Synthesis and Surface Property of Siloxane-modified Aqueous Polyurethane

A series of novel aqueous emulsion of siloxanemodified polyurethane (PU(PE-PSI)) were synthesized based on poly(propylene glycol) (PPG), polyether-grafted polysiloxane (PEPSI), 2,4-tolylene diisocyanate (TDI), dimethylol propionic acid (DMPA) and 1,4butanediol (BDO) through a direct water emulsification of triethylamine (TEA). The aqueous emulsion was transparent and had a good stability. Fourier transform infrared spectroscopy (FTIR) was used to identify the structure of PU(PEPSI), indicating that the polysiloxane segment had been incorporated with polyurethane chain. Investigation of Electron Spectroscopy for Chemical Analysis (ESCA) and the water contact angle demonstrated that the siloxane migrated to the surface of film. The results also showed that PU(PE-PSI) was still a very good elastomer. With increasing the content of PEPSI, the resistance to water improved and tensile strength increased, while the ultimate elongation decreased slightly for the PU(PE-PSI) film.