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Viscoelastic Behaviour of Butyl Acrylate/Styrene/2-Hydroxyethyl Methacrylate/Acrylic Acid Latices Thickened with Associative Thickeners
Authors: Quadrat Otakar | Mikešová Jana | Horský Jiří | Šňupárek Jaromír
Year: 2003
Type of publication: článek v odborném periodiku
Name of source: Comptes Rendus Chimie
Publisher name: Elsevier France
Place: Paris, France
Page from-to: 1411-1416
Titles:
Language Name Abstract Keywords
cze Viscoelastic Behaviour of Butyl Acrylate/Styrene/2-Hydroxyethyl Methacrylate/Acrylic Acid Latices Thickened with Associative Thickeners The rheological behaviour of butyl acrylate/styrene/crylic acid latices thickened with a hydrophobically modified ethoxylated polyurethane (HEUR) or hydrophobically modified alkali-soluble polyacrylate emulsion (HASE) was investigated. While the pseudoplastic character of frequency dependence of complex viscosity was similar for both thickeners, viscoelastic behavuour, expresed as the ratio of loss and storage moduli, significantly different, indicating that the HEUR molecules, unlike swollen HASE particles, create a viscoelastic space structure. The increase in hydrophilicity of the particle surface, achieved by incorporation of 2-hydroxyethyl methacrylate (HEMA) monomer into the latex copolymer reduced the viscoelasticity of latices thickened with HEUR, but not of those thickened with HASE. This confirms that adsoption of hydrophobic end-groups on particle surface is imposrtant for thickening of latices with HEUR and that a physical network of latex particles interconnected by the thickener macromolecules is formed. N
eng Viscoelastic Behaviour of Butyl Acrylate/Styrene/2-Hydroxyethyl Methacrylate/Acrylic Acid Latices Thickened with Associative Thickeners The rheological behaviour of butyl acrylate/styrene/crylic acid latices thickened with a hydrophobically modified ethoxylated polyurethane (HEUR) or hydrophobically modified alkali-soluble polyacrylate emulsion (HASE) was investigated. While the pseudoplastic character of frequency dependence of complex viscosity was similar for both thickeners, viscoelastic behavuour, expresed as the ratio of loss and storage moduli, significantly different, indicating that the HEUR molecules, unlike swollen HASE particles, create a viscoelastic space structure. The increase in hydrophilicity of the particle surface, achieved by incorporation of 2-hydroxyethyl methacrylate (HEMA) monomer into the latex copolymer reduced the viscoelasticity of latices thickened with HEUR, but not of those thickened with HASE. This confirms that adsoption of hydrophobic end-groups on particle surface is imposrtant for thickening of latices with HEUR and that a physical network of latex particles interconnected by the thickener macromolecules is formed. dispersions; adsorption; rheology; latex; polymers