Concentration effects in the base-catalyzed hydrolysis of oligo(ethylene glycol)- and amine-containing methacrylic monomers

Abstract

Concentration effects in the base-catalyzed hydrolysis of water-soluble methacrylates (3-(N,N-dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs)) have been studied. These monomers are rapidly hydrolyzed in the presence of bases at the room temperature in dilute aqueous solutions, but the reaction rate decreases sharply in highly concentrated solutions. A clear correlation was found between a form of the viscosity isotherm for DMAEMA solutions and the concentration dependence of the autocatalytic hydrolysis rate which indicates the connection of process kinetics with the structure of solutions. These data should be considered when carrying out homo- and copolymerization of the previously mentioned monomers in aqueous solutions.

Exploring the Long-Term Hydrolytic Behavior of Zwitterionic Polymethacrylates and Polymethacrylamides

“…Moreover, they consider typically short periods only, that is, a few days at most. The majority of the systematic studies seem to have been conducted on the hydrolytic stability of the underlying monomers [27,28,29,30,31], but not on the polymers, assuming tacitly that the difference would be small. Accordingly, the literature assessments of the stability of antifouling polymers often represent mere assumptions, or are based on singular observations for which the precise experimental conditions are often not disclosed.…”

Physicochemical properties of oligo(ethylene glycol) (meth)acrylates

“…В широком интервале начальных концентраций ЭГМ (580% мас.) после введения NaOH, взятой в недостатке по отношению к мономеру, через несколько минут происходит эквимольное количеству щелочи образование метакриловой кислоты (продукта гидролиза), которая нейтрализует щелочь, и гидролиз резко тормозится [33,36]. Если изначально ввести NaOH в избытке по отношению к ЭГМ, то за несколько минут происходит полное расходование мономера.…”

“…Эффект концентрации ЭГМ при этом не проявляется. Но при исследовании гидролиза ОЭГ(М)А при катализе NaOH (0,4 ммоль/г) был выявлен концентрационный эффект -скорость реакции резко снижается в высококонцентрированных растворах макромономера [36]. Так, для 50%-ного водного раствора расход МОЭГМ-12 через 3 мин составил 89%, а в 83%-ном растворе макромономера гидролизу подверглось всего 6% эфира за то же время.…”

“…Концентрационные эффекты наблюдались и в случае катализа гидролиза третичными аминами (рис. 7) [36]. На начальном этапе увеличения концентрации мономеров (до 1520% мас.)…”

Surfactant-free synthesis of layered double hydroxide-armored latex particles

“…We first added HEMA to the LDH suspension and stirred for 30 minutes in order to modify its surface, but the system lost stability once the reaction started after the addition of St. HEMA is indeed known to undergo fast hydrolysis in diluted alkaline solutions even at room temperature. 49 The released MAA molecules have likely interacted with the LDH surface, 50 which promoted LDH aggregation and subsequent latex destabilization. To confirm this assumption, increasing amounts of MAA, with molar concentrations equivalent to the amount of HEMA used in the Pickering emulsion polymerization experiments, were introduced into the LDH suspension.…”