Preparation and properties of novel low dielectric constant benzoxazole-based polybenzoxazine

A novel benzoxazine monomer containing a benzoxazole group was synthesized using a nonsolvent method and then named DAROH-a. The structure of DAROH-a was confirmed by FTIR, 1H NMR, elemental analysis, and mass spectrometry. The curing reaction activation energy was calculated at 140 kJ/mol. Its corresponding crosslinked polybenzoxazines, poly(DAROH-a), displayed a higher glass transition temperature at 402 degrees C, a 9% weight loss at the said temperature, and a high char yield of 42 wt % (800 degrees C, in nitrogen). Moreover, the dielectric constants of poly(DAROH-a) were low and changed only slightly at different temperatures. Furthermore, the dielectric constants and dielectric loss of poly(DAROH-a) at the same frequency barely changed from room temperature to 150 degrees C. The photophysical properties of poly(DAROH-a) film were also investigated. Poly(DAROH-a) showed an absorption peak at 280 nm. The photoluminescent emission spectrum of poly(DAROH-a) film displayed predominant emission peaks at 521 nm. It might have potential application as high-performance materials because of its excellent dielectric constants stability and thermal stability under high temperature. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012