A Critical Investigation on the Occurrence of Microwave Effects in Emulsion Polymerizations

Abstract

The existence of special microwave effects in the emulsion polymerization of styrene and methyl methacrylate with two different initiators is investigated. All the experiments are conducted in either Pyrex or silicon carbide reaction vessels employing a dedicated single‐mode microwave reactor and are monitored with a dual temperature‐measurement system consisting of an external infrared sensor and an internal fiber optical probe. The goal of this study is to study the influence of the electromagnetic field on both the decomposition rate of the radical initiators and on the emulsion polymerization itself. For both types of transformation, no direct influence of the electromagnetic field can be observed, therefore ruling out the occurrence of any type of specific or nonthermal microwave effects in these reactions.

Operation and Optimization of Microwave-Heated Continuous-Flow Microfluidics

“…MW heating is primarily driven by dipole polarization and ionic conduction inside the heated materials and directly deposits energy volumetrically, instead of relying on conventional conduction and convection. MW heating depends greatly on the dielectric properties of the materials and thereon offers the possibility of selective heating. , Because of these advantages, the MWT has been applied to a range of chemical processes, including organic synthesis, , nanoparticle synthesis, , polymerization reactions, , reactive distillation, , microfluidic processes, , and catalytic reactors. , Moreover, MW-assisted continuous-flow systems are a promising way to enable process intensification and sustainable production. − …”

Temperature-dependent complex dielectric permittivity: a simple measurement strategy for liquid-phase samples

“…MWs operate through dipole polarization and ionic conduction, depositing energy volumetrically and enabling selective heating based on the dielectric properties of materials 9 . This unique heating has been applied to various chemical processes, including organic synthesis 3 , 10 – 13 , catalytic reactors 14 , 15 , microfluidic processes 15 – 17 , nanoparticle synthesis 18 – 20 , polymerization reactions 21 , 22 , and reactive distillation 23 , 24 . In many such studies, the focus has been on MW-mediated process improvement or reactor design, especially as MWs expand beyond the laboratory scale 25 – 27 .…”