Synthesis of hydrophobically modified polyacrylamide in inverse miniemulsion

Abstract

In this thesis, two important aspects have been considered: the development and characterization of the miniemulsion technique for the synthesis of hydrophobically modified polyacrylamides, and the investigation of their associative and rheological properties. The synthesis of HM polyacrylamides in inverse miniemulsion was initially optimized by free-radical polymerization of acrylamide initiated by AIBN. The possibility of copolymerization of monomers with different hydrophilicities was shown then on the acrylamide-styrene and acrylamide-lauryl methacrylate model pairs. Then the series of high-molecular weight water-soluble HM polyacrylamides with hydrophobic LMA units was obtained with high yield. It was shown that solutions of these polymers possess the increased viscosity in comparison with solutions of corresponding polyacrylamides. In this study, the new surface-active initiating system based on tetravalent cerium salt and emulsion stabilizer for polymerization of vinyl monomers in inverse miniemulsions has been proposed for the first time. It was found that polymerization of acrylamide proceeded under these conditions with the formation of water-soluble monochelic HM polyacrylamides containing the residual of stearic acid as hydrophobic end-group. Also we showed the possibility of copolymerization of acrylamide with hydrophobic monomers - styrene and LMA. The designed surface-active redox system initiates polymerization on the interfacial boundary but does not initiate polymerization in oil phase that provides the absence of hydrophobic homopolymer in the reaction products. Finally, chemically cross-linked nanoparticles based on polyacrylamide and polyacrylic acid were synthesized in inverse miniemulsions with the developed initiating system. The resulting nanoparticles were easily redispersable in hydrophobic, so as in hydrophilic medium.