Water, Moisture, and Ash Content of Mechanically-Cleaned Greige Cotton, Naturally-Colored Brown Cotton, Flax, and Rayon

This exploratory research evaluated the Karl Fischer Titration (KFT) reference method (ASTM D7785) to accurately measure water content of mechanically-cleaned greige cotton, a naturally-colored brown cotton, flax, and rayon at moisture equilibrium. Each sample was analyzed by KFT, standard oven drying in ambient air, and isothermal thermogravimetric analysis (TGA) using dry air and nitrogen carrier gases. Water content, as measured by KFT, was (%): mechanically-cleaned greige cotton, 6.82, brown cotton, 7.88, flax, 8.72, and rayon, 11.74. There was a significant difference between water and moisture contents by standard oven drying. Similar differences were observed between TGA in air and nitrogen and varied with ash content. The findings support the use of KFT to determine water content of these diverse cellulosic textile fibers.