Synthsis and properties of polyvinyl acetate emulsion copolymers by three novel non-ionic functional polyurethane surfactants

摘要

Functional polyurethane surfactants (tri-block) were synthesized by addition polymerization of hexame-thylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and 2, 4-toluene diisocyanate (TDI) with poly (propylene oxide) (PPO) and monoallyl-end-capped poly (ethylene oxide) (PEO). The chemical structure of the polyurethane surfactants (PUS) was confirmed by Fourier transform infrared, ~1H NMR and ~(13)C NMR spectroscopy. Then, a series of polyvinyl acetate (PVAc) latexes were successfully synthesized by the emulsion copolymerization in the presence of different PUS. The particle size, amount of coagulum and surface tension were evaluated. These polymeric surfactants were found to have excellent surface activity. The lowest surface tension of polyurethane surfactant aqueous solutions could be reduced to 41.5 dyn/cm for IPDI. All the polyurethane surfactants synthesized had low critical micelle concentrations and could reduce the surface tension even at very low concentration levels (10~3-10~2 molL~1).