Also a kinetic study might furnish data regarding the intrinsic reaction rates. The use of
microreactors would certainly allow enlightening of the phenomena taking place at the scale of a
micrometer monomer droplet.
This PhD thesis is structured in four chapters. The first one consists of a literature review on the
suspension vinyl chloride polymerization, analysing the elements that might change the reaction
course. An overview of the kinetic models existing in the bibliography is presented. Finally, the
application of microreactors to polymer synthesis is described, accompanied with literature examples.
Chapter two is focused on the hydrodynamics of vinyl chloride/water system in fused silica
microchannels. The experimental pilot is described, designed especially for this purpose, allowing
high pressure and temperature conditions, ensuring also complete safety with regard to the
12