Emulsion polymerization of an epoxy-acrylate emulsion stabilized with polyacrylate. i. influence of salt, initiator, neutralizing amine, and stirring speed

Abstract

The past decade has seen the development of high‐performance epoxy‐acrylate coatings. Some of these coatings are used exclusively as can coatings. To improve chemical resistance, emulsion polymerization in the presence of the dispersed epoxy resin can be conducted. Replicated factorial designs were designed to investigate some of the factors that contribute to the performance and stability of the epoxy‐acrylate coating. The factors investigated in this study were: the type and amount of neutralizing amine, the type of initiator, the presence or absence of salt, and the stirring speed of the impeller. The measured responses for the experimental design were particle size, particle size distribution, and conversion. It has been shown in this study that the type of amine used to neutralize the polyacrylic stabilizer significantly influenced the observed responses probably by acting as chain transfer agent during polymerization. The addition of salt significantly affected the observed responses by shielding the surface charges on the particle surface that impart stability to the latex through electrostatic repulsion. Stirring speed of the impeller and the type of initiator as factors in the range investigated do not influence the kinetics or the particle size and polydispersity to any great extent either on their own or in combination with other factors. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1347–1360, 1999

Emulsion polymerization of an epoxy-acrylate emulsion stabilized with polyacrylate. II. Using the results of statistically designed experiments to deduce a possible polymerization mechanism

“…The solids content varied from 60 mass % for PA4, 52.26 mass % for PA1, to 46.22 mass % for PA3. The sample handling procedure as well as the actual emulsion polymerization has been described previously 1…”

“…Recently we have reported on a number of factors that influence the stability of an epoxy‐acrylate emulsion 1. This article is a continuation of that work, and will consider the effects of monomer, epoxy, and polyacrylate levels on particle size, polydispersity, and conversion of an epoxy–acrylate emulsion.…”

“… It is clear from this equation that those factors that can lower the viscosity of the dispersed phase can also serve to reduce the ultimate particle size that can be achieved. In the present study this is achieved by addition of monomer to the oil‐in‐water emulsion containing the dispersed epoxy phase and the polymeric dispersant 1. A smaller particle size reduces the Gibbs free energy of the system and contributes to the ability of the epoxy–acrylate to remain emulsified.…”

“… The concentration of particles in the latex ( N c ) features in both the equations determining the entry rate of radicals as well as the rate of emulsion polymerization. Consequently, those factors that influence particle size will also influence the concentration of particles in this study 1. Equation 4 shows the relationship between the exit rate and the radius of the particle.…”

Factorial experimental design approach in semicontinuous emulsion polymerization of methyl methacrylate to study the effect of process variables

“…The application of statistical design of experiments in emulsion polymerization is reported in the literature, i.e., (i) the Placket‐Burman design was used to investigate the effect of 12 variables in making the core‐shell latexes using 16 experiments,2 (ii) Chern and Hsu studied the effect of various reaction parameters on the particle nucleation and growth in butyl acrylate (BA)/ methyl methacrylate (MMA) copolymers3, (iii) Yang and Yang4 applied statistical experimental strategies in emulsion copolymerization of styrene and n ‐butyl acrylate, (iv) Wen et al5 also used the statistical design strategy to optimize properties in emulsion copolymerization of MMA and acrylonitrile, (v) Rempel et al studied the effect of process variables on the grafting reaction of styrene and MMA onto natural rubber and styrene‐butadiene rubber,6, 7 (vi) use of factorial experiments for improved process understanding in ethylene‐vinyl acetate semibatch emulsion copolymerization was studied by Penlidis and coworkers,8 (vii) Saldivar et al9 studied the effect of initiator, surfactant, water‐to‐monomer ratio, and monomer composition in emulsion copolymerization of acrylic monomer by fractional factorial method, (viii) Wet‐Roos et al10 also studied the influence of salt, initiator, amine, and stirring speed in emulsion polymerization of an epoxy–acrylate emulsion stabilized with polyacrylates. However, no reports are available regarding the synthesis of PMMA latex using factorial design of experiments.…”