己酰酯化羧甲基淀粉的制备及粘度性质研究

Preparation and viscosity properties of hexylated carboxymethyl starch

摘要:

以羧甲基淀粉（CMS）为原料，己酰氯为酯化试剂，二甲基亚砜（DMSO）为溶剂，吡啶为有机碱合成了己酰酯化羧甲基淀粉（HCMS）。研究了反应温度、反应时间、催化剂用量、溶剂用量对己酰酯化取代度和反应效率的影响，确定了最佳反应条件为：5 g CMS/40 mL （0.125 g/mL）（DMSO）, 反应温度为50 ℃, 反应时间为30 min, 有机碱用量为1.0 g（0.025 g/mL）。通过IR、Brookfield R/S - CC 流变仪对产物进行了结构及溶液粘度性质研究。通过对不同浓度和不同己酰酯化取代度（DShexyl）的羧甲基淀粉溶液粘度性质（剪切速率范围 = 0 ~ 500 s-1）结果表明，达到临界聚集浓度（2.0% w/w）时，适当己酰基取代度（DShexyl = 0.3）的HCMS, 可以使羧甲基淀粉溶液的粘度值由420 mPa.s 提高到34000 mPa.s（γ = 5 s-1）。

Abstract:

Hexylated carboxymethyl starch with high viscosity was prepared by esterification of hexanoyl chloride and carboxymethyl starch using dimethyl sulfoxide (DMSO) as solvent and pyridine as catalyst. The reaction conditions, such as the reaction temperature, time, solvent volume and the amount of catalyst were investigated and the optimum reaction conditions were obtained as follows: 5 g CMS/40 mL DMSO (0.125 g/mL), reaction temperature 50 ℃, reaction time 30 min, organic base 1.0 g（0.025 g/mL）. Hexylated carboxymethyl starch was characterized by IR and the viscosity properties of solution were investigated using Brookfield R/S - CC rheometer. Result of viscosity properties of different concentration and DShexyl of HCMS indicates that the viscosity value of HCMS can increase to 34000 mPa.s（γ= 5 s-1）at DShexyl of 0.3 when the concentration reaches critical aggregation concentration(2.0% w/w).