反应条件对马铃薯羧甲基淀粉黏度和取代度的影响

Effect of Reaction Conditions on the Degree of Substitution and Viscosity of Carboxymethyl Starches

以马铃薯淀粉为原料,通过与氯乙酸的反应和采用"两步碱化法"合成了羧甲基淀粉。探讨了在不同的反应条件下,羧甲基淀粉取代度和黏度之间的关系。结果表明,随着碱化时间、碱化温度、醚化时间、醚化温度、氢氧化钠以及氯乙酸用量的改变,羧甲基淀粉取代度的高低和其黏度的变化不呈单调关系。结论:由于氢氧化钠的双重作用,在一定范围内,取代度增大而粘度减小。

The work reports the preparation of carboxymethyl starch （CMS） by the reaction of potato starch with chloroacetic acid and by using a two-step alkalization procedure. Relationships between degree of substitution （DS） obtained under various reaction conditions and viscosity of CMS were studied. The resuhs showed that the dependence of viscosity on DS was not uniform along with changes in duration and temperature of alkalization and etherification, and amounts of NaOH and chloroacetate. The viscosity decreased with increasing DS in a cer- tain region due to the dual effects of NaOH.