In this thesis, the cationic starch was hydrophobically modified with benzoyl group which was selected as the hydrophobic group, and preparation and properties of cationic starch benzoate were studied.

Preparation and application of quaternary ammonium type cationic starch flocculant;

Study on synthesis of quaternary ammonium type cationic starch;

This paper preliminarily studied the strengthening of the quaternary ammonium type cationic starch on wastepaper recycling.

The cationic starch ether was prepared by the reaction of starch (Ⅰ) and 3 chloro 2 hydroxypropyltrimethylammonium chloride (Ⅱ) in the solvent of methanol under alkaline condition.

The emphasis was laid on its application in preparing paper chemicals such as polyamideamine-epichlorohydrin(PAE)and its modification product as well as chlorohydroxypropyltrimethylammonium chloride(CHPTA)which is an etherification agent used to prepare quaternary ammonium type cationic starch.

The effects of the experimental conditions of the molar ration of cornstarch and quaternaries cation, pH, reaction temperature and reaction time on reaction were investigated.