The interior of cotton fibers was lightly modified with monochloroacetic acid and their water absorbency was examined by differential scanning calorimetry. The aim of the selective modification is to prepare the cotton fibers which have high water absorbency and yet maintain their natural handling characteristics and other textile properties. To attain this it was found that the optimal degree of carboxymethylation (DS) is in the region of 0.01 to 0.02.
　The carboxymethylated cotton fibers were transformed into their Na-salt form by alkali-treatment, and their water absorbency was compared with that of the acid form. It was found that ( 1 ) in the case of acid form, the modified fibers absorbed about 120 ~ 130% as much water as the untreated fibers, ( 2 ) the water absorbency of the fibers was further enhanced to two times that of the acid form by transforming carboxyl groups into their Na-salt form, and ( 3 ) the water absorbency of modified cotton fibers having a DS value of 0.02 was much higher than that of amorphous celluloses, indicating that the effect of the cleavage of hydrogen bonds by incorporating substituents, i. e., carboxymethyl groups, on the water absorbency of modified cotton fibers is negligible.

DESCENTE SPORTS SCIENCE Vol.13/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE