Preparation of oxidized corn starch in dry method assisted by kneader

Abstract

In this study, oxidized starch (OCS) with different carboxyl content was prepared by the dry method, with H2O2 as the oxidant and CuCl2 as the catalyst. The optimum conditions were obtained by an orthogonal experiment, under the carboxyl and carbonyl content of 0.6813 and 1.0416% respectively. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction and gel permeation chromatography characterized the structures of OCS, and the thermal, gelatinization, viscosity property and its viscosity stability were measured. The results demonstrated that the crystallinity decreased slightly and the A-type crystal remained unchanged after oxidation, and the molecular weight of OCS decreased greatly. The thermal decomposition temperature, apparent viscosity and setback viscosity also decreased. With the increase of carboxyl content in OCS, the cold-water solubility and paste transparency of OCS paste increased gradually, while the viscosity of OCS paste decreased, and the viscosity stability displayed a trend of first increasing and then reducing. The OCS obtained by a kneader had low solution viscosity and high viscosity stability, suitable for sizing high count warp yarns.