Reversible addition fragmentation chain transfer polymerization of sterically hindered monomers: Toward well-defined rod/coil architectures

Zachary Szablan, Andrew Ah Toy, Thomas P. Davis, Xiaojuan Hao, Martina H. Stenzel, Christopher Barner-Kowollik

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65 Citations (Scopus)

Abstract

The sterically hindered monomers dibutyl itaconate (DBI) and dicyclohexyl itaconate (DCHI) were polymerized via reversible addition fragmentation chain transfer (RAFT) free-radical polymerization. S,S′-Bis(α, α′-dimethyl-α″-acetic acid) trithiocarbonate, cumyl dithiobenzoate, and cumyl phenyldithioacetate have been used as RAFT agents to mediate a series of polymerizations at 65°C yielding rod polymers ranging in number average molecular weight from 9000 to 92,000 g mol-1. The progress of the polymerization was followed via online Fourier transform-near infrared spectroscopy. The polydispersity indices of the obtained rod polymers were relatively high at 1.4-1.7. The RAFT polymerizations of the hindered monomers used in the present study displayed both ideal living and hybrid behavior between conventional and living polymerization, depending on the RAFT agent used. DCHI rod polymers generated via the RAFT process were subsequently reinitiated in the presence of styrene to produce a range of BAAB and A-B rod-coil block copolymers of molecular weights up to 164,000 g mol-1. The chain extension yields molecular weight distributions that progressively shift to higher molecular weights and are unimodal. Thermogravimetric analysis of the pDCHI-block-pStyrene copolymers indicates thermal degradation in two separate steps for the pDCHI and pStyrene blocks.

Original languageEnglish
Pages (from-to)2432-2443
Number of pages12
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume42
Issue number10
DOIs
Publication statusPublished - 15 May 2004
Externally publishedYes

Keywords

  • Block copolymers
  • Kinetics (polym.)
  • Online Fourier transform-near infrared (FT-NIR) spectroscopy
  • Reversible addition fragmentation chain transfer (RAFT) polymerization
  • Sterically hindered monomers

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