Synthesis, Characterization and Rheological Properties, as a Function of Temperature, of Three Associative Polymers with Different Microstructure Obtained by Solution Polymerization

Summary

In this work a study of the synthesis and characterization of several associative water-soluble polymer families, consisting of acrylamide (AM), N-isopropylacrylamide (NIPAM) and N,N-dihexylacrylamide (DHAM) is presented. Three different polymer structures: telechelic (with hydrophobic groups at the chain ends), multisticker (with hydrophobic groups along the polymer chain) and combined (with hydrophobic groups along the chain as well as at the chain ends) were prepared via free radical solution polymerization, using a hydrophobic initiator derived from 4,4’-azobis(4-cyanopentanoic acid) (ACVA) containing linear chains of 12 carbon atoms (C₁₂). The viscoelastic properties of these different families of associative polymers were investigated using steady-flow experiments in aqueous solution. The structures as a function of surfactant (sodium dodecylsulfate, SDS) concentration and temperature were investigated. It was observed that the viscosity remains fairly constant up to a certain temperature (“breaking point”) and then decreases with increasing temperature. The breaking point occurs at 40 °C in the case of the telechelic polymers, at 50 °C for the multisticker polymers and at 60 °C for the combined polymers.