【摘要】 以高直链玉米淀粉为原料 ,甲磺酸为催化剂 ,制备一系列不同取代度的淀粉醋酸酯 ,研究了不同反应时间、温度、催化剂用量等对取代度的影响。结果表明 :反应时间越长 ,取代度越大 ,特性粘度变小 ;随着反应温度的升高 ,取代度增大 ,但特性粘度却明显降低 ;随着酸与酸酐用量的提高 ,取代度逐渐提高 ,特性粘度下降 ;增加 MSA用量 ,可大大提高取代度。应用 FTIR、XRD、DSC等近代测试手段 ,对淀粉醋酸酯样品进行了结构表征。更多还原

【Abstract】 Starch acetates with different degree of substitution have been synthesized from high amylose starch, glacial acetic acid and acetic anhydride using methyl sulfonic acid(MSA) as an esterification catalyst. The influences of the reaction conditions such as reaction time, reaction temperature, glacial acetic acid/acetic anhydride content and amount of MSA, on the degree of substitution of the starch acetates have been investigated. It has been found that (a) the degree of substitution increases by prolonging reaction time or increasing temperature, however, the intrinsic viscosity of the starch acetates decreases; (b) the degree of substitution increases with increasing the glacial acetic acid/acetic anhydride content and the amount of MSA; (c) some typical absorption of the starch acetates appeared in FTIR spectra increases with increasing of the degree of substitution; (d) the crystal structure of the pure starch is destroyed during the esterification process and forms more disordered structure as verified by the X ray diffraction analysis; (e) the melting point of the starch acetate sample is 94°C lower than that of the pure one.更多还原