Rheo-Raman: A Promising Technique for In Situ Monitoring of Polymerization Reactions in Solution

Abstract

The use of a laboratory-made rheo-Raman device for continuous in situ monitoring of free-radical polymerization of acrylic acid in aqueous solution is reported for the first time. Combining a mixer-type rheometer with a quartz outer cylinder to a Raman spectrometer, this original experimental device has allowed us to overcome three current challenges of polymerization reaction monitoring. First, monomer conversion, polymer formation, and viscosity of reaction medium were continuously monitored with well-defined conditions (composition, temperature, and flow), using Couette analogy. Second, direct correlation between macroscopic viscosity and medium composition was established (accounting for the continuous variation of molar mass distribution). Third, using a mixer-type rheometer provided scalable results, in terms of stirring conditions.