New Sizing Agents and Flocculants Derived From Chitosan

Approaches for development of novel textile sizing agents and flocculants based on acid‐hydrolyzed and carboxymethylated chitosans were undertaken. Factors affecting both hydrolysis and carboxymethylation were investigated. Aqueous solutions of hydrolyzed chitosans or carboxymethyl chitosans were applied to light cotton to test the feasibility of such water‐soluble chitosans for textile sizing. The size add‐on on the light fabric is directly related to the concentration of the hydrolyzed or carboxymethyl chitosan in the sizing solution and so does the apparent viscosity of the latter. Hundred percent size removal could be achieved with the hydrolyzed chitosans. A different situation was encountered with carboxymethyl chitosan where the percent size removal increases from 81% to 95% by increasing its concentration in the sizing solution from 5% to 15%. The tensile strength of the sized fabrics increased by about 55% and the elongation at break decreased on average by about 3%. The suitability of the hydrolyzed chitosans and carboxymethyl chitosans as flocculants was also investigated. The degree of flocculation was followed at different pHs by determination of the transmission%. Efficiency of flocculation at pH 6 was greater than at pH 8.