Effects of Ionization on Tacticity and Propagation Kinetics in Methacrylic Acid Polymerization

Abstract

Theoretical calculations have been performed to model the propagation kinetics and ionization behavior of methacrylic acid (MAA) from first principles. The pK a values of various COOH groups of chemical species with direct relevance to MAA polymerization have also been calculated. At a given temperature, syndiotacticity increases with solvent polarity and ionization, and herein we show that accurate quantum chemistry can correctly account for these effects and explain their origin in terms of the changing structure of the charged propagating species.

Superabsorbent Poly(isoprenecarboxylate) Hydrogels from Glucose

“…However, the rate of the polymerization slowed as the percentage of sodium carboxylates in the feed was increased. This phenomenon is also reported for (meth)­acrylic acid and sodium (meth)­acrylate copolymerizations. − …”

Mechanistic Perspectives on Stereocontrol in Lewis Acid-Mediated Radical Polymerization

“…ordinary monomers rotation around the terminal bond is very rapid compared with propagation. We have recently confirmed this postulate in theoretical studies on methacrylic acid propagation 98 and would argue that it should be applicable to most "ordinary" monomer systems, including (meth)acrylates and (meth)acrylamides. For most monomers, pro-meso and pro-racemo configurations are nearly degenerate and similarly reactive and hence radical polymerization affords predominantly atactic polymer.…”

Interplay Between Applied Force and Radical Attack in the Mechanochemical Chain Scission of Poly(acrylic acid)

“…As PAA contains a protic side group, explicit water solvation was deemed important. For instance, the electronic characteristics of PAA are known to be altered by the presence of an αradical, 40 and hydrogen bonding is known to affect the heat of polymerization of protic polymers such as PAA. 41 In addition, the introduction of explicit water ensures that the conformers used in this study are consistent with aqueous solvation.…”