Synthesis of polybenzoxazine precursors using thiols: Simultaneous thiol-ene and ring-opening reactions


BEYAZKILIC Z., Kahveci M. Ü. , AYDOGAN B., Kışkan B. , Yagci Y.

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, vol.50, no.19, pp.4029-4036, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 19
  • Publication Date: 2012
  • Doi Number: 10.1002/pola.26202
  • Title of Journal : JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
  • Page Numbers: pp.4029-4036
  • Keywords: benzoxazine, polybenzoxazine, crosslinking, ring-opening polymerization, thiol-ene, thermosets, phenolic resin, HIGH-PERFORMANCE THERMOSET, MAIN-CHAIN, BENZOXAZINE MONOMERS, CLICK CHEMISTRY, POLYMERIZATION BEHAVIOR, PHENOLIC MATERIALS, COUPLING REACTION, ALLYL GROUPS, POLYMERS, MOIETIES

Abstract

A new class of polybenzoxazine precursors of combined molecular structure of benzoxazine in the open and ring form has been developed. Thermally curable benzoxazine networks were obtained by simultaneous photoinduced thiol-ene and Catalytic Opening of the Lateral Benzoxazine Rings by Thiols (COLBERT). The thiol-ene reactions were initiated by photolysis of a free radical photoinitiator, 2, 2-dimethoxy-2-phenyl acetophenone (DMPA), and the competing COLBERT reaction was triggered by thiol compound, 1,2-ethanedithiol, present in the reaction mixture. The extent of reactions was evaluated by conducting experiments both under UV irradiation and in dark using model benzoxazines. The precursor soft films (pre-P(B-ala-DTE)) were prepared by irradiating solutions of diallyl functional benzoxazine (B-ala), 1,2-ethanedithiol and DMPA. The obtained pre-P(B-ala-DTE) films were then cured through thermally activated ring opening reaction of remaining benzoxazine groups yielding a more rigid and tough film. Thermal and mechanical properties of the films were investigated by DSC, DMA and TGA and compared with a typical polybenzoxazine, P(B-ala). (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012