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

Abstract

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 a,x-polydimethylsiloxanediol (PDMS). 2,2-bis(hydroxymethyl)propionic acid (DMPA) was used as ionic center. The anionomers were extended with ethylenediamine (EDA) in water.1 H NMR and IR methods were employed to confirm the chemical structures of the anionomers. Suitable defined structural factors j and a 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.

Surface free energy of polyurethane coatings with improved hydrophobicity

“…Non-metallic mineral particles (CaCO 3 , TiO 2 and loess) can be incorporated into waterborne polyurethane acrylate to improve surface properties of eco-friendly floor tiles [6]. And on the contrary, the addition of hydroxy-terminated polydimethylsiloxane into soft segments of UV-curable polycarbonate-based polyurethane acrylate dispersions is responsible for inferior polarity and it leads to weaker wettability of coatings [7, 8]. …”