FREE-RADICAL RETROGRADE-PRECIPITATION POLYMERIZATION: A MATHEMATICAL MODELING STUDY OF POLYMERIZATION OF STYRENE IN DIETHYL ETHER

Polymerizing a monomer above the lower critical solution temperature (LCST) of its polymer-monomer-(non)solvent mixture has demonstrated better control characteristics than conventional free-radical polymerization kinetics. Reaction kinetics of polymerization in a poor solvent are strongly influenced by heat and mass transfer properties, as understood from modeling the transport phenomena in our earlier work. The study has now been extended to model the reaction kinetics in a styrene-diethyl ether system. The model was based on the CCS model for free radical polymerization, with the modification proposed by Achilias-Kiparissides. Computer simulation results agree well with those obtained from experiments carried under similar conditions, with the onset of phase separation as the only adjustable parameter. Drawbacks of the model are lack of analysis for the effect of monomer concentration and the absence of an appropriate radical trapping mechanism.