Waterborne anionomeric polyurethane–ureas from functionalized fluoropolyethers

A family of anionomeric segmented polyurethane–ureas made from α‐ω dimethylol‐terminated perfluoropolyethers (M_n = 1000–2000), isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine was obtained in form of stable aqueous dispersions. The dispersions were characterized by viscometry and dynamic laser light scattering. The main compositive parameters explored were the amount of COOH groups and the length of the fluorinated macromer. The new polyurethane–ureas were characterized by dynamic mechanical analysis obtaining information on modulus, thermal transition, and phase segregation. Surface properties and chemical resistance were estimated through measurements of static contact angles and spot tests with different solvents. Although surface hydrophobicity was not affected by composition, water‐sorption behavior was sensitive to the ionic character (COOH level) of the polymer. Diffusion and permeability coefficients of polymer films, having different carboxyl contents, were estimated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 136–144, 2004     

Convenient post-curing reactions for aqueous-based polyurethane anionomers

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.     

Chemical structure,thermal properties,and free‐surface energy parameters of coatings synthesized from poly(urethane‐dimethylsiloxane) anionomers

Poly(urethane‐dimethylsiloxane) (PU‐PDMS) anionomers with increased hydrophobicity and fixed amount of elastic segments (51 wt %) at 3‐ and 4‐stage methods were obtained. The anionomers were synthesized from isophorone diisocyanate, poly(oxytetramethylene)diol, and α,ω‐polydimethylsiloxanediol (PDMS). 2,2‐bis(hydroxymethyl)propionic acid (DMPA) was used as ionic center. The anionomers were extended with ethylenediamine (EDA) in water. ¹H NMR and IR methods were employed to confirm the chemical structures of the anionomers. Suitable defined structural factors κ and α were calculated on the basis of selected bands of the spectra. The factors were employed to perform detailed quantity and polarity analysis of the anionomers structures. The free‐surface energy (FSE) of the anionomers was evaluated on the basis of physical model by Owens and Wendt. The effect of chemical structures on polarity of the materials was discussed. It was found that the FSE and its polar and dispersive components distinctly decrease with the increasing polisiloxane content in the anionomer chain. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008