Effect of fiber structure on heat of wetting of cotton and regenerated cellulosic fibers

A new calorimeter is constructed to precisely measure the heat of wetting o f cotton, regular viscose rayon, high wet strength viscose rayon, and Tence l(R). Our purpose is to investigate the relationship between the heat of we tting and structural characteristics of fibers such as crystal and fiber st ructure, degree of crystallinity, and water absorbency properties (water re gain, moisture regain, and bound water content of fibers). Despite its rela tively high water regain, cotton has the lowest heat of wetting among the f ibers studied so far. The heat of wetting of cellulosic fibers depends slig htly on fiber and crystal structure but decreases proportionally with the i ncreasing degree of crystallinity of the fibers. The heat of wetting is clo sely related to the amount of bound water estimated by differential scannin g calorimetry. These results are discussed from the viewpoint of designing high performance cellulose materials.