Reaction Calorimetry for the Development of Ultrasound-Induced Polymerization Processes in CO2-Expanded Fluids

• Published in: Macromolecular symposia Vol. 248; no. 1; pp. 182 - 188
• Main Authors: Kemmere, Maartje F., Kuijpers, Martijn W.A., Keurentjes, Jos T.F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.02.2007; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Carbon dioxide; cavitation; Exact sciences and technology; Fluid dynamics; Fluid flow; Fluids; molecular weight distribution; Organic polymers; Physicochemistry of polymers; Polymerization; Polymers; Polymethyl methacrylates; Preparation, kinetics, thermodynamics, mechanism and catalysts; pressurized carbon dioxide; radical polymerization; ultrasound; Viscosity; Sonochemical reaction; State of the art; Free radical polymerization; Methyl methacrylate polymer; Polymerization under pressure; Competitive reaction; Liquid carbon dioxide; Chemical degradation; Ultrasound; Chemical reaction kinetics
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200750219

A strong viscosity increase upon polymerization hinders radical formation during an ultrasound‐induced bulk polymerization. Since CO2 acts as a strong anti‐solvent for most polymers, it can be used to reduce the viscosity of the reaction mixture. In this work, a process for the ultrasound‐induced polymerization in CO2‐expanded fluids has been developed. Temperature oscillation calorimetry has been applied to study the influence of CO2 on the viscosity during the ultrasound‐induced polymerization. In contrast to polymerizations in bulk, the results show that a low viscosity is maintained during polymerization reactions in CO2‐expanded methyl methacrylate (MMA). As a consequence, a constant or even increasing polymerization rate is observed when pressurized CO2 is applied. Moreover, the ultrasound‐induced polymer scission in CO2‐expanded MMA is demonstrated, which appears to be a highly controlled process. Finally, a preliminary sustainable process design is presented for the production of 10 kg/hour pure PMMA (specialty product) in CO2‐expanded MMA by ultrasound‐induced initiation.