Abstract:

In order to obtain an excellent sizing effect for cotton high-count yarn, a hydrophilic modified starch size-carboxymethyl corn starch (CMCS) was synthesized from natural corn starch, chloroacetic acid and sodium hydroxide as raw material, etherifying reagent and catalyst by a microwave-assisted process. The molecular structure and granular morphology of the products were characterized by FT-IR and SEM. The results show that carboxymethyl groups are successfully introduced into corn starch macromolecule and starch granules are damaged by varying levels and their integrity is destroyed. The studies for physicochemical properties of CMCS show that the intrinsic viscosity and apparent viscosity of CMCS decrease, rheological property is enhanced, the solubility, swelling power, paste clarity and retrogradation resistance are improved, the blue value reduces, suggesting the degradation of amylase. The gelatinization temperature decreases, which indicates that gelatinization properties and paste processing performance are improved. The results of the adhesion experiment show that the adhesion force of CMCS is enhanced by as much as 27. 9% compared with nature corn starch(NCS), and the adhesion force increases with the increase of degree of substitution. The results of sizing experiments on 9. 67 tex pure cotton yarns show that the mechanical properties of CMCS sized yarns are significantly improved, the tensile strength enhancement and abrasion resistance enhancement increase by 118. 5% and 88. 7%, respectively, and the elongation reduction is 29. 7% lower than that of NCS sized yarns.

Key words: hydrophilic modified starch size, microwave, carboxymethylated corn starch, substitution degree, physical and chemical property, cotton yarn sizing