The synthesis, characterization, and evaluation of model hydrophobe-modified, ethoxylated urethanes.

摘要

Initial investigations were undertaken to define reaction conditions by which Hydrophobe-modified Ethoxylated URethanes (HEUR) could be reproducibly synthesized. Characterization techniques demonstrated that the aqueous solution behavior of HEUR thickeners is a function of the molecular weight distribution and terminal hydrophobe size. Techniques to study the interactions of HEURs with aqueous dispersed phases are also detailed.;In the synthesis and characterization of step growth HEURs (Chapter 2), the size of the terminal hydrophobe was demonstrated to be the combination of the alkyl amine and the diisocyanate used to couple the alkyl amine to the poly(oxyethylene) backbone. Greater viscosity increases could be realized and aqueous solutions became more elastic in their viscoelastic response when the size of the terminal hydrophobe was increased (Chapter 3). The presence of internal hydrophobic groups did not influence rheological behavior. A comparison of a series of HEURs with broad and narrow molecular weight distributions (Chapter 4) demonstrated that the narrow distribution HEURs were more efficient rheology modifiers, but the viscoelastic responses were similar.;A novel Size Exclusion Chromatography technique was developed (Chapter 5) to analyze competitive adsorptions of HEURs and nonionic surfactants on aqueous dispersed TiO;The interaction of HEUR thickener with waterborne polyurethanes was studied with rheological methods (Chapter 6). Decreasing the particle size of the waterborne polyurethane or increasing the size of the terminal hydrophobe increased the viscosity of HEUR-thickened dispersions.;In a series of HEURs with a narrow polydispersity (Chapter 1), the extent of hydrophobe modification was estimated, using H