Synthesis,characterization, and modification of poly(tert-butyl methacrylate-b-alkyl methacrylate-b-tert-butyl methacrylate) by group transfer polymerization

Different poly(tert-butyl methacrylate) (PTBMA)-poly(alkyl methacrylate) (PAMA, alkyl=CH₃, n-C₄H₉) triblock copolymers were synthesized by group transfer polymerization. They were obtained by first preparing “living” PAMA using a difunctional initiator, followed by polymerization of TBMA in THF at room temperature, in the presence of a nucleophilic catalyst. The segment molecular weights and compositions of TBMA segment could be controlled by regulating the feed ratio of two monomers and the ratio of monomer to initiator. As supported by ¹H-NMR, IR analysis, and titration, the PTBMA blocks could be quantitatively hydrolyzed into poly(methacrylic acid) (PMAA) blocks whereas the PAMA blocks were not hydrolyzed. The water-soluble amphiphiles prepared by neutralization of the PMAA block displayed surface-active behavior in water, which was characterized by a critical micelle concentration. The thermogravimetric analysis demonstrated the loss of tert-butyl groups. © 1992 John Wiley & Sons, Inc.