抄録
The shear rate-dependent relaxation spectra of polymer melt were experimentally determined by using an improved rotatory viscometer so as to keep a constant shear strain during the relaxation measurement. The maximum relaxation time τM is independent of shear rate in the Newtonian flow region, but it decreases with increasing shear rate in the non-Newtonian flow region. The viscosity calculated as a function of shear rate interpreted satisfactorily the observed viscosity and its dependency of shear rate. The close agreement between the theoretically predicted and observed values of the first normal stress difference was also obtained.
