Frequency response analysis of polymer melt spinning

The dynamics of a viscoelastic polymer melt spinline are analyzed by solving the linearized perturbation equations in the frequency domain using a realistic constitutive equation for the melt rheology. The computed frequency response is in reasonably good agreement with experiments on the spinning of poly(ethylene terephthalate), but the agreement is poor for polypropylene, which is highly elastic and very shear-thinning. The implication is that a better understanding is needed of the process of solidification under stress, which is the major omission in the spinline model