Solution Properties of Some Cationic Polyelectrolytes

The solution properties of some cationic polyelectrolytes with ammonium quaternary centers either attached to an acrylic macromolecular chain (polycation PDMAEMQ type) or in the backbone (polycation PCA type) have been measured in order to identify how charge density, polyelectrolyte concentration, solvent polarity as well as temperature influence their behavior in solution by viscometric, conductometric and rheological methods. The viscometric data revealed that all copolymers PDMAEMQ exhibit a polyelectrolyte behaviour in water and methanol and were plotted in the terms of Rao equation. Straight lines were obtained in all cases, allowing the calculation of intrinsic viscosity, [η]. Data from the conductometric study emphasized for PDMAEMQ 50 and PCA 5 an increase of the equivalent conductivity values, Λ, with decreasing concentration over the whole concentration range in water, methanol and their mixture (1:1). The comparison between the complex viscosity values η*, at the same polymer concentration, c p = 4%, for PCA 5 D 1 and PCA 5 shows higher values in the whole interval of temperatures under study (T = 10-60 C°) and a pseudoplastic behaviour at temperatures higher than 50°C for the former system.