A comparison of Newtonian and viscoelastic constitutive models for dry spinning of polymer fibers

Abstract

ABSTRACT:A comparison is made of the predictions of one-dimensional mathematical model simulations of dry spinning based on Newtonian and viscoelastic constitutive equations for the spin dope. The viscoelastic model is based upon a modified Giesekus constitutive equation with a temperature and composition-dependent relaxation time. The simulation algorithm includes the effects of the glass transition on the expected solution viscosity and relaxation time behavior along the spinline. Predictions of axial velocity, tensile stress, and composition profiles for the two cases suggest the role of viscoelasticity in the locking-in behavior associated with fiber solidification along the spinline. The effects of model parameters and processing conditions are also discussed.

Two-dimensional modeling of dry spinning of polymer fibers

“…10. After the point of maximum die swell, the total stress increases constantly and around the glass transition point, in the absence of air drag, the stress would lock-in at a constant value, as shown in our previous one-dimensional simulation [8]. In this case, the continued rise in stress after the glass transition point reflects the effect of the air drag.…”

“…As advocated by Schreiber et al [9] and Hayahara and Takao [10] that an elastically deformable entanglement network is formed at a critical solution concentration or molecular weight while preparing the spinning dope, we assume that a similar entanglement network will be formed in the course of dry spinning [8]. Fig.…”

“…For acetone, an h/k y value of 11.6 cal/(g mol K) estimated by Ohzawa and Nagano [3] is used. Estimation of other physical properties and coefficients is shown elsewhere [8], including heat capacity, acetone latent heat and other properties, air drag coefficient, and the quench air properties. Some related properties of pure CA and acetone are given in Table 1 [6].…”

Modeling of solvent evaporation from polymer jets in electrospinning

“…[19][20][21][22][23] For polymer jets in dry fiber spinning, a few studies have been conducted on the steady-state temperature and solvent concentrations in the jets. [24][25][26][27] Recent electrospinning experiments with controlled environmental humidity have demonstrated the importance of solvent evaporation to nanofiber formation. 28 Nevertheless, kinetics of solvent evaporation from electrospun jets has not yet been studied.…”

Proximal Probes Based Nanorobotic Drawing of Polymer Micro/Nanofibers

“…It is expected that the solvent evaporation rate will be an important factor in fiber formation because the solidification that results from solvent evaporation involves irreversible changes in structural and macroscopic characteristics of the material [32]. Evaporation of the solvent from the polymer solution increases the viscosity and the relaxation time and, thus, has a direct effect on the thinning characteristics of the fiber.…”