Preparation And Properties Of Chitosan Derivative Sulfate

In this paper,chitosan and alkylated chitosan were sulfated by gas SO₃.After neutralization,the chitosan sulfate and two chitosan-based surfactants were obtained.The interactions of these products with traditional cationic surfactants were also been explored.The main works are as follows:?1?Preparation and properties of chitosan sulfate?CHS?.The gas SO₃ was used as sulfating agent to react with chitosan in a mixed solvent of N,N-dimethylformamide,formamide and dichloroacetic acid at 50?for 2 h.After neutralization,the CHS was obtained.The FT-IR,elemental analysis and CP-MAS ¹³C NMR were used to identify the structure of product.The results indicated that the target product was synthesized successfully.The interactions of CHS with cetyltrimethylammonium bromide?CTAB?,dodecyltrimethylammonium bromide?DTAB?and decatrimethylammonium bromide(D₁₀TAB)were investigated by interfacial tensiometry,fluorescence spectrometer,ultraviolet/visible spectrophotometer?UV/vis?,Zeta potential and transmission electron microscope?TEM?.It was found that the CHS can reduce the critical aggregation concentration?CAC?of CTAB,DTAB and D₁₀TAB.Besides,the CHS can promote these surfactants to form morphology-rich aggregates.?2?Synthesis of N-decyl chitosan sulfate(N-D₁₀CHS).The decanal was used as alkylating agent to react with chitosan in ethanol solvent to form Schiff base.After reduction by NaBH₄,the N-decyl chitosan was obtained.The gas SO₃ was used as sulfating agent to react with N-decyl chitosan in a mixed solvent of N,N-dimethylformamide,formamide and dichloroacetic acid at 50?for 45 min.After neutralization,the N-D₁₀CHS was obtained.FT-IR,elemental analysis and ¹H NMR were used to identify the structure of product.The results showed that target products were synthesized successfully.The surface activity and aggregation behavior in aqueous of the product were measured by interfacial tensiometry and TEM.The results showed that the CAC of the N-D₁₀CHS was 2.5 mg/mL,and the surface tension?_CAC at this concentration was 50 mN/m.When the concentration of N-D₁₀CHS was obove its CAC,the spherical aggregates of 100-300 nm can be observed by TEM.The interactions of N-D₁₀CHS with CTAB,DTAB and D₁₀TAB were investigated by fluorescence spectrometer,UV/vis and TEM.It was found that the N-D₁₀CHS could reduce the CAC of CTAB,DTAB and D₁₀TAB.Besides,the N-D₁₀CHS can promote these surfactants to form morphology-rich aggregates.?3?Synthesis and properties of N-dodecyl chitosan sulfate?N-DCHS?.The lauraldehyde was used as alkylating agent to react with chitosan in the mixed solvent of acetic acid,water and ethanol to form Schiff base.After reduction by NaBH₄,the N-dodecyl chitosan was obtained.The gas SO₃ was used as sulfating agent to react with N-dodecyl chitosan in N,N-dimethylformamide solvent at 50?for 45 min.After neutralization,the N-DCHS was obtained.FT-IR,elemental analysis and ¹³C NMR were used to identify the structure of product.The results showed that target products were synthesized successfully.The surface activity and aggregation behavior in aqueous of the product were measured by interfacial tensiometry and TEM.The results showed that the CAC of the product was 0.5 mg/mL,and?_CAC was 40.5 mN/m.When the concentration of N-DCHS was obove its CAC,the spherical aggregates of 300-1000 nm can be observed by TEM.The interactions of N-DCHS with CTAB,DTAB and D₁₀TAB were investigated by fluorescence spectrometer,UV/vis and TEM.It was found that the N-DCHS could reduce the CAC of CTAB,DTAB and D₁₀TAB.Besides,the N-DCHS can promote these three surfactants to form morphology-rich aggregates.