The effects of sodium salts on the additive in viscose regeneration process



Various chemical additives are commonly used in viscose to reduce the swelling of the resultant fibers and films. It was found that inorganic sodium salts, introduced into the additive-containing viscose, alter the action of the additive. The following salts, listed in order of the values of gel swelling ratios obtained with them, interfere with the deswelling of the viscose during regeneration: citrate > thiosulfate > tartrate > sulfate > chloride = phosphate = thiocyanate > acetate > nitrate > control. Sodium idodide did not affect the usual deswelling of the films, and sodium sulfide and sodium carbonate caused the films to deswell slightly more than the control sample. It was proposed that the effectiveness of the salts follows a Hofmeister or lyotropic series.