The structure and properties of acrylic-polyurethane hybrid emulsions

Acrylic-polyurethane hybrid emulsions were prepared by converting amphiphil ic acrylic-polyurethane graft copolymers previously synthesized in nonaqueo us media by grafting vinyl monomers to partially vinyl-endblocked polyureth anes to aqueous emulsions. These emulsions were found to form core-shell st ructures in aqueous media using transmission electron microscopy and C-13 N MR measurements in D2O, It was also demonstrated that the hydrophilic compo nent in the amphiphilic acrylic-polyurethane graft copolymers is preferenti ally located in the shell region of the hybrid emulsion particles. The part icle sizes and viscosity of the hybrid emulsions varied depending on the co mposition of hydrophobic and hydrophilic components and the content of carb oxylic groups. Acrylic-polyurethane emulsions in which the shell region is occupied by the acrylic part or polyurethane part were successfully prepare d. The surface properties of the dried clear films formed from acrylic-poly urethane 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 preferentiall y oriented toward the surface layers of the dried films as well as at the i nterface between emulsion films and the plastic films. (C) 2000 Elsevier Sc ience S.A. All rights reserved.