Effect of Ionization on Aqueous Phase Radical Copolymerization of Acrylic Acid and Cationic Monomers

Abstract

The synthesis of polyampholytes by radical copolymerization of cationic and anionic monomers in aqueous solutions is investigated using in situ NMR to track monomer conversions and relative consumption rates. The batch copolymerization kinetics of t w o c a t i o n i c m o n o m e r s , 2 -( m e t h a c r y l o y l o x y e t h y l )t r i m e t h y l a m m o n i u m c h l o r i d e ( T M A E M C ) a n d 3 -(methacryloylaminopropyl)trimethylammonium chloride (MAP-TAC), with fully ionized acrylic acid (NaA) are compared with each other and also to their copolymerization with nonionized acrylic acid (AA). TMAEMC, with its ester functionality, exhibits higher reactivity than MAPTAC, with both of the cationic monomers preferentially incorporated into the copolymers relative to both AA and NaA. The increased relative incorporation rate of the cationic comonomers when copolymerized with NaA compared to AA is attributed to the electrostatic repulsion to addition of NaA monomer to an NaA radical and the favored cross-propagation steps between oppositely charged species. The data set is used to estimate system reactivity ratios that accurately capture the dependence of comonomer composition drift on initial monomer concentrations and composition.

Positive Charge Influences on the Surface Interactions and Cohesive Bonding of a Catechol-Containing Polymer

“…These mechanical data indicate that the polymer Tg’s were above room temperature. Further insights on architecture can be made from a prior study with the similar monomers [3-(methacryloylamino)­propyl] trimethylammonium chloride (MAPTAC) and acrylic acid (AA) . Reactivity ratios were seen to be consistently below 1, indicative of random copolymerization behavior.…”

“…Further insights on architecture can be made from a prior study with the similar monomers [3-(methacryloylamino)propyl] trimethylammonium chloride (MAPTAC) and acrylic acid (AA). 53 Reactivity ratios were seen to be consistently below 1, indicative of random copolymerization behavior. Coupled with DSC traces showing no obvious signs of multiple thermal events, we can infer that the copolymers used here are random in nature.…”

The influence of monomer ionization and hydrolysis on the radical polymerization kinetics of 2-(dimethylamino)ethyl methacrylate in aqueous solution

“…A recent study supports this hypothesis showing a greater reactivity of ionized compared to non-ionized AA when copolymerized with the cationic monomer TMAEMC. 58…”

“…A recent study supports this hypothesis showing a greater reactivity of ionized compared to nonionized AA when copolymerized with the cationic monomer TMAEMC. 58 The influence of inhibition could still be seen in the data collected at pH of 10.1 and 9.0 when initiator concentration was increased to 0.4 wt% at 50 °C; however, for pH of 8.0, 22% of the DMAEMA had already reacted before the first data acquisition (Fig. 9a and Fig.…”

Superlubricity of pH-responsive hydrogels in extreme environments

“…Conversely, the pH of the pre-polymerized solution significantly impacts the microstructure of copolymerized hydrogels. There have been many studies examining the effects of pH on the reactivity ratios of acrylamide and acrylic acid monomers ( Cabaness et al, 1971 ; Rintoul and Wandrey, 2005 ; Riahinezhad et al, 2013 ; Ezenwajiaku and Hutchinson, 2021 ). While the actual values of these reactivity ratios are highly dependent on the reaction conditions (e.g., temperature, pH, ionic concentration, monomer concentration, etc.…”