Publikace detail

Thickening Effect of Commercial Associative Thickeners on the Latices of Copolymers of Acrylic Monomers Carrying Hydrophilic Reactive Groups

Autoři: Quadrat Otakar | Horský Jiří | Šňupárek Jaromír

Rok: 2003

Druh publikace: článek v odborném periodiku

Název zdroje: Journal of Dispersion Science and Technology

Název nakladatele: Marcel Dekker Inc

Místo vydání: USA

Strana od-do: 179-184

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
cze	Thickening Effect of Commercial Associative Thickeners on the Latices of Copolymers of Acrylic Monomers Carrying Hydrophilic Reactive Groups	Investigation of flow properties of butyl acrylate/styrene/2-hydroxyethyl methacrylate/acrylic acid laties thickened by commercial associative thickeners based on hydrophobic ethoxylated urethane (HEUR) or hydrophobically modified alkali-soluble emulsion (HASE) showed that the apparent viscosity, at a constant medium shear rate, increased with the increasing content of 2-hydroxyethyl methacrylate (HEMA). In contrast, the relative change in latex viscosity after the thickener addition (thickening efficiency), expressed as the ratio of viscosities of the thickened and untreated latices, decreased. This indicates that the increase in viscosity of the thickened latex with a higher HEMA content is caused by the increasing viscosity of the untreated latices due to rising hydrodynamic volume of alkalinized latex particles and not by higher particle bridging with the thickener macromolecules. The HEMA monomer clearly increases hydrohilicity of the particle surface which reduces adsorption of hydrophobic ends of the thickener on latex particles and the thickening efficiency decreases.
eng	Thickening Effect of Commercial Associative Thickeners on the Latices of Copolymers of Acrylic Monomers Carrying Hydrophilic Reactive Groups	Investigation of flow properties of butyl acrylate/styrene/2-hydroxyethyl methacrylate/acrylic acid laties thickened by commercial associative thickeners based on hydrophobic ethoxylated urethane (HEUR) or hydrophobically modified alkali-soluble emulsion (HASE) showed that the apparent viscosity, at a constant medium shear rate, increased with the increasing content of 2-hydroxyethyl methacrylate (HEMA). In contrast, the relative change in latex viscosity after the thickener addition (thickening efficiency), expressed as the ratio of viscosities of the thickened and untreated latices, decreased. This indicates that the increase in viscosity of the thickened latex with a higher HEMA content is caused by the increasing viscosity of the untreated latices due to rising hydrodynamic volume of alkalinized latex particles and not by higher particle bridging with the thickener macromolecules. The HEMA monomer clearly increases hydrohilicity of the particle surface which reduces adsorption of hydrophobic ends of the thickener on latex particles and the thickening efficiency decreases.	latices of acrylic copolymers containing 2-hydroxyethyl methacrylate groups;associative thickeners;thickening efficiency

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