利用机械活化木薯淀粉制备淀粉磷酸酯的工艺研究

由于淀粉是一种多晶高聚物,其颗粒中一部分分子排列成疏松的非晶区,另一部分分子则排列成高度有序的结晶区,磷酸盐不易深入到颗粒内部,反应往往只能发生在颗粒表面,导致淀粉反应活性和反应效率较低,难以得到高取代度的产物.今利用自制的搅拌球磨机将普通木薯淀粉进行机械活化预处理,正磷酸盐为酯化剂,尿素为催化剂,干法制备淀粉磷酸酯.探讨了活化时间、磷酸盐用量、pH值、反应温度、反应时间和尿素用量对取代度(DS)和反应效率(RE)的影响,确定了最佳反应条件:活化时间1.5 h,磷酸盐用量12%,pH4.5,反应温度150℃,反应时间2 h,尿素用量2%.研究结果表明:机械活化预处理方法能显著提高木薯淀粉磷酸酯的DS和RE,表明机械活化能有效地提高木薯淀粉的化学反应活性.最佳工艺条件下木薯淀粉磷酸酯的DS和RE为0.0900和0.933.

Synthetic Technics of Starch Phosphate with Mechanically Activated Cassava Starch

Starch is a morphologically complex polymer substance which consists of loose amorphous regions interspersing with highly regular crystalline regions, therefore it is difficult for the phosphate to contact with the inner molecules of the starch, which will result in low starch activity, low reaction efficiency and producing starch phosphate with low degree substitution (DS) for the esterification reaction of the starch. In this work, the starch phosphate was synthesized by dry process, during which, a custo...