Modification of Acrylic Emulsion Polymers with Vinyl Neo-Esters
Enhancing Performance and Providing a Route to Cost-Efficient Alternatives
In the 1950s, Dr. Herbert Koch from the Max Plank Institute in Mülheim, Germany, found that olefins may react with carbon monoxide and water under the influence of strong acids to form tertiary branched neocarboxylic acids (Figure 1). Before the intermediate carbocation reacts with carbon monoxide, isomerization reactions are observed and, therefore, the resulting acid is composed of a number of isomers.1,2
The neocarboxylic acid can be converted into its vinyl ester monomer by reaction with acetylene. Vinyl neo-esters are very hydrophobic monomers with a highly branched tertiary substituted a-carbon structure. Their principal use is as hydrophobic co-monomers in vinyl and acrylic polymerization. The alkyl neocarboxylic group of these monomers is very resistant to degradation in alkaline conditions, as there is no hydrogen on the a-carbon atom. The branched tertiary structure with bulky and hydrophobic hydrocarbon groups provides neo-ester monomers (Figure 2) with a highly hydrophobic nature and low surface tension. Furthermore, these vinyl neo-esters exhibit strong resistance to hydrolysis and do not degrade under the influence of UV light.