Convenient post-curing reactions for aqueous-based polyurethane anionomers

Abstract

Anionic aqueous-based polyurethane (PU) dispersions were prepared by introducing carboxylic groups into a conventional PU backbone, followed by a water dispersion process. The resulting carboxylic groups containing aqueous-based PUs were amino-terminated anionomers. Two model reactions between an amino and a carboxylic group containing compounds with an epoxide and an aziridinyl compound, respectively were carried out at ambient temperature. Di-functional epoxide and aziridinyl compound were employed as the convenient single post-curing and dual-curing agents for these prepared PU dispersions. Di-aziridinyl compound was stable in aqueous PU dispersions as a latent curing agent when the pH value of the system was 8.0 or above. The curing behaviors of each PU curing system were monitored by measurements of the gel content, average particle size, zeta potential, and fluorescence spectra. The mechanical and thermal properties of these post-cured PUs were evaluated.