Effect of chain length of the alkyl in quaternary ammonium substituents on the adhesion-to-fiber, aerobic biodegradation, and desizability of quaternized cornstarch

Commercial native cornstarch was subjected first to acid hydrolysis using HCl and then to cationization using N-(3-chloro-2-hydroxypropyl) trialkylammonium chloride (CHPTAA) to introduce quaternary ammonium substituents onto starch chains with a series of degrees of substitution (DS). Afterward, the effect of chain length of the alkyl in cationic substituents on the quaternization, aqueous paste viscosity, adhesion-to-fiber, aerobic biodegradation, and desizability of starches was investigated for warp sizing. The number of carbon atoms of alkyl in CHPTAA was 1, 2, and 3, corresponding to the introduction of 3-(trimethylammonium chloride)-2-hydroxypropyl (TMACHP), 3-(triethylammonium chloride)-2-hydroxypropyl (TEACHP), and 3-(tripropylammonium chloride)-2-hydroxypropyl (TPACHP) substituents onto starch chains, respectively. The level of starch quaternization was examined in the range of 0-0.06 in DS value. Experimental results demonstrated that the chain length displayed significant effects on the quaternization, paste viscosity, adhesion-to-fiber, aerobic biodegradation, and desizability. Increase in the number of carbon atoms of alkyl resulted in decreased reaction efficiency, reduced adhesion, somewhat slower biodegradation, and declined desizability. In addition to the chain length, the level of starch quaternization also showed marked effects on the viscosity, adhesion-to-fiber, aerobic biodegradation, and desizability. Based on the reaction efficiency, adhesion-to-fiber, aerobic biodegradation, and desizability, TMACHP cornstarch was superior to the TEACHP and TPACHP ones.