Inverse microemulsion copolymerization of butyl acrylate and acrylamide: kinetics, colloidal parameters and some model applications

Abstract

The inverse microemulsion copolymerization of acrylamide and butyl acrylate initiated by ammonium peroxodisulphate, a water-soluble initiator, and stabilized by anionic emulsifiers sodium bis-2ethylhexylsulfosuccinate and sodium dodecylsulphate (SDS) has been studied. An increase of SDS concentration was observed to increase both the rate of polymerization and the particle size. The average number of radicals per particle (n) is much below 0.5, which indicates desorption of monomeric radicals from polymer particles. The exit (desorption) rate constants k des (cm 2 s −1 ) and k des (s −1 ) were evaluated as a function of SDS concentration (or the particle size) according to the Ugelstad/O'Toole (I), Nomura (II) and Gilbert (III) models. The value of k des (s −1 ) decreases with increasing particle size (or SDS concentration) for all three (I, II and III) models. A complex trend appears for k des (cm 2 s −1 ): the Ugelstad/O'Toole model estimates a decrease, the Nomura model finds no variation and the Gilbert model estimates even a slight increase in k des with increasing SDS concentration.

On the preparation of composite poly(butyl acrylate)/carbon nanotube nanoparticles by miniemulsion polymerization of butyl acrylate

“…[27][28][29][30][31] The constants were calculated as described in our previous papers 32 using the data summarized in Tables 1-3 and the literature data and constants in Table 4. [33][34][35][36] The calculated exit rate constants k¢ des (cm 2 s À1 ) and radical entry rates r a (Ms À1 ) are shown in Tables 5 and 6.…”

Kinetics and colloidal parameters of miniemulsion polymerization of butyl acrylate

“…This indicates that the exit of monomeric radicals from particles increases with decreasing particle size and increased crosslinked density of polymer particles. The exit (desorption) rate constants k ′ des (cm 2 s −1 ) and k des (s −1 ) were calculated to obtain more information about the radical exit events with three different models: the Ugelstad/O'Toole approach (I), the Nomura model (II) and the Gilbert model (III), as described in our previous paper 36. The Ugelstad/O'Toole, Nomura and Gilbert models were directly applied to miniemulsion polymerization of BuA.…”

“…The adsorption of the radicals depends on the particle size and number of particles as well, while the desorption is mainly dependent on the particle size. The increase of the number of particles and decrease of the particle size with [MIM] result in the decrease of a ( a ≈ d p 3 / N p ) 36. On the other hand, the average number of radicals per particle ( n̄ ) with increasing amount of MIM generally decreases.…”

Inverse Miniemulsion Polymerization of Unsaturated Monomers

“…The kinetics of inverse miniemulsion polymerization and copolymerization of acryalmide was reported by Capek et al [19][20][21][22][23][24]. The conversion-time data for the inverse miniemulsion polymerization of acrylamide initiated by ammonium peroxodisulfate (APS) at different emulsifier (Tw 85) concentrations are shown in Figure 8.1 [21].…”

“…The dependence of the rate of copolymerization of AAm and crosslinker (N,N'-methylenebis(acrylamide) (MBA) vs. conversion is described by a curve with the two rate intervals -similar to that observed for the emulsion polymerization of AAm [23,24]. The maximal rate of polymerization slightly increases with increasing the crosslinker (MBA) concentration; R max °c [MBA] X=016 (APS).…”