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Baek, Jong-Beom
Center for Dimension-Controllable Organic Frameworks
Research Interests
  • Covalent Organic Frameworks (COFs), Carbon Nanotubes(CNTs), graphene, Energy Conversion and Storage

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Self-controlled synthesis of hyperbranched poly(ether ketone)s from A(3)+B-2 approach via different solubilities of monomers in the reaction medium

Cited 26 times inthomson ciCited 28 times inthomson ci
Title
Self-controlled synthesis of hyperbranched poly(ether ketone)s from A(3)+B-2 approach via different solubilities of monomers in the reaction medium
Author
Choi, Ja-YoungTan, Loon-SengBaek, Jong-Beom
Keywords
Hydrophilic trimesic acid; Kinetically controlled; Phosphorus pentoxide
Issue Date
200612
Publisher
AMER CHEMICAL SOC
Citation
MACROMOLECULES, v.39, no.26, pp.9057 - 9063
Abstract
Hyperbranched poly(ether ketone)s (PEK's) were synthesized via A 3 + B2 polymerization approach without forming cross-linked products, because the polymer-forming process based on Friedel-Crafts reaction was kinetically controlled by the solubility difference of monomers in the viscous hydrophilic reaction medium, poly(phosphoric acid) (PPA)/phosphorus pentoxide (P2O5). The hydrophilic trimesic acid as an A3 monomer is soluble in the reaction medium, while hydrophobic diphenyl ether and 1,4-diphenoxybenzene as B2 monomers are marginally soluble. It is hypothesized that the gelation was avoided because of the following two factors: (i) self-regulated feeding of the arylether monomers into the system driven by their poor solubility and phase separation from PPA/P2O5 medium; (ii) reaction-medium- induced isolation of growing macromolecules promoted by the high bulk viscosity. Both polymerization experiments based on equimolar or equifunctional stoichiometry (A3: B2) resulted in completely soluble hyperbranched PEK's in polar aprotic solvents when these polymers contained a little amount of solvent residues and only in strong acids if they were rigorously dried. The structural analysis by using MALDI-TOF mass spectroscopy in the low molar mass region provided further confirmation that there was no trace of networks; various sizes of cyclics were detected instead.
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DOI
http://dx.doi.org/10.1021/ma0614996
ISSN
0024-9297
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