The structure and properties of acrylic-polyurethane hybrid emulsions

Acrylic-polyurethane hybrid emulsions were prepared by converting amphiphilic acrylic-polyurethane graft copolymers previously synthesized in nonaqueous media by grafting vinyl monomers to partially vinyl-endblocked polyurethanes to aqueous emulsions. These emulsions were found to form core-shell structures in aqueous media using transmission electron microscopy and C-13 NMR measurements in D2O, It was also demonstrated that the hydrophilic component in the amphiphilic acrylic-polyurethane graft copolymers is preferentially located in the shell region of the hybrid emulsion particles. The particle sizes and viscosity of the hybrid emulsions varied depending on the composition of hydrophobic and hydrophilic components and the content of carboxylic groups. Acrylic-polyurethane emulsions in which the shell region is occupied by the acrylic part or polyurethane part were successfully prepared. The surface properties of the dried clear films formed from acrylic-polyurethane hybrid emulsions were studied by ESCA, contact angle measurements, and adhesion properties to various plastic films were also studied. These results showed that the shell part of the hybrid emulsions is preferentially oriented toward the surface layers of the dried films as well as at the interface between emulsion films and the plastic films. (C) 2000 Elsevier Science S.A. All rights reserved.