Polycondensation of carboxylic acids and carbinols in aqueous emulsion

Water-insoluble diols and dicarboxylic acids condense to polyesters in aqueous emulsion under relatively mild conditions in the presence of sulfonic acids. Azelaic acid and 1,10-decanediol give conversions to polymer of 50% and 75%. Molecular weights range between 1500 and 3000. The best catalysts are sulfuric acid or the sulfonic acid surfactants. Water soluble monomers give little or no increase in molecular weight. Estimates based on equilibrium constants for a typical esterification, and the observed molecular weights indicate that only minute amounts of water can be present at the site of reaction. It is suggested that the process might be related at least in some aspects to the condensation polymerization of silanol-ended polydimethylsiloxane oligomers in emulsion [1].