Effect of non-isothermal oriented crystallization an the velocity and elongational viscosity profiles during the melt spinning of high density polyethylene fibers

Based on the experimental data of spine line temperature and percent crysta llization, a time-integral constitutive equation has been used together wit h the degree of phase transformation theory to predict the velocity and elo ngational viscosity profiles. For the velocity profile, our predicted resul ts are compared to experimental data and good agreement is found. Under a d rawing force, the elongational viscosity profile shows a stress softening d ue to the molecular alignment; then the fiber hardens close to the take-up point, owing to filament crystallization.