Microwave-assisted Synthesis, Characterization, and Textile Sizing Property of Carboxymethyl Corn Starch

In this work, carboxymethylated corn starch (CMCS) was synthesized using the microwave-assisted method with native corn starch (NCS) as the raw material, sodium hydroxide as the catalyst, and chloroacetic acid as the etherifying reagent. By varying the amount of etherifying reagent added, CMCS with degrees of substitution (DS) ranging from 0.034 to 0.070 were obtained. The molecular compositions, crystal structures, and granular configurations of the products were characterized using FT-IR, XRD, and SEM, respectively. The physicochemical characteristics of CMCS, such as hydration, rheological behavior, and gelatinization property, were studied systematically, and the results indicated that the aforementioned properties significantly changed. The intrinsic and apparent viscosities of CMCS decreased, whereas the solubility, swelling power, and anti-retrogradation were improved. The results from the Brabender viscosity curve analysis showed that the gelatinization temperature of CMCS decreased, which indicated that the gelatinization property and paste processing performance of CMCS were enhanced. These changes were attributed to the combined effects of both microwave radiation and carboxymethylation modification. To investigate the textile sizing property of CMCS, pure cotton yarns (60S) were sized using CMCS, NCS and PVA. The results showed that CMCS had considerably improved sizing and desizing properties compared with NCS, and some aspects of the performance were even close to those of PVA. The results of these tests indicated that this novel green sizing agent (CMCS) could have promising applications in textile manufacturing and become an ideal substitute for PVA.