An Overview of Molten Polymer Drawing Instabilities

Drawing instabilities and rupture are a serious limitation in polymer fiber and film processing. Onset of these defects depends on the processing conditions, on heat transfer, and on the rheology of the polymer even if some may be encountered for Newtonian fluids. The main part of this chapter is devoted to the different forms of the draw resonance instability encountered in fiber spinning, cast film, and film blowing. The time-dependent equations are presented for the simplified situation of constant width cast film. Results of the two possible modeling strategies, linear stability analysis and direct simulation, applied to the different fiber and film processes are discussed.