Introduction of N,N-Dimethylaminoethyls onto Maize Starch for Strong Bonding and Easy Removal for Polyester Warp Sizing

Dimethylaminoethyl (DAE) starch was derived by the tertiary amination of acid-converted maize starch (ACS) with 2-dimethylaminoethyl chloride hydrochloride (DAEC·HCl) for strong bonding to polyester fibers and easy removal from sized yarns. A series of DAE derivatives with differential degrees of substitution (DS) of DAE substituents were prepared through the variation in mole ratio of DAEC·HCl to ACS charged into starch amination. The DAE starch was characterized by FTIR spectroscopy, DS value, amination efficiency and paste viscosity. The bonding strength was measured using a legal method (FZ/T 15,001–2008) while the desizability was accessed by Hank sizing and oxidant-alkali desizing. The results showed that the amination was able to significantly improve the bonding strength to polyester fibers under mild acidic condition and could prevent the difficulty encountered in quaternized starch desizing. The DAE starch could compete with ACS in desizability during oxidant-alkali desizing. As a result, introduction of DAE groups onto ACS was an effective method for achieving a starch based sizing material with strong bonding and good desizability. Based on the achievements obtained in this work, the DAE starch with a DS value of 0.037–0.058 DAE substituents showed potential application in polyester warp sizing.