Synthesis, characterization, and properties of amphiphilic block copolymer of acrylamide-styrene by self-emulsifying microemulsion method

The copolymerization system of acrylamide (AM) and styrene (St) was acquired by using amphiphilic block copolymer PAM-b-PSt with lower molecular weight as polymeric surfactant, and then the microemulsion phase diagram was drawn. The appropriate copolymerization systems were chosen in the phase diagram, and higher molecular weight amphiphilic block copolymers PAM-b-PSt were prepared by self-emulsifying microemulsion method. The chemical composition and structure of the products were analyzed by FTIR, ¹H-NMR, ¹³C-NMR, GPC, and UV; the block structure of products was characterized by DSC, and the hydrophobic association property of the products was studied by the fluorescence probe and rotating viscosity measurement. The results showed that O/W microemulsion was also acquired by using the polymeric surfactant; 3 g polymeric surfactant was only used to disperse 0.25 g St into aqueous solution, which showed higher emulsifying efficiency. At the same time, the use of self-emulsifying microemulsion copolymerizing system can avoid back treatment of small molecular surfactant and the purified block polymer was prepared in one step; the prepared copolymers have good hydrophobic association properties and their aqueous solution showed evident viscosity increment.