Polyarylene Networks via Bergman Cyclopolymerization of Bis-ortho-diynyl Arenes

Authors


  • Acknowledgment is made to the donors of The Petroleum Research Fund, administered by the ACS, National Science Foundation CAREER Award (DMR 9985160 and DMR 0514622), Army Research Office, and the National Textiles Center for financial support. We thank Clemson University and The Dow Chemical Company for support of this work, P. Townsend, V. Snelgrove, B. Seliskar, D. McCrery, J. Haung, and J. Godschalx of Dow for valued expertise, H. Beckham of the Georgia Inst. Tech. for solid state NMR data.

Abstract

Bis-ortho-diynylarene (BODA) monomers, prepared from common bisphenols in three high yielding steps, undergo free-radical-mediated thermal polymerization via an initial Bergman cyclo-rearrangement. Polymerization is carried out at 210 °C in solution or neat with large pre-vitrification melt windows (4–5 h) to form branched oligomers containing reactive pendant and terminal aryldiynes. Melt- and solution-processable oligomers with weight-average molecular weight Mw = 3000–24 000 g mol–1 can be coated as a thin film or molded using soft lithography techniques. Subsequent curing to 450 °C affords network polymers with no detectable glass transition temperatures below 400 °C and thermal stability ranging from 0.5–1.5 % h–1 isothermal weight loss measured at 450 °C under nitrogen. Heating to 900–1000 °C gives semiconductive glassy carbon in high yield. BODA monomer synthesis, network characterization and kinetics, processability, thin-film photoluminescence, and thermal properties are described.

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