The use of reactive surfactants is a promising way of avoiding the deleterious effects on film properties caused by the segregation of conventional surfactants. In this work, the distributions of conventional and reactive anionic surfactants in acrylic latex films are compared. Atomic force microscopy was used to examine the surface of the films cast from high solids content acrylic latexes, and Rutherford backscattering spectrometry provided depth profiles of the surfactants. It was proven conclusively that the use of surfmers is an effective way of eliminating unwanted surfactant exudation. The amount of conventional surfactant (sodium lauryl sulfate (SLS)) exuded to the surface increased with the temperature at which the films were annealed (60, 90, and 125 °C), but the migration of the surfmer (sodium tetradecyl maleate) was very minimal and only weakly dependent on temperature. An unexpectedly large amount of conventional surfactant was exuded to the film surface when annealed at 125 °C. This result suggests that its transport to the surface might be facilitated by the enhanced mobility of poly(acrylic acid) shells at temperatures above the polymer's glass transition temperature (ca. 106 °C).

The water sensitivity of films obtained from high solids content acrylic latexes was investigated, with special focus on the role of the surfactant used in the synthesis step. The performance of films obtained from latexes stabilized by nonionic surfmers was compared to that of the acrylic latexes stabilized with conventional nonionic and anionic surfactants. It was seen that the latexes stabilized with reactive surfactants exhibited a remarkably better resistance to both water permeability and water vapor permeability and therefore enlarged the durability of the films. Atomic force microscopy images suggested that the defects created by surfactant migration in the latexes stabilized with conventional surfactants promoted the permeation of water by capillarity.

SYNOPSISThe effect of the monomer/water ratio on the rate of polymerization per polymer particle in both seeded emulsion polymerizations and miniemulsion polymerizations was used in an attempt to elucidate the main locus of radical formation in emulsion polymerization initiated by an oil-soluble initiator ( AIBN) . It was found that, for the rest of conditions constant, the polymerization rate per polymer particle increased when the monomer/water ratio increased, namely when the amount of initiator dissolved in the aqueous phase per polymer particle decreased. This is an evidence against a dominant aqueous phase formation of radicals. On the other hand, these results are consistent with a mechanism in which the radicals are mainly produced in the oil-phase with significant aqueous phase termination.

Waterborne acrylic‐alkyd nanocomposites are expected to combine the positive properties of alkyd resins and acrylic polymers. In this work, the kinetics of the miniemulsion polymerization used to synthesize these nanocomposites and the effect of the process variables on the polymer architecture and particle morphology was investigated. It was found that resin hydrophobicity and the type of initiator strongly affected the microstructure of these materials. The mechanisms responsible for these effects were discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4871–4885, 2009

Waterborne pressure sensitive adhesives with biobased contents up to 72% and adhesive performance comparable to pure oil-based formulations have been developed. For that, partially biobased commercial 2-octyl acrylate and isobornyl methacrylate monomers (derived from castor oil and pine resin, respectively) are copolymerized by emulsion polymerization, an environmentally friendly procedure which allows fine-tuning the microstructure of the copolymer at high solids content as well as notably reducing the VOCs in the final product. Formulations with well balance adhesiveness and cohesiveness are achieved, and the reasons are thoroughly discussed. Furthermore, the moderate reduction of the biocontent by the substitution of part of 2-octyl acrylate by the oil-based 2-ethylhexyl acrylate provides trade off waterborne formulations with very promising adhesive properties.

Hybrid nanoparticles containing proteins have a technological interest because they attempt to achieve improved properties with respect to the single materials by chemically linking both components. In this article, the batch emulsion polymerization of methyl methacrylate in the presence of varied concentration of casein and tert-butyl hydroperoxide as initiator was investigated. A detailed characterization of the molecular microstructure and morphology of the hybrid nanoparticles allowed the identification of two competitive particle formation mechanisms. Compatibilized nanoparticles were produced at the beginning of the polymerization, while uncompatibilized particles could be generated by a second way of nucleation, which is promoted by the ungrafted protein and depends on its concentration.Fil: Picchio, Matías Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Minari, Roque Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Gonzalez, Veronica Doris Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Passeggi, Mario Cesar Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Vega, Jorge Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Barandiaran, María. Universidad del Pais Vasco; EspañaFil: Gugliotta, Luis Marcelino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentin

in Wiley InterScience (www.interscience.wiley.com).The mechanisms involved in the formation of high solids content composite polymer-monomer waterborne miniemulsions in a high-pressure homogenizer were investigated combining experimental results and a mathematical model for the process. It was found that the final droplet size was the result of two consecutive processes: droplet break-up and coagulation. The final droplet size was determined by the mechanism giving the largest droplet size

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