Modification of aqueous polyurethanes by forming latex interpenetrating polymer networks with polystyrene

A series of latex particles with interpenetrating polymer network structure have been synthesized from waterborne polyurethane (PU) and polystyrene (P S). The effect of PU/PS composition, crosslinking density in the PS domain as well as in PU have been studied in terms of dispersion size, transmissio n electron microscopy morphology, mechanical and dynamic mechanical propert ies in addition to swellability in water and toluene of the dispersion cast film. It was found that inverted core (PS)-shell (PU) morphology was well defined and that the domain size as well as the film properties were well c ontrolled by the latex composition and crosslinking density of both phases.