Preparation And Application Of The Grafting Copolymers Of Dimethyl Diallyl Ammonium Chloride On Chitosan

Chitin is a kind of abundant natural macromolecule resources. Chitosan, which deacetylate from chitin, possess excellent bio-degradation and bio-compatibility. Chitosan is the only natural alkaline polysaccharide macromolecule, the studies on modification and application of chitosan and its derivatives have attracted numerous investigators. And chitosan, which is a kind of natural organic saccharide macromolecule, has been used in all kind of industries, such as foodstuff industry, environmental protection, functional material, medicine and sanitation, agriculture etc. The preparation and application of chitosan grafted copolymers, which is prepared by irradiation method, is still a new brand research project.The following substance is contained in this paper: 1. The structures and properties of chitin and chitosan, the status quo of manufacture and research of chitin and chitosan all over the world were reviewed. The current situations of scientific researches on chitosan and its derivatives were introduced. The studies progress of chitosan and its derivatives, which were used as heavy metal ions adsorbent and flocculant in water treatment, were introduced.2. In this thesis, the grafting reaction, which DMDAAC was grafted on chitosan utilizingγ-ray of ⁶⁰Co irradiation resources, was studied. The optimal methodology of the reaction is: full of N₂, the doseage of radiation is 2.0kGy, pH=6, the proportion of DMDAAC solution, which the mass fraction of DMDAAC is 60%, with chitosan is 4mL/g, grafting ratio is above 24%.3. The grafted copolymer, which derived from the optimal condition, was characterized. The result of FTIR spectroscopy, X-ray diffraction, SEM and thermogravimetry, indicated that DMDAAC has been grafted on chitosan, and the subsequent application experiments have proved this.4. The mechanisms of the syntheses of grafted copolymer by radiation and chemical initiation methods were discussed. And the polymerization mechanism of DMDAAC by irradiation was also discussed.5. The adsorption abilities of the grafted copolymer used as heavy metal ions adsorbent were inferior to chitosan, but it is insoluble in water when pH>5 and it can be reused, so it still can be used as adsorbent.6. The results of flocculability comparative experiment of seven flocculants indicated the following conclusions. When the pH value is same, the mass of grafted copolymer need less and obtain a better turbidity removal effect. That is to say, the graftede copolymer has better flocculability than other flocculants to Kieselguhr and Bentonite Simulated Water, and the pH value has little affection to its flocculability. The grafted copolymer has similary flocculability to chitosan for the Water of First Washed Rice at low mass (below 10mg/L), and it has better flocculability than other flocculants.