Effects of substitution groups on the RAFT polymerization of N-alkylacrylamides in the preparation of thermosensitive block copolymers

Ya Cao, X. X. Zhu, Juntao Luo, Huiyou Liu

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to prepare a series of homo- and copolymers of N-alkyl-substituted acrylamides. The acrylamide monomers have similar chemical structures, but they all exhibit difference in reactivities, especially between N-monosubstituted and N,N-disubstituted acrylamides during the RAFT process. Results from size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometry indicate chain transfers to monomers are easier to occur for N-monosubstituted polyacrylamides, with negative deviations of the molecular weights from the theoretical values. The high transfer activity makes them good macro-chain transfer agents (CTAs). The stronger electron-donating conjugative effect renders the disubstituted acrylamides more reactive, meaning that they can react more readily with monosubstituted polyacrylamide-CTAs to form a sequent block. Tri- and tetrablock copolymers with multiple thermosensitivity have been successfully prepared and tested following these guiding principles.

Original languageEnglish (US)
Pages (from-to)6481-6488
Number of pages8
JournalMacromolecules
Volume40
Issue number18
DOIs
StatePublished - Sep 4 2007
Externally publishedYes

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Acrylamides
Polyacrylates
Block copolymers
Substitution reactions
Copolymers
Monomers
Polymerization
Size exclusion chromatography
Homopolymerization
Ionization
Mass spectrometry
Macros
Desorption
Acrylamide
Molecular weight
Electrons
Lasers
polyacrylamide

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

Effects of substitution groups on the RAFT polymerization of N-alkylacrylamides in the preparation of thermosensitive block copolymers. / Cao, Ya; Zhu, X. X.; Luo, Juntao; Liu, Huiyou.

In: Macromolecules, Vol. 40, No. 18, 04.09.2007, p. 6481-6488.

Research output: Contribution to journalArticle

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AB - Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to prepare a series of homo- and copolymers of N-alkyl-substituted acrylamides. The acrylamide monomers have similar chemical structures, but they all exhibit difference in reactivities, especially between N-monosubstituted and N,N-disubstituted acrylamides during the RAFT process. Results from size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometry indicate chain transfers to monomers are easier to occur for N-monosubstituted polyacrylamides, with negative deviations of the molecular weights from the theoretical values. The high transfer activity makes them good macro-chain transfer agents (CTAs). The stronger electron-donating conjugative effect renders the disubstituted acrylamides more reactive, meaning that they can react more readily with monosubstituted polyacrylamide-CTAs to form a sequent block. Tri- and tetrablock copolymers with multiple thermosensitivity have been successfully prepared and tested following these guiding principles.

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