Study On Preparation Of Cationic/Amphoteric Polyelectrolytes With High Charge Density By Hofmann Reaction

At present, the sorts of polyacrylamide as additives in papermaking is single, and the effective content of product is low-lying. To improve the present situation, the following content is studied in this paper. In chapter 2, a part of influential factors on concentration and stability of a series of high - density sodium hypochlorite solution prepared by the chemical method were analyzed. Several effective methods for increasing the concentration and stability of sodium hypochlorite aqueous solution was given. In chapter 3, the effect of reaction conditions on Hofmann reaction of RAM was reviewed, and the best condition to enhance the effective content of product was given. As a result, the effective content of PVAm is about 10%, which is much more 2~3% than 7~8% reported by literature. In chapter 4, the functional groups, amino, carboxyl, isocyanate and N-chloroamide group, formed in the Hofmann reaction of polyacrylamide (PAM) were characterized by means of colloidal titration, IR and XPS spectra., espectially the change of isocyanate and urathane group will be reported. In chapter 5, the Hofmann degradation of non-ionic polyacrylamide(NPAM) and part-hydrolytic polyacrylamide(APAM) were studied in this paper. Results show that the amphoteric primary amine (AmPAM ) can be prepared by changing mixture ratio of reactants, time and temperature, which the ratio of amine/carboxyl can be adjusted from 0.97 to 42.30. And the product of ARAM by Hofmann degradation may have good application because of w (N-Cl) =7.2%.