Dry preparation of cationic starch with high degree substitution by the method of alkaline catalysis

High degree substitution cationic starch is prepared from starch with N-(2,3- epoxypropyl)trimethylammonium chloride(GTA) as cationic agent and KOH as catalyst by a dry process.The effects of GTA,KOH,reaction temperature and reaction time on the degree of substitution of products are carefully discussed.The result is when the mass ratio between GTA and starch is 1∶1.8,the mass ratio between KOH and starch is 1∶50,the reaction temperature is 85 ℃ and the reaction time is 3 h ,the mass percent of water in reaction system is 20%～30% ,the degree of substiution is up to 0.54.