Drying Behavior of Acetate Filament in Dry Spinning

Abstract

Drying behavior of acetate filament in dry spinning is investigated, including the elongational deformation of polymer solution thread in the early stage of drying. Variations of diameter, velocity, temperature, solvent concentration profile in the thread and tension distribution along the threadline in the spinning column, are calculated for spinning conditions encountered commercially by means of the equations of simultaneous momentum, heat and mass transfer between the thread and hot air flow in the spinning column. Concentration and temperature dependencies of the mutual diffusion coefficient from desorption experiment are correlated by the free volume theory. The elongational viscosity is estimated from the shear viscosity data using Krevelen theory. Residual acetone concentration in the thread and tension at the exit of the spinning column are compared between the calculated results and the experimental data by a commercial apparatus; satisfactory agreement is found. Rapid decreases 1335 ORDER REPRINTS SANOof temperature and surface concentration of the dope thread after extrusion confine the elongational deformation within several centimeters below the spinnerette. Initial elongational rate and die swell ratio are related to the winding velocity and tension at the exit of the spinning column. The tension is determined mainly by initial viscous force and air drag.

Two-dimensional modeling of dry spinning of polymer fibers

“…These are summarized in Table 2. Processing parameters are from [6] and the die swell ratio dsr = 1.6 is an observed value [6]. The mobility parameter, α, and the number of statistical links per segment at the point of maximum die swell, N 0 , can be obtained from fits of the shear rate dependence of the solution viscosity and first normal stress, or from fits of the extensional viscosity [20].…”

“…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].…”

“…Later, Brazinsky et al [5] performed a simple two-dimensional modeling study on both mass and heat transfer processes, in which constant filament density was assumed. More recently, Sano [6] presented a model which is two-dimensional for the mass transfer process only, but includes the affects of variable filament density. In all of these endeavors, a purely viscous, Newtonian constitutive equation was used to model the rheological behavior of the polymer spin solution.…”

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.…”

Study on the Viscoelastic Fluid Behavior in Hollow Fiber Membrane Fabrication Process Using Giesekus’ Model

“…The resulted theoretical analysis was known as Thin Filament Analysis (TFA) based on the assumption of a high-aspect ratio of the ber. Sano [11] and Guo and McHugh [12] coupled TFA with 2D mass transfer analysis and obtained concentration pro les at radial direction. They also provided a reference point for comparison and validation of the techniques developed as a part of the dissertation performed by Didari [13].…”