Hydrophobic, Water-Dispersible Polyurethane: Role of Polybutadiene Diol Structure

Abstract

Preparation of stable, free-standing elastic film with hydrophobic surface from water-dispersible polyurethanes (WDPUs) is a challenging task. Here, we have prepared WDPUs from polybutadiene-based diols and the resulting PU films are satisfying the requisites. Two types of diols, namely, hydroxyl-terminated polybutadiene (HTPB) and terminal-functionalized HTPB with dinitrobenzene (DNB) [HTPB-DNB], were used to make WDPUs and the effects of diol structures were investigated. The synthesized WDPUs displayed particle morphology with size in the range of ∼130-270 nm and more than 1 year storage stability. WDPUs yielded stable and free-standing films upon curing and the resulting films showed high thermal and mechanical stabilities. The contact angle of the films is in the range of ∼80-100°, attributing the hydrophobic nature of the surface. Hard segment content of the PU varied from 30 to 40% (by weight) to tune the properties of WDPUs and the resulting films.