Abstract
Abstract
Polyurethane dispersions were prepared and urethane/acrylic composite latices were synthesized with polyurethane dispersions as the seed, and core‐shell emulsion polymerization. Fourier‐transform infrared spectroscopy coupled with attenuated total reflectance (FTIR‐ATR) analyses showed that the films obtained from the composite latices were rich in polyurethane component or segments at air‐facing and substrate‐facing surfaces, in comparison with their average composition. Moreover, the substrate‐facing surface contained even more polyurethane component or segments than the air‐facing surface. X‐ray photoelectron spectroscopy (XPS) detection also indicated that the polyurethane component or segments preferentially migrated to the surface layer of the films from the bulk, and that the films from blend latices displayed more polyurethane component or segments near the surface layer. Both FTIR‐ATR and XPS analyses suggested that some reorientation had happened in synthesizing the composite latices and/or after film formation. This structure and composition endow urethane/acrylic composite films with both surface properties (such as mar‐resistance, adhesion, wettability) from pure polyurethane, and film hardness from acrylic copolymers.
© 2001 Society of Chemical Industry