Free Radical Copolymerization of Methyl methacrylate and N‐Phenyl maleimide in 1‐Butyl‐3‐methylimidazolium tetrafluoroborate

Abstract

Summary:We investigated the free radical copolymerization of methyl meth-acrylate (MMA) and N-phenyl maleimide (NPI) in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4 ). Dimethyl formamide (DMF) was used as reference solvent. The influence of the ionic liquid (IL) on the polymerization rate r p , the molecular weights M n , the copolymer composition, the glass-transition temperature and the rheological behavior of the copolymers was studied. In [BMIM]BF 4 r p strongly decreases with increasing initial concentration of NPI and becomes even lower than in DMF for 70 to 90 mol% NPI in the monomer feed. In addition, M n of the copolymers produced in the IL strongly decreases with increasing NPI content, but is always higher than in DMF.

New ionic liquids with hydrolytically stable anions as alternatives to hexafluorophosphate and tetrafluoroborate salts in the free radical polymerization and preparation of ion-conducting composites

“…[3][4][5][6][14][15][16][17] The influence of ILs on the kinetics of polymerization processes is related to the decrease in the activation energy 5,18,19 and the respective increase in the propagation rate. 4,5,[18][19][20][21][22] At the same time, the rate of termination decreases, 4,5,20,22,23 sometimes even by an order of magnitude, with the increase of IL concentration. 18 The increase in the propagation rate is generally attributed to the increased polarity of the ionic medium in comparison with that of the organic solvents that are traditionally used, whereas the decrease in the termination rate is assumed to be due to the increased viscosity of ILs.…”

“…18 The increase in the propagation rate is generally attributed to the increased polarity of the ionic medium in comparison with that of the organic solvents that are traditionally used, whereas the decrease in the termination rate is assumed to be due to the increased viscosity of ILs. [3][4][5][6]18,20,24,25 Andrzejewska et al 21 detected the phenomenon of viscosity synergism in dimethacrylate monomer/IL mixtures (that is, the viscosity of the mixture is higher than the simple additive combination of the viscosities of the two components); this phenomenon can have an important role in the kinetics of the reaction because the possibility of the gel effect is higher in the IL solution than in the bulk monomer. Schmidt-Naake et al 5 partly explained the reduction of the activation energy of propagation by the specific interaction of ethyl acrylate with ILs and the formation of H-bonds between both the monomer molecules and growing radical chains and the cations and anions of the ILs.…”

Ionic Liquids as Advantageous Reaction Media for Free Radical Polymerization

“…Ionic liquids have been investigated in radical polymerization since several years as summarized and discussed in several reviews . Compared to the use of traditional solvents, rates of polymerization are mostly higher in ionic liquids, and molecular weights are often increased .…”

Formation of Polymer–Ionic Liquid Gels Using Vapor Phase Precursors

“…The equilibrium concentration of HEMA within the polymer–IL sample was 1 ± 1 wt %, which was less than the equilibrium concentration within the pure IL (4 ± 1 wt %), demonstrating that the solubility of the HEMA monomer decreases with increasing polymer concentration, which could explain the formation of lower molecular weight chains with increasing time. The broadening of the molecular weight distribution with increasing polymer concentration has also been observed by Schmidt–Naake and coworkers, who showed that the molecular weight of poly(methyl methacrylate) polymerized in 1-ethyl-3-methyl-imidazolium ethylsulfate ([EMIM][EtSO 4 ]) decreased with increasing reaction time, which they attributed to an increase in viscosity, leading to a decrease in the propagation rate constant . It is likely that the formation of lower molecular weight polymers with increasing deposition time is due to both a decrease in the monomer concentration in the IL layer and a decrease in the propagation rate.…”

“…The broadening of the molecular weight distribution with increasing polymer concentration has also been observed by Schmidt−Naake and coworkers, who showed that the molecular weight of poly(methyl methacrylate) polymerized in 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO 4 ]) decreased with increasing reaction time, which they attributed to an increase in viscosity, leading to a decrease in the propagation rate constant. 57 It is likely that the formation of lower molecular weight polymers with increasing deposition time is due to both a decrease in the monomer concentration in the IL layer and a decrease in the propagation rate.…”