A Study on the Preparation of Quaternary Ammonium Salt of Chitosan by Open-loop Method of Epoxy Derivatives

Reported in this paper is a practical method to synthesize quaternary ammonium salt of chitosan(HACC) in high substitution rate by reaction of chitosan with 2,3-epoxypropyltrimethyl ammonium chloride.The reaction conditions were screened and the main factors were analyzed independently.The optimized condition factors were determined as follows:mole ratio of the reactants n(CTS):n(GTA)=1:4,molecular weight of chitosan MWc=320 000 g/mol,alkaline pretreatment time ta=14 h,moisture content of the pretreated chitosan w(H2O)=20%,reaction pH=7,reaction temperature 75 ℃,reaction time 8 h.The substituted product was analyzed by IR,SEM and TG/DTG.The analysis results indicate that the substitution occurred mainly on the amino groups of chitosan.Compared to unsubstituted chitosan,the substituted product has a smaller particle size and slightly lower thermostability.