Obtaining and Studying the Properties of Highly Substituted Cationic Starches of Different Botanical Origins Crosslinked with Epichlorohydrin

A method of one-stage cationization and crosslinking of potato and corn starches using epichlorohydrin as a crosslinking agent is developed. Samples of crosslinked cationic potato and corn starches with controlled viscosity properties are synthesized, whose aqueous dispersions exhibit pseudoplastic properties at various temperatures and degrees of crosslinking. It is found that the obtained crosslinked cationic starches retain their granular structure, and the degree of crystallinity of the samples slightly decreases regardless of the temperature (20–45°C), reaction time (24–96 h), and dose of the crosslinking agent (0.05–5.0%). It is shown that the rate of flocculation of kaolin suspensions increases with the increasing dose of the flocculant for all types of cationic starches. Regardless of the dose, the maximum sedimentation rate of kaolin in model systems is observed when using crosslinked cationic potato starch. The results obtained can be used to develop a technology for producing biodegradable crosslinked cationic starches as effective flocculants for cleaning aqueous solutions as an alternative to synthetic polyacrylamide derivatives.