Characterization and Synthesis of Quaternary Ammonium Salt of Chitosan by Open-Loop Method of Epoxy Derivatives

Abstract

Quaternary ammonium salt of chitosan (HACC) was synthesized by the reaction of chitosan(CTS) and 2, 3-epoxypropyltrimethyl- ammonium chloride(GTA) in isopropanol. The influence factors of the degree of substitution of synthetic reaction, such as the molar ratio of reactants, the reaction time, temperature and so on were discussed by single factor experiments.The results showed that the optimal conditions for the preparation were nGTA: nCTS=4:1, the reaction time 8h, the reaction temperature 75°C, the reaction pH value 7, the alkalization time 14h, the molecular weight of chitosan 320000g/mol, the moisture of reaction system 20%. The structures of HACC and CTS were characterized by infrared spectrum, the appearances of morphology of HACC and CTS were researched by scanning electron microscopy, the thermal stabilities of HACC and CTS were studied by thermogravimetry. The results showed that the substitution reaction mainly occurs on the N element, modified derivatives had significant changes in appearance and size, and lower thermal stability.