Preparation Of Chitosan Quaternary Ammonium In A Kind Of Ionic Liquid

Chitosan (CS), folly or partially deacetylated product of chitin, is the secondly most abundant polysaccharide after cellulose which has many properties such as good biocompatible, biodegradable, hydrophilic, antimicrobial resistance and so on. It has been widely used in biomedical, food packaging, and environmental protection. In this paper, N-(2-hydroxy)-propyl-3-trimethylammonium chloride chitosan has been prepared. The main conclusions are as follows:(1) Summary of chitosan and its resources. In this section, chitosan and its applications and commonly used modification methods were introduced. Application of the ionic liquids in the process of natural polymer resources was reviewed. The main content and significance of this thesis project were described.(2) GTMAC-m-CS was synthesized through a homogeneous reaction of GTMAC with CS in AmimCl. The influencing factors, such as reaction time, temperature, nEPTAC/n.NH2 and pretreatment of CS in the modification were investigated and the properties of GTMAC-m-CS were investigated, based which the optimal reaction conditions of this reaction was obtained, namely, the reaction time was 6 h, the suitable ratio was nEPTAC/n.NH2=3:1, the The optimum reaction temperature was 80℃.The reaction site and the degree of substitution of GTMAC-m-CS were measured by FTIR, 1H NMR, 13C NMR, which showed that the reaction site was on -NH2. The maximum degree of substitution of GTMAC-m-CS was 118%. The XRD, TG, DSC and DMA were used to characterize the changing of the internal structure of GTMAC-m-CS, the thermal stability and the dynamic mechanical properties. The results showed that the thermal decomposition temperature of GTMAC-m-CS, thermal decomposition enthalpy and glass transition temperature decreased with the degree of substitution reaction increase.(3) The kinetics of homogeneous reaction of chitosan in AmimCl was studied. The effects of initial chitosan primary amino concentration and different reaction temperatures on the quaternization reaction rate were measured. The results showed that quaternization reaction rate increased with increasing initial chitosan concentration and reaction temperatures. The reaction kinetic equation were determined based on the experimental data. The reaction order for quaternization reaction of chitosan was determined.(4) The studies on interaction between GTMAC-m-CS and surface active ILs. GTMAC-modified chitosan (GTMAC-m-CS) was synthesized through nucleophilic substitution of GTMAC on CS which was dispersed in isopropanol. The obtained GTMAC-m-CS was characterized by FTIR and 1H NMR methods. The interactions between GTMAC-m-CS and surface active ILs—1-dodecyl-3-methylimidazolium bromide(C12mimBr), 1-tetradecyl-3-methylimidazolium bromide (C]4mimBr), 1-hexadecyl-3-methylimidazolium bromide(C16mimBr) were investigated by surface tension and conductivity methods. The amount of surface active ILs adsorbed on GTMAC-m-CS, surface pressure, as well as thermodynamic parameters were obtained. Based on the analysis of solution properties of GTMAC-m-CS/IL, the interaction model of GTMAC-m-CS/IL was proposed.