Polyelectrolyte properties of tetrazole-containing copolymers

Abstract

Potentiometric titration and viscometry have been employed to study the polyelectrolyte properties of NH acid copolymers. The introduction of styrene units into the chain of poly-5-vinyltetrazole disturbs the system of hydrogen bonds characteristics of the polymer at low degrees of ionization. For a large fraction of styrene or 1-vinylpyrrolidone units in the chain of poly-5-vinyltetrazole a significant role in the behaviour of the copolymer is played by hydrophobic interactions. The thermodynamic characteristics of the conformational transition have been determined in the copolymers of 5-isopropenyltetrazolewith styrene and 1-vinylpyrrolidone. In the region of copolymer compositions corresponding to sharp rise in the probability of formation of blocks of styrene units the nature of the forces stabilizing the compact conformation changes—from predominantly hydrogen bonds to hydrophobic interactions. In the copolymers containing 1-vinylpyrrolidone both types of interaction show up, their contribution depending on temperature.