DIFFUSION OF ACETIC ACID IN DIRECT WET SPINNING OF TRIACETATE

Abstract

In this report, diffusion of acetic acid, which was the fundamental phenomena in direct wet spinning of triacetate, was investigated.
Spinning dope of triacetate in direct spinning was composed of triacetate, acetic acid (as the solvent), and small quantity of impurities; the dope coagulated easily with the decrease of acetic acid concentration. In triacetate direct spinning, the relation between solvent concentration and coagulation was principal, and this solvent concentration in filaments was determined by diffusion of acetic acid to the spinning bath from the filaments.
In the present study, this diffusion phenomena of acetic acid during the spinning was studiedd quantitatively in connection with various spinning conditions. Furthermore, the effect of diffusionn phenomena on spinnability was studied, and it was recognized that these were closely related.
The diffusion constant of acetic acid in filament during the spinning was approximately 1×10^-6cm²•sec^-1 at 20°C, which was the order of about 1/10 of the diffusion constant in acetic acid aqueous solution. The apparent activation energy was 6.3K cal/mol.