Bisphenol A epoxy resin was emulsified to be waterborne system by incomplete phase inversion technique at low concentration of the emulsifier (233wt%)

and both stress sweep and dynamic frequency sweep tests were performed to characterize the rheological behavior of the system during phase inversion evolution.It is shown that the system is a Newtonian fluid with an almost constant viscosity independent on stress before the phase inversion point.At the phase inversion point

the viscosity of the system at low stress increases slightly and the dynamic rheological parameters(storage modulus

loss modulus and complex viscosity) reach their minimum values.After the phase inversion point

the dynamic rheological parameters increase greatly with adding water.It is suggested that the lubrication of water phase among the waterborne particles cominates at the phase inversion point

and phase inversion progress still continues with adding more water.