Synthesis of poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABA block copolymers by the combination of quasiliving carbocationic and atom transfer radical polymerizations

Ákos Szabó, Györgyi Szarka, Béla Iván

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Systematic investigations are carried out on the synthesis of a series of new, unique ABA-type triblock copolymers consisting of the hydrophobic and chemically inert polyisobutylene (PIB) inner and the hydrophilic comb-shaped poly(poly(ethylene glycol) methacrylate) (PPEGMA) polymacromonomer as an outer block. Telechelic PIB macroinitiators with narrow molecular weight distributions (MWD) are synthesized by quasiliving carbocationic polymerization of isobutylene with a bifunctional initiator followed by quantitative chain end derivatizations. Atom transfer radical polymerization (ATRP) of PEGMAs with various molecular weights is investigated by using these macroinitiators. It is found that CuBr is an inefficient ATRP catalyst, while CuCl leads to high, nearly complete conversions of the PEGMA macromonomers. Gel permeation chromatography (GPC) analyses reveal slow initiation of PEGMA at relatively high PIB/PEGMA ratios or with PEGMAs of higher molecular weights due to steric hindrance between the macroinitiator and macromonomer. The occurrence of slow initiation, and not permanent termination, is proven by highly efficient ATRP of a low-molecular-weight monomer, methyl methacrylate, with the block copolymers as macroinitiators. Successful synthesis of PPEGMA-PIB-PPEGMA ABA block copolymers is obtained by using either low-molecular-weight PEGMA or relatively low macroinitiator/macromonomer ratios. Differential scanning calorimetry (DSC) indicates phase separation and significant suppression of the crystallinity of the pendant poly(ethylene glycol) (PEG) chains in these new block copolymers. (Figure Presented).

Original languageEnglish
Pages (from-to)238-248
Number of pages11
JournalMacromolecular Rapid Communications
Volume36
Issue number2
DOIs
Publication statusPublished - Jan 1 2015

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Keywords

  • Atom transfer radical polymerization
  • Block copolymers
  • Comb-shaped poly(poly(ethylene glycol) methacrylate)
  • Polyisobutylenes
  • Quasiliving carbocationic polymerization

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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