In the case of the spinning in concentrated sulphuric acid, the viscose pressed out from the cap coagulates and regenerates at once and at the proper concentration, ca. 55% in this experiment, the cellulose swells, gelatinises and has proper plasticity to be stretched but in the higher concentration it has a tendency to disperse into the bath. As to the plastic state of the filaments, the opinions of Dr. Roos or others who explain that the plasticity is due to cellulose xanthate and not regenerated cellulose are not secured to be the fact in this experiment at least. And it is thought that the stretch-spinning due to this plasticity is practically not so easy to be carried out under optimum conditions as Lilienfeld claims.
View full abstract