Polyurethane ionomers.part ii.preparation,structure,properties and applications of polyurethane cationic dispersions

摘要

Urethane-isocyanate prepolymers have been synthesized in reactions of 1,4- or 2,6-tolylene diisocyanate(TDI)with various polyols.Then tertiary N-alkyl groups were introduced into prepolymers,in reaction with N-butyl- or N-methyldiethaneamine,and the products were protonated with HCOOH to obtain polyurethane cationomers with ammonia groups.Selected cationomer underwent reaction with 2-hydroxyethyl aerylate(HEA)to appropriate macrocationomer(Table 1).~1H NMR and IR spectra presented(Figs.1-4,Table 2)confirm the expected structures of selected cationomer as well as of macrocationomer.Significant polydispersity of the products has been found using GPC measurements(Fig.5,Table 3)what was interpreted as coming from the process of synthesis of several stages.Particle size distributions of aqueous dispersions obtained were determined(Fig.6,Table 4).Contact angle values have been determined as well.Hardness(Fig.7)and abrasion(Fig.8)of the coatings,obtained from the dispersions prepared,were determined.On this basis the dispersion of macrocationomer prepared from TDI,oligo(oxyethylenecaprolactono)diol and HEA has been chosen as optimal system suitable for water-soluble varnishes'preparation.