Synthesis of Hydrophobically modified ethoxylated non-isocyanate urethanes (HENIURs) and their use as rheology additives
Résumé
Telechelic associative polymers such as Hydrophobically modified ethoxylated urethanes (HEURs) are an important class of rheology additives used in many industrial fields allowing a precise control of the rheology. To avoid the use of toxic isocyanates, more eco-friendly HEURs were synthesized based on the cyclo-carbonate/amine addition reaction. Hydrophobically modified ethoxylated hydroxyurethanes (HEHURs) were thus obtained by the aminolysis of telechelic 5-membered cyclic carbonates functionalized PEG in the presence of hydrophobic amines of 14, 16 and 18 carbons. The rheological properties (G', G'' and η*) of these amphiphilic structures were investigated, as well as the influence of different parameters such as: temperature (5 to 25 °C), concentration (10 to 20 wt%) and hydrophobic chain length. Their rheological properties were also compared to isocyanate-based equivalent structures (HEURs). Finally, HEHURs were used in latex solution to illustrate their potential use as rheology additives and their thickening efficiency at 0.25 wt%. Mainly Newtonian to fully pseudoplastic profiles were obtained depending on the variation of the hydrophobic chain length.
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