Hybrid and blend systems compared

Study compares properties of PU/AC hybrid and blend systems Source: Wolsczak - Fotolia.com

Brazilian and Argentinean researchers compared in their new study properties of hybrid and blend systems. They prepared polyurethane-acrylate hybrid composites (with 10, 30, 50, 70 and 90 wt % of acrylic content) by emulsion polymerization of acrylic monomers. Blends with the same acrylic content were also obtained by mixing polyurethane and acrylic dispersions. Mechanical properties, Buccholz and pencil hardness, surface roughness and water contact angle of films were determined. The effect of the acrylic content on morphology and film properties was also evaluated. The properties of hybrid films show a non-linear behavior with the increase of the acrylic component, while physical blends exhibit a gradual behavior from PU to AC. The results indicate better acrylicpolyurethane compatibility in hybrid systems than in physical blends. Hybrid composites with up to 70 wt % of acrylic component are homogeneous. On the other hand, blends are phase segregated systems at all composition levels. The study appeared in the November-Issue of "Progress in Organic Coatings", pp. 429-437.