RAFT copolymerization of styrene (Sty) and 2-(dimethyl amino)ethylacrylate (DMAEA) in dimethylformamide

 Novel approaches are made in the online monitoring of reaction kinetics in the case of copolymeric polyelectrolytes synthesized by ‘living’ polymerization. The goal of the study is to investigate polyelectrolyte properties of gradient copolymers produced by reversible addition-fragmentation chain transfer (RAFT) by online monitoring of the polymerization reaction of styrene (Sty) and 2-(dimethyl amino)ethylacrylate (DMAEA) in dimethylformamide. A recent approach used to monitor different types of properties of a polymer during its synthesis, consisting in simultaneous withdrawal and diluting of the reactor solution with different solvents was applied in this work. Thus, dilution with water of the first stream taken from the reactor allows conductivity measurements to be made and their results used in the copolymer characterization. On the other hand, dilution with dimethylformamide of a second stream withdrawn from the reactor allows conversion, copolymer mass, reduced viscosity, and composition to be determined based on light scattering measurements combined with spectroscopic and viscometric measurements. Trends in composition drift and the effect of the charged comonomer on the degree of livingness of the copolymer are studied.  Polyelectrolyte properties of the end-products are characterized by the Automatic Continuous Mixing (ACM). Mass distribution and polydispersity indexes are computed based on the results from Size Exclusion Chromatography (SEC). Illustrated in the figure below are the dilution scheme used in ACOMP for this project (upper part) and the commoner concentrations determined from combining results from conductivity and UV measurements (lower part).