ANIONIC-POLYMERIZATION OF ACRYLIC-MONOMERS .5. SYNTHESIS, CHARACTERIZATION, AND MODIFICATION OF POLYSTYRENE POLY(TERT-BUTYL ACRYLATE) DIBLOCK AND TRIBLOCK COPOLYMERS

Different polystyrene (PS)-poly(tert-butyl acrylate) (PtBuA) block copolymers have been synthesized by first preparing “living” PS using mono- or difunctional initiators, followed by polymerization of tBuA in THF at -78 °C. The chain length of PtBuA blocks can be controlled in a predictable way with a very narrow molecular weight distribution when polystyrene macroanions are modified by LiCl as a ligand. Di- and triblock copolymers are obtained essentially free from homopolystyrene as shown by gel permeation chromatography. The phase morphology of a diblock copolymer of about 50/50 molar composition consists of randomly distributed, short alternating lamellae of PS and PtBuA. The PtBuA blocks can be quantitatively hydrolyzed into polyacid blocks as supported by titration,IH NMR, and IR analysis. Subsequent neutralization of the polyacid block with a variety of bases leads to two-phase copolymers containing an ionomer type of component. © 1990, American Chemical Society. All rights reserved.