Preparation of aqueous dispersible polyurethane: Effect of acetone on the particle size and storage stability of polyurethane emulsion

Abstract

An aqueous dispersible polyurethane was prepared by the reaction of hydroxyl-terminated poly(ethylene adipate), dimethylol propionic acid, 4,4Ј-diphenylmethane diisocyanate, and ethylene glycol. Formation of the dispersion was achieved by phase inversion of an acetone solution of the polyurethane with water, utilizing carboxylate anion groups as the internal emulsifying sites. The amount of acetone added has a large effect on the particle diameter (0.08 to 8.61 m) and particle size distribution of the polyurethane emulsion. The storage stability was evaluated in terms of particle size distribution breadth. The aqueous emulsion obtained with no use of acetone was sufficiently stable in storage for at least 6 months. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: [3455][3456][3457][3458][3459][3460][3461] 2004

The influence of the ionic concentration, concentration of the polymer, degree of neutralization and chain extension on aqueous polyurethane dispersions prepared by the acetone process

“…Despite this advantage there are very few Refs. [35][36][37][38][39][40] related to this process in the open literature. Within these detailed investigations a modified acetone process was used in which acetone replaced some, but not all, of the NMP in the PU dispersion.…”

Effect of added amines on the morphology of multivesiculated polyester particles

“…Some of the polyester chain ends, on the other hand, are positioned at the external surface of the organic droplet. A dense solvation layer surrounds the hydrophilic ion‐pairs, creating an oil‐in‐water stabilization mechanism similar to the one observed in aqueous polyurethane dispersions (PUDs) containing neutralized pendant carboxylic groups . We therefore hypothesize that the neutralized carboxylic groups can contribute both to the water‐in‐oil (W/O) stabilization of the inner vesicles and to the oil‐in‐water (O/W) stabilization of the organic droplets.…”

Metal Catalysis inside Polymer Frameworks: Evaluation of Catalyst Stability and Reusability

“…Basically, polyurethane oligomers containing polar groups are prepared by polycondensation in acetone, before pouring the mixture into excess water. In most of the articles published in this field, including some recent references,55, 56 the emulsification was probably not caused by the Ouzo effect, in view of the high polymer concentration in the acetone (30–70 wt %) prior to emulsification. Instead, we suppose that these emulsifications proceed by spinodal decomposition, which explains why larger particles are obtained when acetone is used than those obtained in the absence of a solvent.…”