Design carboxymethyl cotton knitted fabrics for wound dressing applications: Solvent effects

Carboxymethyl cotton knitted fabrics (CM-CKFs) for wound dressings were fabricated with different solvents: water, ethanol-water, and isopropanol-water. The FTIR analysis showed that carboxymethylation reaction in the CM-CKFs occurred with the different solvents. With the water, ethanol-water and isopropanol-water order and the decrease of water ratio in the mixed solution, the degree of substitution (DS) increased, the crystallinity index of the CM-CKFs decreased, crystal structure of cellulose changed from type I to II, and appreciable increased in fiber diameter and gel formation. The water absorbency and water retention of the CM-CKFs increased with DS. The water absorbency of the CM-CKFs treated in water, ethanol-water (v/v =3/1), and isopropanol-water (v/v =3/1) was 1.86, 6.95, and 14.86. g/g, respectively. The breaking force of the CM-CKFs was lower than that of cotton knitted fabrics, but the breaking force increased with the DS, so did the breaking elongation. The water vapor permeability and water diffusibility decreased with the DS. The results demonstrated that the carboxymethylation of CM-CKFs occurring in isopropanol-water was most effective and uniform. The findings have theoretical and practical significance for the industrial uses of carboxymethyl cellulose dressing.