Calculation of Grafting and Property Characterization in Polyurethane-Acrylic Hybrid Materials Prepared by Emulsion Process

Polyurethane‐acrylics (PU‐AC) hybrid latexes were prepared using isophorone diisocyanate and polypropylene oxides as main monomers for the PU component, butyl acrylate and methyl methacrylate as AC monomers, and hydroxyethyl acrylate (HEA) as coupling agent to build up chemical bonds between PU prepolymers and AC polymers (PAC). A simple method to determine the PU grafted to PAC chains at one end and at both ends was established, which showed that PU grafted to PAC at both terminals was obviously increasing with HEA, and soon became predominant over that grafted by one end when the HEA/NCO molar ratio reached 0.67. With HEA/NCO 1, these properties remained relatively stable. A simple method to determine grafted polyurethanes, PU, to acrylic polymers, PAC, at one end and at both ends was established in hybrid latexes of PU‐PAC prepared with a coupling agent, which shows PU grafted at both terminals was rapidly increasing with more coupling agent as shown in the figure. Several sets of latexes were prepared, and their properties tested. Results were interpreted based on the theoretical method for calculation of PU grafting to PAC.