Abstract: 3-Chloro-2-hydroxypropyl dimethyl dehydroabietyl ammonium chloride grafted N,O-carboxymethyl chitosan oligosaccharide (CHPDMDHA-g-N,O-CMC) was obtained through the grafting reaction between 3-chloro-2-hydroxypropyl dimethyl dehydroabietyl ammonium chloride (CHPDMDHA) and N,O-carboxymethyl chitosan oligosaccharide (N,O-CMC) with 25% NaOH aqueous solution as catalyst.The structure of CHPDMDHA-g-N,O-CMCs was confirmed by FT-IR and ¹H NMR,and the grafting degree (D_Q) of CHPDMDHA-g-N,O-CMCs was determined by elemental analysis.The critical micelle concentration (C_CMC) and surface tension (γ_CMC) were determinated according to the variation of the surface tension of CHPDMDHA-g-N,O-CMCs in aqueous solution with the concentration.The emulsifying power of CHPDMDHA-g-N,O-CMCs was investigated according to the stability time of emulsion which was formed by oscillametric method and composed of water and benzene.The experimental results showed when the grafting degrees of CHPDMDHA-g-N,O-CMCs were 18.7%,21.5% and 23.1%,the critical micelle concentrations were 4.82×10^-4,1.33×10^-4 and 7.50×10^-5 mol/L,the surface tensions at cmc ware 35.1,33.7 and 32.7 mN/m,respectively.The stability time of emulsion composed of 1.0 g/L CHPDMDHA-g-N,O-CMC,whose D_Q was 23.1%,aqueous solution and benzene at the same volume was up to 195s,which was the longest one among CHPDMDHA-g-N,O-CMC3,sucrose stearate and monoglyceride.

Key words: grafting modification, surface activity, emulsion power