Study On Oxidized Corn Starch By Potassium Permanganate

In this paper, oxidized starch by KMnO₄ on the condition of acidityis studied.KMnO₄ oxidization method has the advantages of high oxidativedegree, simple operation and low environmental pollution, so oxidizedstarch by KMnO4 has broad prospects.The research finds, in the process of KMnO₄ oxidizing starch on thecondition of acidity, that it is activated manganese dioxide but notpotassium permanganate that directly oxidizes starch. This mechanismsuccessfully explains the essence that the color of the emulsion changesin the process of KMnO₄ oxidizing starch. Based on that theory, theactivation energy of oxidization process is calculated at 73.83kJ/mol.Meanwhile, a variety of factors that affect oxidized starch byKMnO₄ are studied in this paper, including the temperature and theconcentration of KMnO₄, H₂SO₄ and starch milk, and theoretically probesall kinds of influences.The experimentation proves that the speed of the reaction willincrease when the temperature rises, the speed of the reaction willincrease 2～3 times whenever the temperature raises 10℃, and thechanges of temperature have little effect on the carboxyl content ofoxidized starch. If the dose of H₂SO₄ goes up, the carboxyl content ofoxidized starch will increase, the reaction time will shorten, but the fieldsof the oxidized starch will decrease. If the concentration of KMnO₄ rises,the carboxyl content of oxidized starch will increase, the speed of thereaction will increase, but the fields of the oxidized starch will decrease.The higher the concentration of starch is, the bigger the speed of thereaction is, but the concentration of starch has little effects on thecarboxyl content of oxidized starch.The most proper conditions of KMnO₄ oxidizing corn starch are thatthe concentration of starch is 35%, that the amount of KMnO₄ is 4% ofstarch, that the amount of H₂SO₄(98%) is 1.28 times of KMnO₄, and thatthe temperature of the reaction is 55℃. The time of complete reaction isabout 70 minutes on those conditions. In addition, the analysis method of the carboxyl content of oxidizedstarch is still studied. It finds through experimentation, that thecoordination titration method is more accurate and simpler than thetraditional starch paste method.The oxidized starch has been widely used in many industrial fields,such as paper, textile and food. This paper summarizes its application,and some compared experimentations have been done for the applicationof the oxidized starch by KMnO₄ in paper and corrugated paper adhesive.The new development of the application of the oxidized starch isintroduced in this paper.