Preparation And Characterization Of Quaternary Ammonium Salt Of Carboxymethyl Chitosan

Chitosan(CS) is a kind of rich natural polymer ,It has recently attractedgreat attention of numerous investigators in different countries because of theirunique chemical and biologicalproperties.In this paper, Study on A new derivative of chitosan---preparation andapplication of the Quanternary Ammonium Salt of Carboxymethyl Chitosan.In this paper ,six parts of work were included:1. producing status quo of chitin ,chitosan all over the world and its thestructure and properties chitosan were reviewed. The moisture absorption andretention abilities, antibacterial properties of chitosan and its derivatives wereintroduced and as waste water flocculanting, absorbent.2. The first work is measuring physical properties of chitosan.Degree ofdeacetylation (DD) of chitosan are determined by acid-base conductometrictitration.The determine of molecular weight of chitosan and after depolymeriz-ation of chitosan through viscometry or gel pervasion chromatogram(GPC). 3. Water soluble chitosan derivatives, N, N, N-trimethyl-chitosan chloride(TMC), O-Carboxy- methyl-N-triMethylChitosan Quaternary ammonium salt(CMTMC), Carboxy methyl chitosan (CMC), O-Carboxymethyl-N,N-diMethyl-N-alkyl-chitosan chloride (CDACC) are synthesized by reaction ofchitosan with methyl iodide, chloroacetic acid and aldehydes respectively.Influences of reacting time, basify time, monormeric weight ratio on the degreeof substitution of Carboxymethyl of CMTMC are discussed. The result showsthat the optimized reaction condition were obtained as:reaction temperatureroom temperature, reaction time 8h, basify time 24h,m(TMC):m(monochloroacetic acid):m(sodium hydroxide)= 1:2.5: 7.5,and amounts ofisopropyl alcohol 60ml, sodium hydroxide concentration 50%.Under theoptimized conditions,the DS reached as high as 0.80.The modified chitosanderivatives are characterized by Fourier transform infrared (FT-IR) and ¹³Cnuclear magnetic resonance (¹³C-NMR) to observe changes in chemicalstructures. X-ray diffraction are applied focusing on changes in crystallity ofchitosan and its afinity for water. It shows quaternary and carboxyl methyl ofchitosan greatly reduced the hydrogen bonds among chitosan molecules andcrystallization,make CMTMC, TMC and CMC have stonger affinity for water.4. Chitosan of diferent substitution site was prepared and its structure wascharacterized by FT-IR, X-ray, ¹³C-NMR.its moisture absorption and retentionabilities was determined in different environment,such as CMTMC,N,O-CMC,TMC,OCMC,HA.The result shows that its moisture absorption and retention abilities size order is: CMTMC＞N,O-CMC＞OCMC＞HA＞TMC.Determination of the inhibitory bacterial properties of CMTMC. Theresults showed that the minimum inhibitore concentration of CMTMC toEcherichia coli, Staphylococcus aureus and Bacillus subtilis is 1μg/ml, 1μg/ml,2μg/ml, respectively. Antibacterial activities of CMTMC in acetic acid mediumis stronger than in water.5. The flocculation efficiency of CMTMC obviously exceed that of TMC onweste warter in sugar-refinery. The factors effect of flocculation capacity,suchas pH, flocculanting dosage and stirring time, also were discussed. The resultshows that the optimized flocculation efficiency condition(pH≥9, flocculantingdosage is 100mg/L-150mg/L,stirring time flocculation efficiency is above 76%.6. Comparation of adsorption on Cu²⁺, Pb²⁺ et al of heavy metal ion betweencarboxylmethyl chitosan and carboxymethyl chitosan resin. The result showsthat the absorptive capacity is maximum when pH was 6;The carboxylmethylchitosan seemed a little better than carboxylmethyl chitosan resin on Pb²⁺ andCd²⁺.