Emulsion polymerization: From fundamental mechanisms to process developments

Abstract

Emulsion polymers are "products by process" whose main properties are determined during polymerization. In this scenario of margins reduction, increasing competition, and public sensitivity to environmental issues, the challenge is to achieve an efficient production of high-quality materials in a consistent, safe, and environmentally friendly way. This highlight reviews the investigations carried out at The University of the Basque Country to develop a knowledge-based strategy to achieve these goals. First, the research in fundamental mechanisms is discussed. This includes studies in radical entry and exit, oil-soluble initiators, propagationrate constants of acrylic monomers, processes involved in the formation of branched and crosslinked polymers, microstructure modification by postreaction operations, the formation of particle morphology, and reactive surfactants. The advanced mathematical models developed in the group are also reviewed. In the second part, the advances in process development (optimization, online monitoring and control, monomer removal, production of high-solids, low-viscosity latices, and process intensification) are presented.

Emulsion copolymerization of styrene and butyl acrylate in the presence of a chain transfer agent.

“…The later models developed have different degrees of complexity (Alhamad et al (2005); Dube and Penlidis (1996); Ginsburger et al (2003), Hoppe et al (2005)), depending upon their scope and application. The most representative have been reviewed by Asua (2004); Chern (2006); Dube et al (1997); Gao and Penlidis (2002) and Thickett and Gilbert (2007).…”

Analysis of optimal operation of a fed-batch emulsion copolymerization reactor used for production of particles with core–shell morphology

“…There is a rich literature on modeling of emulsion polymerization processes, starting with the conventional Smith-Ewart model [2], which identifies three stages in emulsion polymerization process (nucleation, particles growth, and end of polymerization). The later models developed for emulsion polymerization have different degrees of complexity [3,4], depending upon their scope and application. The most representative ones are reviewed by Gao and Penlidis [5] and Chern [6].…”

Synthesis and Optimization of Emulsion Polymers

“…Examples include imidazoline carboxylates and amine oxides. 5,6,7,8 Unlike the other three, non-ionic surfactants do not dissociate in solution to yield a charge. Instead, the hydrophilic part is a non-ionic component such as a polyol, sugar derivative, or chain of ethylene oxide.…”

“…Examples include polyoxyethylenated alklyphenols, polyoxyethylenated straight-chain alcohols, and long-chain carboxylic acid esters. 5,6,7,8 1.…”

“…Anionic and nonionic surfactants are most commonly used in emulsion polymerization due to their higher compatibility with negatively charged latex particles. 5,6,7,8 Anionic surfactants ionize to produce a negative charge on the molecule's polar head. Sodium dodecyl sulfate (SDS), is one of the most commonly used anionic surfactants in emulsion polymerization.…”