Comparing and contrasting the properties of urethane/acrylic hybrids with those of corresponding blends of urethane dispersions and acrylic emulsions

The mechanical properties of the dry films were measured by tensile testing. The hybrids were found to compare favorably with, and in some areas exceed, the PUD alone in tensile performance. In contrast the performance of all of the blend systems fell short of the PUD and of the corresponding hybrids. Within the set of blends the best tensile results were achieved using the low Tg, high molecular weight acrylic emulsions. There were no clear trends with changes in acrylic emulsion particle size or acid content. The difference in performance between blends and hybrids is attributed to the increased phase mixing and the improved dispersion of phase domains in the hybrids.