Analytical Investigations on Acrylic Polyurethane Hybrid-Dispersions

By H. Kagerer, H.-U. Moritz, H.-P. Rink, W.A. Jung

Water-dispersible polyurethane acrylic graft copolymers are an important class of hybrid polymers for use as resins in waterborne coatings. In order to study fundamental properties of such polymers, a model system of four polyurethane macromonomers that differ in the average number of double bonds per molecule was developed.

Free radical copolymerization of the polyurethane macromonomers with acrylates was carried out in aqueous phase using the polyurethanes as the re-active emulsifier. The stability of the product dispersions depends on the average number of double bonds per macromolecule and the weight ratio of hydrophilic polyurethane to the acrylic part.

The content of the polyurethane double bonds and their conversion was measured by nuclear magnetic resonance (NMR) spectroscopy and by a titrimetrical method.