Waterborne polyurethane/acrylate: Comparison of hybrid and blend systems

• Published in: Progress in organic coatings Vol. 72; no. 3; pp. 429 - 437
• Main Authors: Peruzzo, Pablo J., Anbinder, Pablo S., Pardini, Oscar R., Vega, Jorge, Costa, Carlos A., Galembeck, Fernando, Amalvy, Javier I.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2011
• Subjects: Acrylates; Atomic force microscopy; Blend systems; Blends; Core–shell morphology; Hybrid composites; Hybrid polymers; Morphology; Polymerization; Polyurethane resins; Polyurethane/acrylate dispersions; SAXS; Blend systems; Hybrid polymers; Polyurethane/acrylate dispersions; Core–shell morphology
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2011.05.016

► Polyurethane–acrylics hybrid and blends. ► Comparison of properties. ► Hybrid systems have core–shell structure. ► Non-linear behavior is observed. ► Hybrids are useful for high performance coatings. Polyurethane/acrylate hybrid composites in a broad range of composition (10, 30, 50, 70 and 90 wt.% of acrylic content), were obtained by emulsion polymerization of acrylic monomers (methyl methacrylate/ n-butyl acrylate/acrylic acid mixture) in the presence of preformed polyurethane chains with polymerizable terminal vinyl groups. Blends with the same acrylic content were also prepared by mixing polyurethane and acrylic dispersions. Samples were characterized by SEC, DLS, FTIR, UV, TEM, AFM, SAXS/WAXS and gel fraction content. Mechanical properties, Buccholz and pencil hardness, surface roughness and water contact angle of films were also determined. The effect of the acrylic content on morphology and film properties was also evaluated. Hybrids are crosslinked systems showing changes in the particle and film morphologies with increasing acrylic content. 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. FTIR results indicate better acrylic–polyurethane compatibility in hybrid systems than in physical blends. Hybrid composites with up to 70 wt.% of acrylic component are homogeneous by SAXS. On the other hand, AFM results show that blends are phase segregated systems at all composition levels.