This paper describes the equilibrium reaction of chitosan in the presence of a strong acid HCI; the degree of protonation is determined as a function of the initial concentration of acid in which chitosan is dispersed. The solubilization of chitosan is obtained for a minimum degree of protonation α = 0.5 at a stoichiometric ratio [HCl]/[Chit-NH2] ≈ 0.5–0.6. The degree of protonation is determined by potentiometry and conductimetry The conductivity of an acidic solution decreases in the presence of chitosan: it passe-through a minimum at a degree of protonation equal to approximately 1. Under the same conditions, the relative viscosity passes through a maximum corresponding to a degree of protonation of around 0.75; it then decreases because of an excess of highly dissociated acid. The salting out of chitosan is estimated at an acid concentration of larger than 1 M.

Three novel ionic monomers having highly delocalized anions and electrochemically stable mobile cations, namely, 1-butyl-1-methylpyrrolidinium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethane-sulfonyl)imide, 1-butyl-1-methylpyrrolidinium 1,1-dicyano-1-[(3-(methacryloyloxy)propylsulfonyl)]methanide and 1-butyl-1-methylpyrrolidinium 1-cyano-1-[(3-(methacryloyloxy)propylsulfonyl)]imide were synthesized and characterized. The structure of these monomers was designed to be a mimic of the most highly conductive bis(trifluoromethylsulfonyl)imide, tricyanomethanide and dicyanamide anions. By radical polymerization procedure a series of new anionic “polymeric ionic liquids” (PILs) were prepared. The solubility of these linear PILs, thermal stability, glass transition temperatures, molar masses and ionic conductivities were estimated. An advantage of the novel PILs was demonstrated by the comparison of their ionic conductivity at 25 °C (2.0 × 10⁻⁸ ÷ 1.6 × 10⁻⁷ S cm⁻¹) with the unmodified poly(1-ethyl-1-methylpyrrolidinium 3-(methacryloyloxy)propane-1-sulfonate) analog. The increase in ionic conductivity is as high as three orders of magnitude and was found to depend on the size of the attached anion. The new ionic monomers were subsequently copolymerized with poly(ethylene glycol) dimethacrylate and poly(ethylene glycol) methyl ether methacrylate. The investigation of the copolymers properties revealed further improvement of the conductivity in approximately two orders of magnitude and the achievement of σ = 4.8 ÷ 6.8 × 10⁻⁶ S cm⁻¹) at 40 °C.