Preparation of cationic starch of low substitution and application in paper making

The cationic starch of low substitution was prepared by watering process with cornstarch and 3-chloro-2-hydroxypropyl-trimethyl-ammonium chloride(CTA).The effects of the amount of catalyst,n(NaOH)/n(CTA),the reaction temperature and the time of the reaction on the substitution,were discussed.The optimal experimental conditions are as follows:starch 50 g,catalyst 0.016 0 mol,n(NaOH)/n(CTA)=1.2∶1,the reaction temperature is 40 degrees,the reaction time is 2 h.The low substitution of cationic starch prepared could reach 0.079%,the viscosity of 0.5% pasty fluid was 1.07.And some applications in paper making were summarized.