Industrial & Engineering Chemistry Research, Vol.54, No.9, 2447-2452, 2015
Partitioning of 2-Carboxyethyl Acrylate between Water and Vinyl Monomer Phases Applied to Emulsion Polymerization: Comparisons with Hydroxy Acrylate and Other Vinyl Acid Functional Monomers
In an extension of our recent studies on the distribution of vinyl acid (AA and MAA) and hydroxy (meth)acrylate monomers in emulsion polymerization systems, we report the distribution behavior of 2-carboxyethyl acrylate (CEA) between water and various nonfunctional monomers. Similar to that previously reported for AA and MAA, the distribution of CEA strongly depends upon the hydrogen-bond-acceptor characteristics of the nonfunctional monomer organic phase. The logarithm of the distribution coefficients for CEA correlate linearly with the molar volume of (meth)acrylate monomers. The CEA molecule is a replica of 2-hydroxyethyl acrylate (HEA) with a different functional group. Evaluation of the distribution behaviors of CEA and HEA allows for a direct comparison of the carboxyl and hydroxyl moieties in determining the distributions. The strong dipole moment of the hydroxy group makes HEA significantly more polar than CEA. Also, comparisons of the distribution behaviors of CEA with those for AA and MAA allow us to understand the combined effect of the ester and carboxylic acid groups in CEA on the overall polarity of these vinyl acid monomers and their distribution behaviors.