The extent and rate of reaction between cotton yarn before and after slack mercerization and slack mercerization followed by stretching and formaldehyde, in the presence of various amounts of sulfuric acid (5-60% by weight) were studied. Beyond a concentration of 45% sulfuric acid, the reaction takes place very rapidly, and an explanation is put forward in terms of the extent of swelling of the fiber in sulfuric acid solutions. The reaction was also studied in the presence of glycerin, when the combined formaldehyde value is shown to decrease with an increasing concentration of glycerin
