Synthesis Of Quanternary Ammonium Salt Of Chitosan And Studies On Its Characteristics

Chitosan(CS) is a kind of rich natural polymer .It has recently attracted great attention of numerous investigators in different countries because of their unique chemical and biologicalproperties.Derivative of chitosan, 2-Hydroxypropyltrimethyl Ammonium Chloride Chitosan(HACC) has good water solubility, moisture absorption properties, antimicrobial activity and flocculating properties. The applications of quantemary ammonium salt of chitosan include uses in variety of areas, such as cosmetics, pharmaceutical and medical applications, and waste treatment.The first work of this paper is measuring physical properties of chitosan. Degree of deacetylation(DD) of the three different chitosan are determined by acid -base titration or acid -base conductometric titration.The MW of chitosan I and II by viscometry is 1.0 X 106and 9.5 X 105,respectively.In room temperature the relationship between the viscosity of the solution and the concentration of acid, the concent rations of chitosan, the storing time and salt concentration have been determined.The quantemary ammonium salt of chitosan has been synthesized in the heterogeneous system, by the reaction of chitosan with 2,3-epoxypropyltrimethyl ammonium chloride(EPTAC). The factors affect on the degree of substitution of product, yield and apparent viscosity, such as the mol rates of EPTAC with -NH2, reaction temperature, reaction time and the content of water in system have been discussed in detail. FTIR spectrometer and UV spectrometer are used to characterize the structure of the derivative and it is proved that substitution reaction mainly occurs on the -N element .The particle size and morphology of chitosan and quantemary ammonium salt of chitosan are analysised by comparing photos of their scanning electron microscope (SEM). The degree of substitution (DS) of HACCis determined by acid -base conductometric titration. An error in current formula of DS has pointed out and a correct formula has presented.On the base of experience of above experiment, the reaction conditions of HACC were systematically investigated through orthogonal design, and then the best conditions are found. Water-solubility and dependence of pH are studied. The results show that HACC has better water-solubility and stability under the different pH. At the same time the factors affect on the apparent viscosity and stability of HACC solution, such as concentration of acid, the concent -rations of HACC, temperature, the storing time, pH and salt concentration, have been discussed in detail.Flocculation experiments are carried out for treatment of wastewater from the production of sodium alginate and refinery wastewater with CS and HACC as flocculants respectively. The factors affect flocculating effect, such as pH, dosage of flocculants, settlement time and bentonite have been discussed in detail. The results show that HACC has the higher the rates of removal COD or oil than CS. The reduced rates of COD and oil are 88.4% and 95.6%. Flocculating effect mechanism is also discussed in this paper.This series suitable synthesis conditions are high-yield, simple-operating. Products have good water-solubility, stability and high flocculating effect compared with documents.