Synthesis of polyvinylamine by a modified Hofmann degradation of polyacrylamide and its solution properties

摘要

Four poly(vinylamine) chlorides (PVAmHCl) with about 82% degree of amination were prepared by the Hofmann degradation of polyacrylamide (PAM) with different degrees of polymerization (DPn). The behavior of dilute aqueous solutions of PVAmHCl was compared by viscosimetric, conductometric and potentiometric measurements. Dilute aqueous solutions of PVAmHCl showed typical polyelectrolyte characteristics. All amino groups attached to the hydrocarbon main chain were protonated at pH~4. The m value of PVAmHCl increased from 5.13 to 5.58 and the pKa value decreased from 7.48 to 7.26 with the increase of the intrinsic viscosity of PVAmHCl from 2.7 to 5.7. Equivalent conductivity of PVAmHCl solution decreased with increasing concentration, and the higher the intrinsic viscosity of PVAmHCl, the higher the equivalent conductivity of the corresponding PVAmHCl.