Amphiphilic Poly(acrylic acid-b-styrene-b-isobutylene-b-styrene-b-acrylic acid) Pentablock Copolymers From a Combination of Quasiliving Carbocationic and Atom Transfer Radical Polymerization

Document Type

Article

Publication Date

3-10-2005

Department

Polymers and High Performance Materials

Abstract

Amphiphilic poly(acrylic acid-b-styrene-b-isobutylene-b-styrene-b-acrylic acid) (PAA-PS-PIB-PS-PAA) block copolymers were prepared using a combination of quasiliving carbocationic and atom transfer radical polymerization (ATRP) techniques. Poly(styrene-b- isobutylene-b-styrene) (PS-PIB-PS) block copolymer macroinitiators with targeted molecular weights and high degrees of chain end functionality (F-n > 1.7) were prepared by quasiliving carbocationic polymerization of isobutylene followed by sequential addition of styrene. Poly(tert-butyl acrylate-b-styrene-b-isobutylene-b-styrene-b-tert-butyl acrylate) (PtBA-PS-PIB-PS-PtBA) pentablock terpolymers with targeted molecular weights and low polydispersities (PDIs) were synthesized from the PS-PIB-PS macroinitiators, via ATRP of tBA using either a Cu(I)Cl/1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA) or Cu(I)Cl/tris[2-(dimethylamino)ethyl]amine (Me6TREN) catalyst system. Deprotection of the tert-butyl groups using trifluoroacetic acid at 25 degrees C resulted in the formation of PAA-PS-PIB-PS-PAA pentablock terpolymers. Comonomer composition of the final terpolymers, determined by H-1-NMR spectroscopy, was very close to theoretical. (c) 2005 Elsevier Ltd. All rights reserved.

Publication Title

Polymer

Volume

46

Issue

7

First Page

2141

Last Page

2152

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