Study On Synthesis And Self-assembly Of The Amphiphilic Random Copolymers

In this paper, the amphiphilic random copolymer poly (styrene-co-acrylic acid) (P(St-co-AA)) and the graft copolymer PSt-g-PAA were respectively synthesized by solution polymereization and the macromolecular macromonomer technique.A series of P(St-co-AA) copolymers were synthesized by free radical polymerization in dioxane and were characterized by means of FTIR, 1H-NMR, GPC and DSC. The micelle solutions of P(St-co-AA) were prepared in the selective solvent dioxane/H2O by self-assembly. The micellization action of P(St-co-AA) were studied by means of DLS, TEM, SEM. The results showed P(St-co-AA) can be self-assembled into regular sphere micelles. Content of AA in the random copolymer P(St-co-AA) and conditions of micellization have effections on critical water content(CWC), formations of micelles and radius (Rh) of micelles. In addition, the ability of pyrene absorption of the copolymer micelles was studied. This work, therefore, displays a potential use of the micelles in the purification of contaminated water.The polymerization of Poly(tert-butyl acrylate) with a halogen atom end group (PtBA-Br) was synthesized by bulk ATRP at 90oC. Ethyl-2-bromo-propionate (EPN-Br) was selected as initiators, N,N,N′,N″,N″-Penta-methyldiethylenetriamine (PMDETA) as ligand, with CuCl as catalyst. Further more, the macromonomer of poly(tert-butyl acrylate) with a C=C double end group (AA-PtBA) was successfully prepared by the nucleophilic substitution of halogen atom to acrylic acid. The characterization of the polymers were determined by FTIR, 1H-NMR and GPC.PSt-g-PtBA was synthesized by free radical polymerization in dioxane, where the molar ratio of St/AA-PtBA was different. And then the tert-butyl group was hydrolized by Trifluoroacetic acid (TFA) to prepare the amphiphilic graft copolymer PSt-g-PAA,The graft copolymer was self-assemblized in the selective solvent H₂O/DMF, the TEM results showed its regularized spheres. The water content, AA content in the graft copolymer has effects on the radius of micelles and CWC value. And the critical concentration of the micelles can also be effected by NaCl concentration.