Abstract: Carboxymethyl starch hexanoate (CMSH) with high viscosity and thermal stability was prepared by esterification of carboxymethyl starch (CMS).The chemical structure and thermal stability were characterized by IR and TG.The relative hysteresis area, temperature sensitivity and factors affecting viscosity of CMSH, such as mass percentage of hexyl (MP_hexyl), concentration, shear rate and temperature, were studied using Brookfield R/S-CC Rheometer.The result indicates that temperature sensitivity, thermal stability and viscosity can be improved by introducing hexyls into CMS.Initial decomposition temperature(IDT)of CMSH increased from 260℃ to 300℃, the viscosity was also increased when compared with CMS because of the hydrophobic aggregation of hexyls, and the viscosity value reached 32000 mPa·s at MP_hexyl of 11.8%.However, the shear resistance and the relative hysteresis area can not be improved by introduction of hexyl group.

Key words: carboxymethyl starch, esterification, viscosity, hydrophobic aggregation, shear rate

摘要： 以羧甲基淀粉(CMS)为原料制备了高黏度、高热稳定性的羧甲基淀粉己酸酯(CMSH)。用IR和TG对产物进行了结构和热稳定性质研究;通过Brookfield R/S-CC流变仪对羧甲基淀粉己酸酯溶液黏度性质和影响因素,如己酰基质量分数、浓度、剪切力、温度及溶液黏度的剪切恢复性质、温度敏感性质等进行了详细研究。结果表明,引入己酰基基团后,可以降低黏度对温度的敏感性,显著提高羧甲基淀粉的热稳定性和溶液的黏度值。但己酰基团的引入,不能提高CMS溶液黏度的抗剪切性和剪切恢复性。当己酰基质量分数为11.8%时,羧甲基淀粉己酸酯的初始热分解温度由260℃提高到300℃;溶液的黏度值由420 mPa·s提高到32000 mPa·s。

关键词: 羧甲基淀粉, 酯化, 黏度, 疏水缔合, 剪切速率