Solution properties of hexamethylene diisocyanate based polyurethane cationomers

Summary

Viscosity measurements of hexamethylene diisocyanate based cationomer in various polarity solvents and in water/solvent were performed. For the un-ionized sample in pure MEK and DMF, the reduced viscosities of both solutions follow the Huggins relation. For ionized samples in pure MEK and DMF, aggregation of the ionized hard segments still exist in the MEK and DMF solution in the high polymer concentration range, whereas chain expansion occurs in the DMF solution in the low polymer concentration range. For ionized samples in water/solvent mixtures, at a mixing ratio (by weight) of 0.12, the reduced viscosity indicates an aggregation behavior in MEK/water and a polyelectrolyte behavior in DMF/water. At a mixing ratio (by weight) between 0.24 and 4.44, the reduced viscosity indicates a polyelectrolyte behavior. The polymer particles change from a clear elastic gel to microspheres. For emulsions of the ionized samples, the reduced viscosity exhibits polyelectrolyte behavior.