| Abstract: | CONCLUSION. It was shown that it is possible to produce cationic starch derivatives with high degrees of substitution up to 1.4. The products can be easily prepared with 3-chloro-2-hydroxypropyltrimethylammonium chloride in a suspension of starch and ethanol/water, homogeneously in DMSO, and under dissolution applying aqueous NaOH with 2,3-epoxypropyltrimethylammonium chloride. The starting material does not influence the DS value except in the case of waxy maize starch in a heterogeneous medium. High degrees of substitution up to 1 are obtained by a one-step reaction with a molar ratio of cationi-zation agent per AGU of 2 in aqueous sodium hydroxide. The DS value reached by these reactions can be adjusted by the amount of cationization agent used in the reaction. The aqueous sodium hydroxide medium shows the highest efficiency for a molar ratio of agent/starch of 2, but more liquid must be applied compared to the slurry reaction in ethanol/water. For higher DS values (up to 1.5), a second cationization step is necessary. The obtained starch materials are soluble in cold water and show promising properties. Recently, their efficiency as flocculation agents in waste-water clarification was shown [21]. Moreover, the cationic derivatives show a significant antibacterial behavior [22]. |
|---|
