Preparation Of Cationic/Amphoteric Hydroxyethyl Cellulose And Study On The Characterities Of Their Aqueous Solution

For the last few years, research and development of the cellulose derivatives havebecome more and more importance because of the wide source and the biodegradability ofcellulose. Hydroxyethyl cellulose (HEC) derivatives bearing cation/amphoteric ion groupwould be widely used in the future because they possess the properties of both cation/amphoteric and hydroxyethyl cellulose. The thesis focused on the synthesis ofcationic/amphoteric hydroxyethyl celluose by dry process, Meanwhile, the viscositybehaviours of their aqueous solutions were studied.In presence of alkaline catalyst, the cationic hydroxyethyl cellulose (CHEC) bearingquaternary amino groups was prepared via the reaction of the hydroxyethyl cellulose withglycidyltrimethylammoniumchloride (GTA) using the dry process. The cationichydroxyethylcellulose with different degree of substitution (DS) of 0.1~0.6 were prepared bymodified process. This process improved the space-time yield, because the cationic reactioncan be processed in high solid content. The cationization process was so efficient that itneeded only a little of solvent, consumed the lowest energy and gave the most reactionefficiency. In this process, the special mixer or squeezer was in no need and a satisfactoryresult can be obtained by using the common stirrer. Different factors, that affect the reactionefficiency(RE) and DS were studied including the amount of new catalyst and GTA, reactiontime(h) and temperature(℃).The optimum reaction condition was well presented by themethod of uniform design and Monte Carlo simulated. The results indicate: when reactionconditions are GTA to HEC rate of 1.658mmol/g, Cat to HEC rate of 5.929 mmol/g,reaction time of 4h, reaction temperature of 70℃, RE can reach 85%;when reactionconditions are GTA to HEC rate of 2.156 mmol/g, Cat to HEC rate of 1.119mmol/g, reactiontime of 9.8h, reaction temperature of 55℃, DS can reach 0.49.The preparation of cationichydroxyethyl cellulose by dry process is not reported.An amphoteric monomer N-carboxymethyl-N,N-dimethyl-N-allylammoniumhydroxide inner salt (CDAH) was synthesized by the reaction of dimethylallylamine withsodium chloroacetate. N-(3-chloro-2-hydroxypropyl)-N-(carboxymethyl) -N,N-dimethylammonium hydroxide (CCDH) was produced by the reaction of CDAH withhypochlorite. In presence of alkaline catalyst, the amphoteric hydroxyethyl cellulose (AHEC)bearing betaine group was prepared via the reaction of the CCDH with hydroxyethylcelluloseusing the dry process.Meantime, viscosity behaviours of CHEC and AHEC were studied. The results show thatcationic hydroxyethyl cellulose in water has typical viscosity characteristics of polyelectrolyte.With the increasing of CHEC concentration, the viscosity behaviour decreases. As the radiusof the salt cationic ion increases, or as the salt NaCl concentration increases, the reducedviscosity decreases. The obvious viscosity behaviour of anti-polyelectrolyte solution wasobserved in aqueous AHEC solutions containing NaCl. With the increasing of AHECconcentration, the viscosity of solution behaviour increases.