Abstract: Chitin is dissolved in NaOH/urea aqueous solution at low temperature.Quaternized chitin (QC) was synthesized using glycidyl trimethyl ammonium chloride as etherifying agent.The products were characterized by 1H NMR,FT-IR,XRD and thermal analysis apparatus.The flocculation properties for montmorillonite suspensions (MMT) were studied using QC as cationic flocculant.Factors affecting flocculation properties were investigated respectively,including the flocculant concentration,flocculation time,temperature and pH value.The results showed that QC was successfully prepared in NaOH/ urea aqueous solution,and the substitution degree (DS) was 0.41.Aggregation structure and thermal stability of polysaccharides were significantly changed because of the introduction of quaternary ammonium groups.When concentration was 0.5% and flocculation time was 30 min,QC had better flocculation effects for MMT in a quite wide range of pH values at room temperature.The highest flocculating efficiency (FE) reached 98%.

Key words: quaternized chitin, homogeneous synthesis, flocculant