Synthesis of polyacrylamide in aqueous solution: solubility

The synthesis of aqueous polyacrylamide solution was evaluated for its solubility in water. The reactions were performed using the acrylamide monomer, solvent and initiator (K2S2O8), with the system under magnetic stirring and heating (60°C) for 4 hours. The assays have been made in proportions below of the acrylamide solubility limit. However, using only water as solvent the reaction was not promising. This is because as the polymer forming it was occurring the medium gelatinization. To overcome this situation used was a mixture water/ethanol in the following proportions: 90/10, 80/20, 70/30, 60/40, respectively. Nevertheless, only achieved success in water/ethanol 60/40, where the polymer had formed was soluble at the end of the reaction. The polyacrylamide obtained was purified by precipitation in acetone, and subsequent dissolution in water and reprecipitation in methanol, with 98% yield. The characterization of the reaction was done by FTIR, identified in which the disappearance of the bands 986, 960 and 840 cm-1 of the own terminal vinyl group of the acrylamide monomer. Moreover, was observed the presence of the band at 732 cm-1 related angular deformation of chain, -(CH2)n- for n>3. The polyacrylamide obtained is the subject of future studies of modification and in chelation applicability.