The rheological behavior of HIPS prepolymers with rubber having different molecular weights were studied. It was found that

besides the phase inversion point

there existed another minimum on the apparent visco-sity-versus-conversion curve at about 7% conversion. The rheological characteristics of the prepolymers were also affected by agitation speed

viz

the higher the speed

the lower the apparent viscosity of the prepolymer obtained. These phenomena were explained in terms of the two-phase characteristics of the prepolymer. Furthermore

the temperature effect on the prepolymer Theological behavior was investigated

and the apparent visco-sity(ηa)can be correlated with temperature(T)and shear rate(γ)by where A1

A2

B1 and B2 are regression coefficients.