Application of online infrared spectroscopy to study the kinetics of precipitation polymerization of acrylic acid in supercritical carbon dioxide

Abstract

The kinetics of precipitation polymerization of acrylic acid in supercritical CO2 is monitored by in situ FTIR spectroscopy.

Online Monitoring of Polymerizations: Current Status

“…[21] The application of online FTIR spectroscopy was also investigated by Destarac and coworkers [22] to study the kinetics of precipitation polymerization of acrylic acid (AA) in supercritical carbon dioxide (scCO 2 ), and comparative studies were performed in toluene for reference. For both solvents an induction period was observed where only very little polymeri- [32] ©2010American Chemical Society.…”

Volumetric properties of carbon dioxide + acrylic acid binary in the context of supercritical precipitation polymerization

“…With this volumetric data, excess volume plots at high pressure for the mixture were obtained, resulting in negative deviations. The experimental window swept in this work is in accordance with the polymerization conditions described previously in the literature for AA in CO 2 [7,11,13,14]. The phase boundaries were correlated with a simple model.…”

“…Desorption of the surfactant from particles and removal of volatile organic compounds (VOCs), like residual monomer and/or solvent from the polymer, are among the drawbacks of these processes [10]. Precipitation polymerization is a stabilizer-free process in which both initiator and monomer are soluble in the reaction medium while the polymer is insoluble and precipitates as it is formed and allows the preparation of high-purity polymer powders [11].…”

“…On an industrial scale, it is produced either by solution free-radical polymerization in water or in heterogeneous media [12]. AA has been polymerized successfully in CO 2 by precipitation polymerization in a batch reactor [2,11,13,14] and by continuous precipitation polymerization in Continuous Stirred Tank Reactors (CSTR) [7]. To properly design supercritical reactors, it is important to consider the phase behavior of the initial reactive mixture.…”

Continuous Kinetic Sampling of Flow Polymerizations via Inline UV–Vis Spectroscopy

“…Therefore, several online and inline methods in combination with flow chemistry have emerged during the last years. They range from analytic devices like size exclusion chromatography (SEC), [ 6,7 ] electrospray ionization mass spectroscopy [ 8 ] or NMR [ 9,10 ] to inline spectroscopic methods like IR [ 11,12 ] or UV–vis. [ 13 ] Most of these techniques are known from batch analytics, where especially NMR and SEC are obligatory for characterization of polymeric intermediates and products.…”