Modeling flow-induced crystallization in fiber spinning

A brief review is given of the microstructural/constitutive model for flow- induced crystallization (FIC), developed by the authors that couples polyme r microstructure (molecular orientation and crystallinity) with the macrosc opic velocity/stress and temperature fields. Application of the model to me lt spinning of nylons and poly(ethylene terphthalate) (PET) under both low- and high-speed spinline conditions is described. The fiber spinning model includes the combined effects of FIC, viscoelasticity, filament cooling, ai r drag, inertia, surface tension and gravity, and simulates melt spinning f rom the spinneret down to the take-up roll device (below the freeze point). For both nylons and PET, model fits and predictions are shown to be in ver y good quantitative agreement with spinline data for the fiber velocity, di ameter and temperature fields at both low- and high-speed conditions, and, with flow birefringence data available for high speeds. The model captures the necking phenomenon for nylon and PET quantitatively and the associated extensional softening at high-speed conditions and the occurrence of the fr eeze point naturally at both low- and high-speed conditions. (C) 2001 Elsev ier Science Ltd. All rights reserved.